1. Setting the scene

Nowadays, global layer genetics is ccording to the American Country production in 2011 (tonnes) % of world total in the hands of very few companies Egg Board ‘ are all- and genetics focuses on far more Anatural and packed with a China 23,897,000 36.6 than just performance. Issues number of nutrients. One egg has such as disease/salmonella resis- 13 essential vitamins and minerals USA 5,415,600 8.3 tance, egg quality and shell strength in varying amounts, high quality are among the traits featuring in India 3,490,000 5.3 protein and antioxidants, all for 70 modern genetics programmes. calories. Eggs' nutrients can help Japan 2,482,628 3.8 you with weight management, muscle strength, brain function Mexico 2,458,732 3.7 Consumerism and having a healthy pregnancy. Particularly important for aiding Table 1. Top five countries for egg production (FAOSTAT data, 2014). Then along came consumerism healthy brain function and which had its say in the evolution of pregnancy is choline, which is sumer perception (or mispercep- If we had not been able to manage egg production. The key areas that amply present in eggs’. tion!) about egg production. Why diseases such as Newcastle disease, consumerism impacted on were else would a major fast food chain infectious bronchitis, coccidiosis and salmonella freedom, housing – with only use free range eggs and a major the like, today’s modern, progres- the move to alternative systems, and So, it is easy to comprehend that supermarket claim that its bakery sive industry might never have bird welfare, with issues such as man has eaten eggs since history products are only made from free occurred. cages and beak trimming. began and why today they are range eggs? With the increasing need for agri- regarded as a key component of In fact, much of the recent history culture to be more efficient (sustain- man’s diet. Out of this has grown an of egg production in more devel- Genetics able) and not to waste key primary important sector of global livestock oped countries has been influenced resources, such as land and water, production that is not hindered by by consumer perceptions, such as Our understanding of nutrition also one sometimes wonders how far any religious beliefs or taboos. the anti-cage movement, the anti- paralleled the evolution of the table this move into alternative systems Table 1 shows the top five coun- GMO lobby and others. egg sector by providing rations can go? Will a second generation of tries for egg production and it can Events such as the emergence of which more closely fitted the table intensification occur? be seen how production is to some Salmonella enteritidis in the last egg layer’s needs. Table 3 is designed to make you extent dependent upon a country’s quarter of the last century also did Over time genetics has fine-tuned think. The answers to many of the population, but other factors come much to mould the egg industry of egg production and feed efficiency questions you may have will be into play with regards to per capita today. For example, the vast major- with egg numbers steadily increasing covered in future editions of Egg egg consumption (Table 2). ity of UK flocks now comply with and food utilisation steadily improv- Focus in International Poultry the Lion Code which grew out of a ing. Production. n desire to satisfy customers that Country variations salmonella in eggs was an issue of Table 2. Top five countries for per capita egg consumption (FAOSTAT the past. data, 2009). Countries vary in the proportion of If we look at the history of the egg their production coming from large, sector, much of the success of Country Consumption per person per year (kg) intensive farms. At one end of the today’s industry goes back to inten- spectrum we have the situation of sification, which became possible Paraguay5.5 19.5 smaller farms still being the corner with the control of respiratory dis- Japan 19.1 stone of a rural economy, whereas eases, primarily through vaccination, at the other end we have part of and the control of enteric disease, China 18.5 production reverting to smaller primarily through medication and farms, for example with the return the advent of cages which separated Mexico 18.1 of outdoor production. from their faeces and, latterly, Denmark 16.8 An important factor in this is con- vaccination.

Table 3. Comparison of intensification and alternative systems including free range.

Intensive systems Alternative systems including free range

Land utilisation Very good Often very poor

Biosecurity In the hands of farm management Often in the hands of the Gods

Social structure Birds in small stable groups with defined pecking order Birds in large groups with variable pecking orders Variable – often wastage though spillage and consumption Feed management Usually very good by other animals Water hygiene Only drink supplied water where the hygiene can be easily managed Often access to other water supplies so less control

Bird inspection Sometimes not easy – but easy to check individual birds Easier, but harder when one wants to take a closer look

Stress Easier to avoid trigger stresses like poor weather Birds more susceptible to natural adversities

Disease Limited number – most of which can be managed Return of many old diseases such as tuberculosis and worms

Staffing Large number of birds per staff member. Better working conditions Higher staff cost per hen

International Poultry Production — Volume 23 Number 1 39 2. Salmonella

oday there are still con- Salmonella inside or by the sumers who unfortunately are in that part of the egg which is 7,000 Tregard salmonella and eggs least cooked in boiled eggs and –– All salmonella as being synonymous. This goes therefore often survive! 6,000 –– S. enteritidis back to the Salmonella enteritidis For this reason, soft boiled eggs in eggs problem, which started in with nice runny present a real 5,000 –– S. typhimurium the late 1980s and took over a risk of food poisoning in man. decade to control. This was done Ironically, such eggs are popular 4,000 by giving a significant amount of with the very young and very old – protection to hens via vaccination. two groups of people that are more 3,000 Even so, in some parts of the susceptible to salmonella infections. Cases world this serotype is still an Salmonella on the shell surface can 2,000 important egg borne zoonotic easily get into the egg contents pathogen. when the eggs are cracked open. 1,000 Also, if salmonella get into or near the eggshell pores these can provide 0 In those regions where fowl a route of entry into the egg under 85 90 95 00 05 10 typhoid exists S. gallinarum can be certain conditions. found in eggs but it is of little At the farm level we must provide Year zoonotic consequence. Other food that is safe. We can not pass serotypes occur from time to time the responsibility for ensuring eggs Fig. 2. Japanese data. Note the similarity to the British data in Fig. 1. and if they get into a large or mega are safe on to the consumer, espe- operation their importance in a cially since some eggs are eaten raw, nal clean down and sanitation by view to sampling, your programme country or region can be significant. for example, in mayonnaise. taking up residence in the farm’s might not be robust enough to with- When it comes to eggs, salmonella mouse, rat or lizard populations and stand a legal challenge if something can either be found in the egg or on then infecting the next flock to be goes wrong. the shell surface. The former arise Remain salmonella free placed. Thus, attention needs to be Secondly, vaccination should not by one of two means. Firstly, some given to ridding your farm of such be viewed as a tool for eliminating invasive salmonella serotypes, of The approach to follow is to start populations in the terminal cleaning salmonella but rather as one of which S. enteritidis is a good exam- salmonella free and then to protect programme. greatly minimising salmonella to the ple, invade the hen’s body and then that status so our flocks and eggs If we have started with a level that they are of little signifi- invade ova in the . These ova remain salmonella free. salmonella free flock we must cance, for example, they are unable then become egg yolks. At the outset our poultry houses, endeavour to maintain that status. to create an infective dose. For many years this was consid- bedding material, feed, water and This is all about biosecurity which For those of you who are statisti- ered to be the only such route. day old chicks must all be salmonella has recently been covered in our cally minded this is one reason why However, there is now also some free and ideally we should confirm Poultryhealth BYTES. we can have sampling programmes evidence to suggest that the this by microbiological testing. It is with pre-defined confidence limits. salmonella may get on to the surface also sensible to use suppliers, such This can be complicated by the of ova or be incorporated into the as feed mills and hatcheries, that Use of vaccination fact that in some situations, for first albumin to be laid down, which have a proven salmonella freedom example feed, salmonella are not is that laid closest to the yolk. track record. Another way to counter salmonella homogeneously distributed through- These salmonella can then either We may choose to use an acid or infection in our flock is to enhance out the material. remain in those locations or migrate inclusion of a similar product in the or boost its ability to counter infec- Finally, we need to use a labora- into the yolk as the egg ages and the feed as an extra safeguard. tion and this can be achieved via tory that is competent at isolating integrity of the yolk membrane S. enteritidis is quite capable of vaccination. salmonella. We also need to know reduces. avoiding all the rigours of the termi- Two options are dead vaccines, what we mean by negative and posi- which need to be injected into every tive results. All negative says is the hen, and live vaccines ,which can be test that we were using was unable Fig. 1. Human cases of salmonella in England and Wales (1980-2011). applied by one of the mass vaccina- to detect salmonella in the sample tion routes. Vaccines have been tested. It is not saying that the mate- Onset of poultry vaccination used very successfully in many coun- rial tested is free from salmonella. 35,000 tries. For this reason many laboratories An area which many overlook is report what they once reported as 30,000 –– All salmonella that if you are processing eggs on ‘negative’ as ‘not detected’ today. In the farm, have you got a source of other words, tests on similar sam- –– S. enteritidis 25,000 contamination in your processing ples from the same source on –– S. typhimurium area? another day could well generate a 20,000 different result!For this reason it is not prudent to give guarantees on 15,000

Cases Screen and check flocks salmonella status. The sensible approach is to list the 10,000 Whatever your situation one thing tests done and, if it is the case, state which is especially important is to that all these samples yielded ‘not 5,000 screen and check your flocks and detected’ results. Then you let your products. A basic rule of screening customer carry the risk associated 0 for salmonella is ‘the more you look with the interpretation of the results 80 85 90 95 00 05 10 15 the more you are likely to find’. This and you have issued a statement Year has one or two consequences. that you can defend should the need Firstly, if you adopt a minimalistic ever arise. n

International Poultry Production — Volume 23 Number 2 23 3. Feeding for optimal egg production

by Dr Robert Van Wyhe, technical service nutritionist, Hy-Line International.

Bird appetite increases rapidly he art of formulating layer rations is a delicate balance between feeding for high performance and economics. There is constant Tpressure to improve efficiency and lower operational costs while increasing production. Producers must examine many factors to achieve optimal production; focusing on the rearing period, levels throughout life, and feeding to production throughout lay will address many challenges that are seen in the field.

Feeding the pullet early in lay, compared to the rest of lay, in response to high nutrient In order to optimise egg production demand to meet her requirements during lay, producers must maximise for production, growth, and bone pullet performance. Growth should development. follow the bodyweight curves rec- Diet formulation changes may ommended by the breeding com- need to occur weekly to ensure diet is another issue that can harm pro- mately 2.2g of pany. Feed programs and nutrient density accurately matches feed duction. Producers should regard regardless of size. As size increases, density in the diet should be intake. Many nutrients can be under- the breeder-recommended pro- the egg shell becomes thinner and adjusted to meet these targets. supplied early in lay, causing the grams as a guide for the average more susceptible to breaks. If management interventions dur- birds to go into a negative nutrient flock. Overweight birds and overfeeding ing rearing reduce feed intake or balance. The aim should be to feed each amino acids, specifically methionine weight gain (for example vaccination Sub-optimal feeding of calcium flock according to the potential that and cysteine, and dietary oils or beak treatment), producers can early in lay reduces the skeletal mass it is showing. increase the size of the egg pro- select a more dense diet used earlier of the hen and will reduce shell qual- This will allow the flock to main- duced. in rear to help offset this growth ity late in lay. tain a high rate of production while If egg size becomes an anticipated loss. Average flock body weight is Fig. 1 demonstrates calcium maintaining the desired egg weight issue, producers should initiate a important, but uniformity of the intakes below recommended levels and target bodyweight. program to restrict egg size flock is critical as well. In addition to until approximately 24 weeks of age. In Fig. 2 lysine levels from 40-41 increases when eggs are 2-3g below health or management challenges, Hens coming into lay may reach a weeks were dropped, before pro- the desired maximum for the opera- low uniformity can be a result of high performance peak even though duction indicated the need. Hen day tion. Attempts to reduce egg size insufficient energy, protein or feed nutrient intakes are sub-optimal, but and egg mass production had a cor- after eggs have become too large presentation in the rearing diets or persistency will suffer. Sub-optimal responding drop a week later. are not always successful and usually as a result of poor mix, separation feeding of protein or energy can This is an example of the potential reduce production as well. or ingredient quality. cause post-peak dips. pitfalls of feeding to age rather than Undernourished hens will drop production. Carefully monitoring out of production until a point at feed and performance over time will Summary Feeding during lay which appetite overcomes the allow a producer to better antici- dietary deficiency. pate the necessary timing of dietary To optimise production a producer A successful feeding program during These hens will often have other changes in the future. must adopt a consistent approach lay will have several diets available dips or lack persistency in lay. A well Genetic selection is leading to of: that match nutrient density and developed diet matrix that varies more stable egg weight curves as the l Proper nutrition through the pul- intake within each phase of produc- nutrient levels in the rations accord- bird matures through production. In let stage and peak production. tion. ing to production and intake will some situations it may be necessary l Feeding to production rather than Producers should work with their help reduce the possibility of under- to avoid excessive egg size as a age. nutritionist and feed mill to ensure feeding early in lay and reduce the result of over consumption of nutri- l Consistent monitoring of feed quality feed is provided at the chance of post-peak dips. ents. mixes and quality. n appropriate time of production. Diet selection made solely by age An egg shell consists of approxi-

Fig. 1. A comparison of standard versus actual calcium intake in a Fig. 2. Hen day performance and lysine intake of a commercial Hy- commercial Hy-Line W-36 flock from 18-65 weeks of age. Line brown flock from 18-72 weeks of age (Hy-Line Eggcel program).

6 100

5 80

4 –– Hen day production (%) Lysine (%) 60 --- Hen day production (%) standard 3 --- Actual intake –– Lysine 40 2 –– Standard --- Lysine standard Production (%) 2 Calcium intake (g) 20 1 1

0 0 0 15 20 25 30 35 40 45 50 55 60 65 15 20 25 30 35 40 45 50 55 60 65 70 75 Age (weeks) Age (weeks)

International Poultry Production — Volume 23 Number 3 25 4. More saleable eggs

by Novus International

or any layer operation getting more saleable eggs is the key to increas- 74 ing profitability. Challenges such as dirty eggs, broken and weak shells Fcan lead to poor interior quality due to potential contamination from 72 external pathogens. The most effective way to achieve the highest produc- tion possible is by boosting flock performance through optimal nutrition. 70 +9.7% 68 In order to consistently produce together to develop the shell and high quality eggs, nutritionists must internal structures of the egg. 66 Haugh units after provide a balance of key nutrients to Adequate copper supplementation 10 days of storage sustain the health of the bird to serves as the foundation of a quality 64 ensure product quality. eggshell as it is crucial for shell mem- Trace minerals are one aspect of brane formation. It is an important 62 the diet that should be given more micro- for crosslinks of the Control Mintrex consideration. Maintaining adequate microstructure within the eggshell. mineral balance supports shell Zinc is a critical cofactor for cal- Fig. 2. Increased egg freshness. strength and the internal structure of cium metabolism enzymes, which the egg. work to form the shell. Zinc nutri- Additionally, trace mineral nutri- tion also becomes increasingly was significantly increased with the In layers, these effects support tion plays an increasingly important important late in lay as hens’ pro- inclusion of Mintrex in the diet when improved bird health, eggshell role as hens age, ensuring continued duction may start to decline. compared to a diet supplemented strength and egg quality factors production of plentiful, high quality Additionally, manganese is essential with inorganic trace minerals. which are critical to today’s industry eggs and overall health of the hen. to mucopolysaccharide synthesis, Additionally, eggs were sampled at performance parameters. Optimal performance can only be which is a necessary component for 52 weeks of age and assessed for In addition to performance reached by meeting all nutrient eggshell formation. freshness after 10 days of storage. improvements, feeding layers a spe- requirements of the animal, as well Feeding high quality chelated trace The supplementation of chelated cial mineral enriched diet can as minimising all health challenges. minerals offers significant advantages trace minerals significantly increased enhance the mineral content of eggs when it comes to layer performance Haugh units after 10 days of room they produce. and egg quality. Chelated trace min- temperature storage, which shows Zinc, copper and manganese can Metabolic activities erals offer an improved technology the superior stability of eggs from be passed on to the egg in higher that helps animals reach optimal Mintrex fed hens. levels, provided the animal is fed a Zinc, copper and manganese are nutrition even with reduced mineral highly bioavailable source of those vital to realise optimal performance, supplementation. By including lower trace minerals. particularly in layers, as these trace concentrations of chelated trace Improved eggshell Consumers eating these eggs will minerals have specific roles in minerals, this not only alleviates then have the added benefit of con- metabolic activities directly related excretion concerns, but also signifi- A trial comparing a diet supple- suming more healthy minerals in to eggshell formation. cantly improves production effi- mented with Mintrex and a normal their diet. These trace minerals are essential ciency. feeding program showed improved Mintrex chelated trace minerals cofactors of enzymes required for As a highly bioavailable mineral eggshell quality late in lay, as well as consistently deliver more essential the formation and calcifications of source, Mintrex chelated trace min- improved egg weights without com- trace minerals to the bird, while also the collagen matrix of the egg. erals are absorbed and used by the promising shell strength. minimising mineral excretion. That When adequate supplies of these animal to a much greater degree Comparisons with both inorganic translates into healthier layers, more minerals are not provided to the than comparable trace mineral sup- trace minerals and other organic efficient production and ultimately, hen, egg quality can suffer. For plements. Considering the risk of trace mineral sources indicate improved profitability for the pro- example, a lower shell mass can mineral loss, combined with poten- Mintrex improves tissue supply of ducer. n result when a layer is deficient in tial lost production, the superior zinc, copper and manganese, and manganese, and egg production value is clear. has a direct beneficial effect on con- decreases with a zinc deficiency. Research conducted by Sun et al nective tissue and bone develop- References are available These trace minerals work (2012) showed eggshell thickness ment in poultry. from the author on request

Fig. 1. Improved egg shell quality, with less cracked and broken eggs, Fig. 3. Increased laying rate, especially in late lay. After week 66, the in commercial layers from 72-81 weeks of age. laying rate remained higher for Mintrex birds.

91 14 n Control n n Control 12 Mintrex 89 n Mintrex 10 87 -3.2% 8 85

6 -2.0% 83

4 81 % of lay as from week 66 after three weeks (%) Average total egg loss 2 79 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 0 Cracked eggs Broken eggs Age of laying hens (weeks)

International Poultry Production — Volume 23 Number 4 21 5. E. coli peritonitis in layers

A discussion with Dr John Brown, Zoetis Inc.

The veterinarian suggests culturing he layer industry has made big strides to reduce the prevalence of the abdomen, liver or spleen, and to Escherichia coli peritonitis, but producers still need to guard against obtain a more sterile sample from Tlosses from this potentially devastating disease, says John Brown, the field, long bones can be col- DVM, a senior technical services veterinarian with Zoetis Inc. “Without lected for bone marrow culturing. efforts to protect layers against peritonitis, I have seen increased mortality Routine immunisation of flocks for from the disease persist for as long as 10 weeks,” he says. E. coli with a modified-live vaccine is now common in most layer opera- tions, John reports, adding that it has E. coli peritonitis – an inflammation Unfortunately, antibiotics are usu- helped reduce both mortality and of the peritoneum due to the E. coli ally ineffective during an outbreak of the severity of E. coli peritonitis bacterium – can occur as an oppor- E. coli peritonitis. “Antibiotics used while easing the financial impact of tunistic pathogen secondary to to be helpful, but only for a short the disease. respiratory diseases such as Myco- time,” he comments. “Some producers do not vaccinate plasma gallisepticum or infectious “Mortality would drop after a until an outbreak occurs, but I think bronchitis. However, it is now week or so, but when the antibiotics it is more cost effective to vaccinate known that E. coli can be a primary were pulled, mortality would come before the disease strikes,” John cause of peritonitis in layers. right back up. Treatment would adds. “Peritonitis can strike without have to be repeated over and over; For best results, John recommends Prominent and congested blood warning, and in fact, in some cases the problem was never solved and vaccinating flocks in the pullet house vessels, particularly in the ovary, there are typically few clinical signs treatment costs could be tremen- twice. are compatible with an other than high mortality. You’ll find dous. The vaccine is usually sprayed on inflammatory/infectious process. dead birds in cages, or in cage-free “It has become clear that the best at day of age, then again during the Note the yellowish fibrinous and production, birds tend to be found defence is vaccination coupled with grower stage at 12-14 weeks of age. caseous exudate in the dead in their nests,” John says. strict biosecurity,” John continues. The vaccine can be administered in abdomen. Sometimes, late in lay, E. coli peri- water, “but I feel that spraying the tonitis will present initially as a vaccine on the birds gives better slower rise in mortality and is more Mistaken identity protection,” he says. Biosecurity also includes restricting likely related to calcium depletion visitors on layer farms. Anyone and ensuing cloacal prolapse, which The veterinarian cautions that care- entering a poultry house should be enables E. coli to invade the ful diagnosis is important. Although Biosecurity required to wear clean clothes. and abdomen. bacterial peritonitis is commonly Visitors must be required to wear due to E. coli, it can be easily con- John emphasises that biosecurity is coveralls, shoe covers and a hairnet, fused with peritonitis due to fowl just as important as vaccination for and everyone should wash hands Hens in aviary systems face an cholera bacteria. combating E. coli peritonitis because and use a disinfectant footbath upon increased risk of trauma or inju- Another problem that can be con- the more pathogenic forms of the entering and leaving. rious pecking. Breaks in the skin fused with E. coli peritonitis is non- bacterium can be present in the The tyres of vehicles entering and or vent trauma can become bacterial egg-yolk peritonitis, which environment. leaving the farm should be disin- ports of entry for bacteria. occurs when ova are ruptured into E. coli can be tracked from one fected and there should be pest con- the abdomen by rough handling of poultry house to another and spread trol procedures in place. birds, when birds are moved after via dust from fans. The litter and These measures, coupled with they have already started producing water can be contaminated with E. vaccination of layer flocks against E. or when birds are nervous. coli, which birds can aspirate, result- coli, can go a long way toward con- “I always recommend culturing ing in peritonitis. trolling E. coli peritonitis and reduc- birds with peritonitis to get a proper Good ventilation – particularly ing losses from the disease. diagnosis. That is the only way to efforts to reduce ammonia levels – make sure that initiating E. coli vacci- and water sanitation are an impor- nation is likely to be effective,” he tant part of E. coli infection preven- To learn more about flock health says. tion. solutions visit www.zoetis.com

International Poultry Production — Volume 23 Number 5 25 6. House management

by Rafael Lera, ISA, France.

cult to get a uniform air movement, the circulation fans. The system is eat has a negative impact on layer performance, mainly due and in some cases air speed in the not expensive to install, but not as to lower feed intake, which is, in fact, a natural adjustment made cages can be only 75% of the aisle efficient as pad cooling and should Hby the hens in order to maintain their body temperature when air speed. be properly adjusted to avoid leak- environmental conditions (high temperature or humidity) jeopardise their ing, wet spots in the poultry house ability to lose heat. or even damping the birds. Nozzles Evaporative cooling require good water quality or filter- ing to avoid clogging. The three basic methods for heat power and lay out: the goal is to Evaporative cooling is based on the exchange with the external environ- improve air circulation at bird level. cooling effect produced when water l Pad cooling ment are conduction (contact with vapour is added into air entering the Working as a kind of ‘wet filter’, the litter), convection (heat transfer house, since energy used for evapo- they are mainly made of cellulose, to cool air around the bird) and Prevent heat stress ration is taken from the air in the but plastic models are also available, radiation. form of sensible heat. and are placed over the air inlets When the temperature increases, To prevent heat stress, fans should This system, by reducing the ambi- and wetted by dripping water over blood circulation to peripheral areas start working before the in-house ent temperature, allows the bird to them. is increased for higher heat loss temperature goes beyond 26ºC. lose more heat by convection (by The system requires a sufficient through combs and legs, and wings Forced-ventilated houses, usually exchange with the ambient air) and exhausting fan capacity, so the air are opened up. working on negative pressure, are is very efficient in dry areas. entering the house can be pulled Further increases in temperature, much more efficient for controlling However, this also has some dis- through the dampened pad and exceeding 30ºC, will trigger the next the climate in hot conditions. advantages or limiting factors. The cooled as water evaporates off the step in thermoregulation and birds The so-called tunnel system, with cooling effect will depend on relative pad. will accelerate their breathing rate air flowing at one end of the building humidity of the outside air (the Cooling pads require proper main- (panting), allowing a heat loss of and being extracted by the exhaust- higher the humidity the lower the tenance and cleaning to avoid algae approximately 0.6Kcal per g of ing fans installed at the opposite effect) and as water is evaporated, buildup or being clogged by lime evaporated water via the respiratory end, makes it possible to obtain high moisture in the house increases, scale and will need to be periodically route. However, the temperature air speeds, that are uniform and easy reducing the ability of the birds to replaced. perceived by the bird, usually called to regulate. lose latent heat by respiratory ‘apparent temperature’, will also Air velocity will depend on total means. In fact, evaporative cooling depend on relative humidity and air fan capacity and the cross sectional systems should work during the Management factors speed. area of the house. The more sealed drier periods of the day and stop This is the reason why, in warm the poultry house, the better the when relative humidity is too high to There are certainly many other fac- and humid conditions, the air feels efficiency of the system. avoid extreme heat and humidity tors related to house design, orien- hotter than it actually is (heat index) In hot areas, this type of layer discomfort which can lead to mor- tation, insulation etc that play a key and why using any system to house is usually designed to ensure a tality. A variety of different systems role in environmental house condi- increase the speed of air movement ventilation capacity of at least 5m³ can be used: tions which are not going to be around the birds in the layer house per hour/kg of live weight, and reviewed here. will create more comfortable condi- allowing a high air speed, up to l Fogging nozzles However, it is important to tions, since heat loss by convection 2.5m/second and beyond at bird They are usually installed at the air remember that flexible management is increased (wind chill effect). level. In cage systems, it is more diffi- inlet or, in some cases, in front of is also a very helpful tool to reduce the negative impact of heat. For example: Increasing air speed Table 1. Heat index in poultry (adapted from Nilipour, 1996). l Avoid high stocking density. In floor systems perches can be Proper ventilation is essential to Temperature (ºC) used. supply fresh oxygen and remove not l Provide good quality cold water. only harmful gases, like carbon diox- 21.1 23.9 26.7 29.4 32.2 35.0 37.8 40.6 43.3 In hot climates a layer can consume ide and ammonia, but also dust and up to 300ml of water. This will help excess humidity. 0 17.8 20.6 22.8 24.6 28.3 30.6 32.8 35.0 37.2 birds to regulate their body temper- Increasing the air speed in the ature and compensate for the mois- layer house is very effective in fight- 10 18.3 21.1 23.9 26.7 29.4 32.2 35.6 37.8 40.6 ture losses due to panting. Water ing heat, since it improves heat loss tanks and pipes should be well insu- by convection without changing the 20 18.9 22.2 25.0 27.8 30.6 33.6 37.2 40.5 44.4 lated and drinking lines be regularly relative humidity, which means flushed. keeping the capacity of reducing 30 19.4 22.7 25.5 28.8 32.2 35.5 40.0 45.0 50.5 l Use a feed of good texture (75% body temperature through pul- of the particles between 0.5- monary evaporation. 40 20.0 23.3 26.1 30.0 33.8 38.3 43.3 50.0 58.3 3.2mm). Layers have preference for As a rule of thumb, it is considered coarse particles and a drop in feed that an increase in air speed of 50 20.5 23.8 27.2 31.1 35.5 41.6 48.8 57.7 65.5 intake is critical in hot conditions. 0.20m/second reduces the apparent l Adjust the time of feed distribu- temperature by around 1°C. This 60 21.1 24.4 27.7 32.2 37.7 45.5 55.5 65.0 tion in order to maximise feed seems valid for temperatures below intake during the cooler hours of the 30°C; above 35°C the efficacy of air Relative humidity (%) 70 21.1 25.0 29.4 33.8 41.1 51.1 62.2 day. Make sure feeders are empty speed is progressively reduced. once a day, in the middle of the day. In open-sided houses with natural 80 21.6 25.5 31.1 36.1 45.0 58.8 69.4 This will encourage feed intake. ventilation it is not easy to increase l If local regulations allow it, install air flow, but installing circulation fans 90 21.6 26.1 31.1 38.8 50.0 65.5 76.6 a one hour 30 minutes to two hour is a helpful alternative. period of light in the middle of the The efficiency of this system will 100 22.2 26.6 32.7 42.2 56.1 74.4 night (midnight snack) for extra feed depend on the number of fans, fan intake. n

International Poultry Production — Volume 23 Number 6 37 7. Calcium

by Samia Messaoud, Techna France Nutrition, Groupe Techna, France.

ggshell quality is one of the major concerns for egg producers. Downgraded eggs account for 6-12% of all produced eggs. This rate Eincreases drastically after 45-50 weeks old: it can reach up to 20% at the end of laying period. Solidity is therefore a crucial condition for ensuring the profitability of egg producers and the safety of consumers.

The major component of eggshell is the more it maintains adequate calcium (about 95% of the shell is blood concentration all night long calcium): it is deposited at the later (period of shell formation). stage of egg formation. After the All the techniques and conditions deposition of egg membrane in the designed to support calcium avail- uterus, calcium carbonate is precipi- ability at the end of the night for tated on the egg membrane by shell eggshell calcification should there- glands. fore be applied: time of feed distri- About 2.5-3.5g of calcium is bution; distribution of coarse bone-resorbing cells. When the egg fed with a layer feed containing needed for every egg formed; since calcium particles late in the evening; is located in the shell gland, these 3.6% of calcium of which 80% was in demand for calcium is very high dur- midnight feeding; providing calcium cells supply calcium for eggshell for- coarse carbonate form. ing lay, avian species are able to of suitable particle size in the feed. mation by resorption of their rufflers l Group B was fed the same nutri- resort to special and unique ways to borders. tional level as Group A except that mobilise the needed quantity of cal- On the contrary, when the egg is 0.2% of Protical 4+ was added. cium by an increasing intestinal Intestinal absorption located in the upper part of the The supplementation phase began absorption and drawing upon their oviduct (infundibulum, isthmus or as animals reached 61-70 weeks old bone reserves. During lay, calcium intestinal absorp- magnum) the resorption process for the two groups. tion in the duodenum and upper does not occur. In this study, Group B (Protical 4+ jejunum by passive ionic diffusion is at 0.2%) ended up having a better Dietary sources not sufficient to satisfy the high shell quality than Group A (control demand for it. Hence these calcium Other dietary factors feed). Higher shell quantity and Calcium levels in layer diets normally supplies are usually completed by a increase in shell thickness was range from 3.5-3.8%. Calcium can specific active diffusion allowed by a Other dietary minerals and trace observed in Group B as opposed to be provided by several sources such calcium binding protein called cal- elements also play a major role Group A. Shell index was also higher as limestone, oyster shell, calcium cibindin. regarding eggshell quality. Most for Group B than Group A. phosphates, calcium sulphates, meat Once calcium provided in the diet studies have shown the impact of In addition, eggshell solidity (static and bone meal. reaches the blood vessel, it can be phosphorus, vitamin D3, man- stiffness and fracture force) was The source, physical characteristic used directly for eggshell through ganese, copper, zinc, chromium, etc improved by using Protical 4+ sup- and solubility of calcium influence its the shell gland. If this mineral is not on eggshell quality. Other ingredi- plementation in feed. retention time in the gizzard. Even available in sufficient supplies as the ents can also contribute to the same Moreover, Group B achieved though authors often diverge with shell is forming, hens can use their purpose. higher values regarding bone regards to optimal type of calcium own bone reserves. A study focusing on Protical 4+ strength criteria (rigidity, maximum source, particle size and its suitable (Techna France Nutrition) demon- force and fracture force). proportion etc, larger particle cal- strated the positive effect of this As a conclusion, the use of supple- cium sources are commonly known Medullary bones product on eggshell quality. ments like Protical 4+ in layer feed to increase calcium retention in the Experiments were conducted on has proved beneficial on eggshell gizzard. The process of providing calcium two groups each comprised of 240 quality without interfering with bone This time length is closely corre- through bone metabolism to form white commercial layers. Two differ- mineralisation and solidity. Using lated to eggshell quality. Thus the eggs is unique to avian species. ent treatments were applied: Protical 4+ can definitely be efficient longer calcium stays in the gizzard, Osteoclasts of medullary bones are l Group A: this control group was for strengthening the eggshell. n

Fig. 1. Effect of Protical 4+ on egg quality. a,b means followed by different letters are significantly different (P<0.05).

n Group A: Control n Group B: Protical 4+

b 9.44b 0.349 178.7b 8.21b 36.9b

0.342a

a 171.0a 9.25a 8.03

35.0a

Static stiffness Fracture force Shell proportion Shell index Shell thickness (N/mm) (N) (%) 65 weeks 70 weeks

International Poultry Production — Volume 23 Number 7 33 8. Quality criteria

by A. Förster, D. Cavero and R. Schulte-Drüggelte, Lohmann Tierzucht GmbH, D-27454 Cuxhaven, Germany.

Line 1 Line 2 reeding programs for commercial layers pay attention to a large range of egg quality traits in order to optimise the revenue of egg producers Normal Crack Normal Crack Band to satisfy the requirements of table egg consumers. However, (95.7%) (4.3%) (97.9%) (2.1%) layer eggs are not only used for human consumption, but also for hatching chicks. Embryo mortality (< day 18) 6.0% 12.5% 7.5% 32%

Hatch of viable embryos 77.7% 57.0% 85.1% 63.2% Good hatchability and a reduced incubation process will have a great spread of hatch are therefore impact on the hatchability results. Egg weight loss until day 15 8.8% 10.8% 9.8% 12.7% important selection goals in a breed- Furthermore, egg characteristics ing program for improving the num- greatly influence the process of incu- Table 2. Early plus mid embryo mortality (%), egg weight loss during ber and the quality of chicks bation and are responsible for its incubation (%) and hatch of viable embryos (%) of cracked and normal produced by parent stock. success. While some egg quality eggs of two brown egg layer strains. The differences between normal Furthermore, the impact of egg parameter affecting hatchability can and cracked eggs were significant (P<0.001) for the three presented quality traits on hatchability is also hardly be influenced by the manage- traits. measured and taken into account. ment of a breeder flock, others can. There are many factors that affect The aim of this article is to review hatchability, for example the envi- the latter and derive general recom- Table 1 shows the genetic correla- The crack detector allows the ronmental conditions during egg mendations for layer breeder man- tions of egg weight and shell identification of eggs with very small collection and egg handling and agement with special focus on egg strength and with fertility, hatch of hairline cracks, which are not visible specially the configuration of the weight and egg shell quality. set eggs and hatch of viable by the eye. embryos. Although the egg weight loss of A predisposition for high egg the cracked eggs during incubation Table 1. Estimated genetic correlations between reproductive traits weight is related to low hatchability, was not excessively high, the hatcha- and egg quality traits in two white egg layer strains (Adapted from whereas one for high shell strength bility was clearly reduced. Cavero et al. 2011). is related to high hatchability. The test results suggest that egg There is not only a genetic corre- shell quality is crucial for optimum Trait Egg weight Shell strength lation between egg weight and incubation results. The management hatchability, but also a phenotypic and feeding of layer breeders should Line C one. be designed to support shell quality Eggs between 55 and 60g do hatch by an adequate calcium supply and a Fertility -0.08 +0.06 better than heavier eggs, but also healthy liver. In order to achieve Hatch of set eggs -0.43 +0.19 very light eggs show reduced hatch- optimum hatchability the average Hatch of viable embryos -0.46 +0.22 ability. egg weight below 60g should be Table 2 shows the results of a targeted. Line D hatchability test performed with two Special attention should be also Fertility -0.18 +0.10 brown egg laying strains. Before egg paid to all hatching egg handling pro- setting, different egg quality traits cedures to avoid cracked eggs. n Hatch of set eggs -0.48 +0.27 were measured including the Hatch of viable embryos -0.52 +0.29 dynamic stiffness of the egg shell. [email protected]

International Poultry Production — Volume 23 Number 8 43 9. Ventilation systems

by Lasse Kiel Madsen, Segment Manager Layer Industry, and Catherine Brynielsson, Marketing Manager, Munters.

In the design phase, attention also fortable zone for the hens, this is he various egg production systems that are used all over the world needs to be paid to the distance where they will prefer to lay their create a need for flexible and reliable ventilation solutions. The one between the ceiling/attic air inlets eggs and this means that the egg Tthing that should not be flexible or random is the cost of running that so that the optimum air flow inside handling system will take care of the same ventilation system. Farmers and growers want to know that their the building can be reached. product. system performs well, but also what the operation costs are. How do we know that we got it right? Well, there is no second chance; we have to design it cor- Light control Whether a layer farmer uses in temperature, humidity and, for rectly from the start. We know that cages, enriched cages, barn, free example, strong winds. it is working when we see that the The fourth climate challenge for range, aviary or organic production In a large hen house there are sev- birds are very uniformly spread. poultry farms is light control. Getting methods, the climate control system eral design challenges and they are It is not possible to go and clean at least eight hours of sleep is crucial needs to properly ventilate every all more or less unique to every the ventilation equipment during a for layer hens. During summer, nook of the building. If there is a layer house, but it is possible to out- cycle without considerably disturb- especially in the northern hemi- sudden cold spell, the system needs line some general challenges. ing the animals and causing wet lit- sphere, creating eight hours of dark- to be prepared for adding the right ter. Before the flock is replaced, the ness can be pretty challenging in amount of heating power and a sys- entire house including equipment itself. Pitch-black is not necessary tem for emergency opening when Creating uniformity can be hosed down with high-pres- but a brownout effect is. there is a power loss. sure cleaners and disinfectants. Light spots on the floor or cages All of the above, coupled with suf- One important challenge is to create Munters equipment is made for are something the farmer would ficient feed and water access, makes uniformity, especially in an aviary environments that are both dirty want to avoid since it prevents the the laying hens comfortable and free range production system. With and which contain high acidity levels. from falling asleep. Light healthy, which makes them produce the hens being free to move around spots can be avoided by carefully better quality eggs and improves the the layer house, this is essential. designing the climate control system number of hen days. Uniformity means there can be no Bedding quality and choosing products which coun- Munters take great pride in being cold or warm spots in the house. If teract light spots. able to deliver an energy efficient that occurs during cold periods, the The second challenge for a climate Drip pans underneath chimney and well performing climate control hens will be clustered around control system is bedding quality, at fans and deflector disks of ceiling system that fits any of the above warmer spots and there is a risk of least for free range production sys- inlets reflect the light from outside mentioned production systems, and disturbances, overload on the egg tems where birds move around on back up towards the ceiling or walls. also with the objective for the handling system or fighting in the the floor. This typically consists of The reflected light does not prevent farmer/grower to have as low Total flock. The same scenario of cluster- straw, wood shavings or sand. the birds from getting their rest. Cost of Ownership (TOC) as possi- ing will occur during warm periods if The layer farmer wants the bed- ble to increase farm profit. there are cold spots, likewise creat- ding material to remain dry so that it ing an imbalance in the house. does not stick to the birds’ feet and Uniformity always starts with end up in the nests, thereby clinging Choice of parameters placement of the climate equipment to the egg shells and causing dirty for an even distribution of fresh eggs that the farmer will not get paid In most cases the production system incoming air and taking stale air out for. Wet bedding material mixed has been chosen by the farmer of the house. The type of inlet cho- with manure will increase the which more or less decides the lay- sen depends on the climate condi- ammonia levels inside the house, out and design of the ventilation sys- tions where the house is located. negatively affecting both animals and tem. The next thing to take into If the incoming air is cold for a people. A well ventilated building By properly configuring the climate consideration is the ambient climate period of the year, one generally with sufficient air flow and heating system and equipping each project condition of the specific location. wants to avoid that cold air drops on a need basis will ensure that the with the products and accessories Average winter and summer tem- down directly towards the birds, bedding material is kept dry. suitable for that specific location, we peratures and humidity levels as well something which will inevitably dis- So there are advantages for the can make sure that the farmer does as other specific weather types that turb them and cause a non-uniform farmer when it comes to keeping not end up with exhausted animals the climate control system needs to climate. For these cases, a horizontal the bedding material dry; and it all that do not thrive or perform well. be ready for are carefully collected and radial spread of air is desired spells better farm economy and Inlets and extraction openings are and investigated. The control at the which will mix with warmer air next improved profits. handled by actuators managed by a heart of the system will be config- to the attic or ceiling before it drops controller. A back up system makes ured so that it responds to changes down on the flock. sure that animals are not suffocated Floor eggs should there be a power loss at the farm. The inlets and fan dampers will The third challenge for the layer automatically be set wide open farmer concerns floor eggs and how ensuring sufficient natural ventilation to avoid them. It is a cumbersome airflow in case of emergency such as job to collect these (several times power loss. per day) – man-hours that could be Set at the heart of each climate used for other jobs on the farm – control system from Munters, you and it could mean a lost income if will find a number of controllers the floor eggs get dirty. which orchestrate the equipment – There is something that can be the silo controller which controls done to prevent this from happening the feed and the Farm Master and from a ventilation point of view. The Center controllers enabling the ventilation design needs to make farmer to set temperature curves sure that there are no draughts in for the building(s), control the mini- the nesting areas of the layer house. mum ventilation and to track histori- As long as the nesting area is a com- cal data from his/her house. n

International Poultry Production • Volume 24 Number 1 29 10. Careful collection

by the technical team, Vencomatic Group, Holland (vencomaticgroup.com)

aximising the number of first quality eggs that can be sold to the retailer is the key priority for table egg producers worldwide. This Mmeans that eggs must be produced by the hens in the best condi- tion possible, but they must also be collected and packed maintaining the highest egg quality.

An important feature of consump- low egg density may also increase tion eggs, and a significant reason for the risk of egg damage. Next, the rejecting eggs, is the quality of the egg packing machine should handle eggshell. eggs gently, and the number of tran- Even eggs with minor hairline sitions within the egg packer should cracks, a broken shell but with the be minimised. membranes still intact, cannot be sold. Moreover, hairline cracks increase the risk of bacterial con- Evaluating the egg way tamination of other eggs, thereby negatively influencing food safety. Using an electronic egg we are able Within the logistic chain, 2-7% of to evaluate 'The egg way'. This elec- Speedpack – table egg packer. the eggshells are damaged. tronic egg measures the level of Calculating with an average of 4% impact, in terms of acceleration, it damaged eggs, financial losses for a encounters during collisions with before damaging, eggs were individ- the chance of eggshell damage if one farm with 100,000 layers may mount other eggs or materials. We found ually impacted while the impact would be able to strongly decrease up to €16,400 per flock. that the maximum acceleration of an energy varied, and eggshell quality the variation in egg weight and Laying hen breeding companies egg running through the logistic was assessed afterwards. dynamic stiffness. nowadays aim for improving laying chain is typically 15-45G. With this experimental setup it However, from our studies it duration thereby increasing the pro- In order to clearly assess the risks was possible to relate the chance for appears that a decrease of 30% in duction cycles, and the maximum of damage to eggs in the transport eggshell damage to the accelerations impact energy will decrease the risk age of laying hens in the industry. chain we set up several experiments. that were measured from collisions of crack occurrence drastically (by a Since eggshell quality deteriorates In our studies, consumption eggs of inside the transport chain. factor 10), and likewise, an increase with age, this goal may conflict with relatively old (88 week) hens were of 30% will increase the chance of the current quality standards regard- exposed to varying collision severity, crack occurrence by a factor 10. ing eggshell fractures. and fracture occurrence was mea- Reducing damage We found a relatively high sensitiv- This raises the question of which sured. ity of fracture occurrence of con- factors relate to hairline cracks in The collisions in our experiments We found that the chance for sumption eggs of older hens eggs of older laying hens? mimicked the impacts an egg typi- eggshell damage correlates nega- towards realistic collisions in the And, more importantly, how do cally encounters during collection, tively with dynamic stiffness, egg logistic chain. we minimise eggshell damage result- packing, and transportation. weight, shape index, and damping With respect to hairline cracks, a ing from collection, packing, and Of all experimental eggs, the ratio. reduction of collision severity is transportation? mechanical properties were mea- The correlations were not very therefore of first priority when sured, including dynamic stiffness, strong: it seemed that an improve- increasing the age of laying hens. egg weight, shape index, and damp- ment of 50% uniformity in egg The egg way ing ratio. weight and dynamic stiffness would The impact energy on the real egg result in a moderate decrease in the Summary The way an egg travels from the lay- was related to realistic accelerations chance of eggshell damage (by a fac- ing hen to its final destination (the measured inside the transport chain. tor 2). Increasing the age of laying hens in processing industry or perhaps the To find the tolerances of eggs It is probably possible to reduce the consumption egg industry may plate of the consumer) usually con- result in a higher risk for eggshell sists of many transitions, conveyor damage as eggshell quality decreases belts, transportations by truck or The Vencobelt egg carrier. with hen age. otherwise, and they are not always Therefore financial losses may rise, smooth. The journey starts the resulting from rejections of eggs that moment an egg is laid and falls onto are not suitable for consumption as the nest mat. table eggs. The height of the drop and soft- Our investigations show that start- ness of the mat influence the landing ing from a relatively large crack of the egg. Then, a high angle of the occurrence percentage, a substantial nest mat (over 8°) may result in an change in egg mechanical properties extreme speed of the egg when it will cause only a moderate reduc- rolls onto the egg belt behind the tion in the chance of eggshell dam- nest. Also, transitions from one egg age (a factor 2). belt to the other may differ too On the contrary, a moderate much in height. reduction in maximum impact Egg traffic from several belts which energy will drastically reduce the are connected to each other that fracture probability of an egg (a fac- eventually end in the egg collection tor 10). This suggests that in order room, may not be correctly con- to reduce egg fracture occurrence in trolled. eggs, avoiding high impact collisions Overcrowding on the egg belt and is a first priority. n

International Poultry Production • Volume 24 Number 3 35 11. Building a good shell

by Manu De Laet, Nuscience Group, Belgium (nusciencegroup.com)

any egg producers currently produce around 360 eggs per hen 14 housed. Genetic companies are currently breeding for more and Mmore eggs per hen. The production cycles will be extremely pro- 12 –– Control longed and this means that the critical period for second grade eggs and –– Shellbiotic broken eggs will be much longer. 10 8

older may in part be attributed to 6 Building the shell reduced intestinal calcium uptake as well as to increased egg size. 4 econd grade eggs (%)

Building a good shell is like building a The shell of a hen's egg consists of S good house with solid foundations. up to 90-95% calcium carbonate 2 These foundations correspond with which is embedded in a protein 0 the albumen and the surrounding matrix that determines the strength 28 38 48 58 68 78 membranes. of the egg. The better the albumen and mem- Today’s commercial laying hens lay Hen age (weeks) brane quality, the better the calcifi- an egg almost daily and therefore cation process. It is the time require about 4-5g of calcium per Fig. 3. Increase in second grade eggs can be limited by using MCFAs available during the calcification pro- day. The eggshell is made essentially (yellow line = diet + MCFAs). cess which determines the thickness from lime, which is made available of the palisade layer and therefor either from the daily feed supplied the major part of the thickness of or from the bones, especially the urine. If there is an imbalance in the after start of using MCFAs, no effect the shell. However, like while con- medullary bone marrow. intestine due to diseases or bad on hen day production will be structing a house, it would not be The rate at which calcium is nutrition, the rate of calcium absorp- noticeable. solid if no defined structure and no tion will decline, and the calcium However, once the effect has supply to the oviduct will be started, the longer the production decreased. In that case, a lot of sec- period, the bigger the benefit will be ond grade eggs can be expected. (Fig. 2). In the short term the albumen MCFAs for laying hens

Throughout the years, Nuscience has acquired extensive experience with Medium Chain Fatty Acids (MCFAs). With the knowledge of the different effects of MCFAs and Fig. 1. Fluxes of calcium (Nipane et al., 2011). their combinations with Short Chain Fatty Acids (SCFAs) on metabolism cement were used. The same is true removed from the blood during and intestinal health, Nuscience was quality and eggshell quality for the eggshell. The organic matrix eggshell formation is greater than able to increase layer performance. improved, resulting in less second links all the crystals to each other the mean rate of calcium absorption MCFAs have two types of effects. grade eggs (Fig. 3). making it a solid structure. from the feed, and the balance is The long term effect is maintaining Albumen quality is mainly defined corrected by mobilisation of skeletal better laying persistency. and expressed in Haugh Units. This reserves (Fig. 1). Due to the time necessary for folli- Summary parameter is based on the height of The phosphorus liberated simulta- cles to develop from small into the thick albumen surrounding the neously is largely excreted in the mature ones, the first 4-6 weeks With the genetic evolution from the yolk in relation to the egg weight. last decades, production cycles of The higher this value, the better the laying hens have been and are still quality. Fig. 2. Laying percentage MCFA group relative to the laying percent- prolonging. This implies that the risk This albumen quality is a good indi- age of the control group (100 = production is equal in both groups). of ending up with an increasing num- cator for the freshness of an egg and ber of second grade eggs will be for the health of a flock. Albumen bigger. quality commonly declines with the 115 These second grade eggs have a age of the bird. High quality albumen severe negative impact on the results in a direct improvement of 110 profitability of the layer industry and the calcification process. This results should always be minimised. in less broken eggs. Therefore, Medium Chain Fatty 105 Acids (MCFAs) are strongly advised to be used. It is best to start when Egg shell quality 100 maximum egg mass production is decreases with age achieved. This is 4-6 weeks before 95 problems with egg quality might be Many factors have been found to expected. n

Relative hen day production (%) affect eggshell quality, such as dis- 90 ease, nutritional status of the flock, 25 30 35 40 45 50 55 60 heat stress and age. References are available The decline in eggshell quality Age (weeks) from the author on request when the laying hens are getting

International Poultry Production • Volume 24 Number 5 19 12. Feeding for health

by Fernando Cisneros, Global Carotenoid Manager, DSM Animal Nutrition and Health

(VLDL), Low Density Lipoprotein status. aying hens are sometimes affected by health issues due to parasites (LDL) and High Density Lipoprotein Consumers in many countries see (coccidiosis), worms or viruses, thus hampering the absorption and (HDL) are the major lipoprotein eggs with golden yolks as more L deposition of carotenoids and leading to pale egg yolks. A bright yolk classes of avian plasma. appetising and nutritious, and there colour can therefore be considered as an indicator of the good health and It is important to understand the is an opportunity for farmers to performance of the flock. interactions between lipoproteins offer vividly coloured eggs in the and carotenoids to further under- marketplace. stand the physiological status of Similar to the effect of gut infec- Historically, carotenoids have been The feed matrix is thought to be birds. tions, any stress or disease-related known for their egg yolk pigmenting an important determinant for the disturbances in the liver or properties and have been thought to absorption of carotenoids, as bile would decrease carotenoid concen- play specific roles in avian embryonic secretion depends on the amount Yolk colour reflects the tration in the egg yolk. The only way development and hatchability. and type of feed, while bile salts and layer’s health to deliver a brightly coloured egg Nowadays, a growing body of fat determine micelle formation. yolk is to ensure maximum research shows that when specific The pH in the intestinal lumen may Carotenoid absorption and assimila- carotenoid absorption in healthy carotenoids, such as canthaxanthin, also have an effect on absorption, tion involve many factors. In particu- birds that receive enough feed are added to the diet, they can impacting the surface charges of lar, any stress or disease-related carotenoids. improve the antioxidant properties both the micellar particles and the disturbances at gut level would This is achieved through the of the eggs. luminal cell membrane, with less dif- decrease carotenoid deposition into reduced use of carotenoids for fusion resistance at lower pH. the egg yolk and therefore decrease antioxidant functions in order to get It thus appears that carotenoids its colour intensity. maximum deposition into the yolk. Carotenoid absorption are absorbed by passive diffusion In poultry, most carotenoids deliv- Eggs with a golden yolk are the across the brush border membranes ered to the egg yolk are feed- result of a high degree of husbandry Carotenoid absorption from the of the intestinal mucosal epithelium derived. Egg formation is a complex and flock health. intestinal tract can be compared to with a concentration dependent process, involving a substantial the intraluminal, membrane and process. increase in lipid and protein intracellular events of dietary lipids. The efficiency of the dispersion of metabolism in the liver and other Recommendations Although our understanding of carotenoids is also known to be organs. Improvement in genetic potential, as carotenoid absorption in avian affected by the presence or absence Furthermore, carotenoids are well as the increase in the length of species needs further research, of other components in the diet, as important to the health maintenance their cycle of production, may findings suggest that in poultry most well as by the general nutritional of laying hens, and play a key role in impact the rearing of laying hens. of the carotenoids are absorbed in status of the animal. The presence their immunocompetence. Therefore, new nutritional and the jejunum. of fatty acids of varying chain lengths There seems to be a trade-off health solutions must be found to After the ingestion of feed, and the degree of saturation, for between carotenoids transferred to address new challenges. carotenoids are released from the example, substantially affect the egg and those used up by the As the carotenoid content in the matrix by digestive enzymes, includ- carotenoids’ absorption rate. hen. egg can be correlated with the ing lipase, and further emulsified by It is generally accepted that plasma The start of the laying period is health and performance of a flock, bile salts and phospholipids. lipoproteins serve as a transport sys- critical because hens must increase carotenoids, such as the nature- During the hydrolysis of trigly- tem not only for lipids but also for their feed intake quickly to cover the identical canthaxanthin from DSM’s cerides, the monoglycerides formed carotenoids. production of the first eggs. Carophyll red, can be added to feed in the presence of bile salts sponta- In birds, portomicrons, lipopro- This process undergoes hormonal to ensure a golden yolk, every time neously create very small particles teins produced by enterocytes, changes and any deficit can impair (in healthy flocks). n called mixed micelles. serve to transport lipids from the further egg production during the

The solubilising of water-insoluble gastrointestinal tract to the liver via cycle. Therefore, the carotenoid materials, including carotenoids, is a portal circulation. content and the yolk intensity can be References are available critical step in their digestion and Very Low Density Lipoprotein used as good markers for the flock’s from the author on request absorption. Particularly small, mixed micelles are dispersed in the aqueous envi- ronment of the intestinal lumen and can diffuse into the glycol-protein layer surrounding the microvilli or brush border of mucosal cells, where they come into contact with the cell membranes. In general, the unstirred water layer can limit lipid absorption and it seems reasonable to assume that the same is true for carotenoids. It is becoming increasingly evident that micelles formed from dietary lipids serve as a delivery system for carotenoids to reach the absorptive surface of the gut. The micelles facilitate fat absorp- tion by providing a high concentra- tion of lipids in the unstirred water layer adjacent to the mucosal cells and disruption of the micelles is nec- essary for absorption to take place.

International Poultry Production • Volume 24 Number 6 19 13. Improving shell quality

by Jesus Arango, PhD, Statistical Geneticist for Hy-Line International

he practice of extended single-cycle production systems, even those 3500 extended up to 100 weeks without a moult, is attainable today 3000 because of improved persistency of egg production and better envi- 2500 T 2000 ronmental conditions. Additionally, innovative selection programs have 1500

helped make this possible without affecting the performance of flocks man- Amplitude aged in moulting programs. 1000 500 One of the most important conse- The idea is to combine diverse 0 0 200 400 600 800 1000 1200 1400 1600 1800 1 2 3 4 5 6 7 8 9 quences of this production system is measurements at different hen ages Time (Ms) Frequency (x1000 Hz) the need for hens that maintain high to approach shell quality in a holistic quality of eggs for a longer time as manner. The components of the Fig. 2. Acoustic Egg Test (AET), showing the typical frequency spectra they age. The persistency of shell SQC include multiple (at up to four of an intact egg. Frequency spectra graph images from: quality during long periods of egg ages) and repeated records (2-3 http://www.columbus-tester.com/about-columbus production is paramount. Shell qual- eggs) of different measurements ity has been described as the ‘limit- (Fig. 1), which have included: ing factor’ in the evolution of shell quality. In an intact egg, fre- l Direction of measurement of BS single-cycle production because shell l Puncture Score (PS): a non- quency spectra profiles at different is important, and should be consid- quality deteriorates as the hen ages. destructive, semi-static method that quadrants are very similar, and tend ered for selection as genetic correla- Saleable eggs require shells of tests shell’s deformation and plastic- to be dominated by a single peak tions between BSe and BSp are good quality. The eggshell not only ity. It measures displacement of the (Fig. 2). On the contrary, eggs carry- much less than 1.0. provides a natural package for the shell upon applying pressure that ing MCr are characterised by multi- l Genetic correlations between BS egg content, but also provides simulates point of impact, without ple peak profiles, broader frequency and Kdyn are positive but moderate, essential protection from microbial cracking the shell. It had been the and heterogeneous pattern spectra indicating that they measure differ- penetration. single most important shell resis- (Fig. 3). A multiple correlation ent aspects of shell quality. Several factors contribute to tance trait in the breeding program threshold allows defining an intact l Crack detection has poor eggshell deterioration as hens age. for over 45 years, which was vs. a cracked egg. A sound layer response to selection; but its genetic The most important are related to recently discontinued due to the breeding program, among many correlation with BS and Kdyn are calcium nutrition and metabolism: erosion of available genetic variabil- other measurements of efficient egg favourably negative, and of sizable deterioration of the gut’s absorption ity. production, must include different magnitude, particularly with KDyn. Therefore, the incidence of micro- cracks can be efficiently reduced indirectly by increasing BS and KDyn. The ability to detect cracks is important, as egg breakage is one of the most important causes of down- grading eggs during classification. Downgraded eggs are one of the main sources of economic ineffi- Fig. 1. Components of the new shell quality evaluation, from left to right: breaking strength at the equator ciency of egg production. An (BSe) and between the poles (BSp), and the Acoustic Egg Test (AET). approach for a holistic improvement of shell quality (SQC) must aim for ensuring a good shell structure and capacity, inefficient mobilisation of l Breaking Strength (BS): a static measurements of shell quality taken reduced risk for breakage in both body reserves (from medullary and destructive method to test the at different ages or stages of the moulting programs and extended bones) and of deposition of ionic blunt force required to break the production cycle, such as the ones in cycles of egg production. n form to organic form of this mineral egg, which is highly correlated with the SQC described previously. to build the shell wall. shell thickness. Two directions of Results from analyses of these Ref: Arango et al. (2016). Poultry In addition, egg size tends to this measurement have been tested traits indicate that: Science doi: 10.3382/ps/pew286 increase with age enlarging the area and implemented: equatorial (BSe) to be covered by a limited supply of and polar (BSp). calcium carbonate. This calls for a Fig. 3. Acoustic Egg Test (AET), showing the typical frequency spectra holistic approach to improve shell l Acoustic Egg Test (AET): the of a cracked egg. quality in modern layers. most recently introduced method in Shell quality is a complex trait the Hy-Line breeding program. It is a dependent on shell resistance to dynamic method (as it covers the 250 breakage, plasticity and permeability entire eggshell area). It utilises the over its entire area. Hy-Line egg as a resonance chamber and 200 International have been exploring integrates the resonance profile different candidate measurements to measured in four quadrants (at 90 150 be targeted for the improvement of degree rotation) and mass of the egg shell resistance. with its shell resistance, providing 100 Amplitude This has required developing two main outputs: Dynamic Stiffness extensive research (both internal (KDyn) and Micro-crack (MCr) 50 and publicly available in scientific lit- detection. The KDyn is a quantita- 0 erature), which has been sum- tive indicator of integral shell resis- 1000 2000 3000 4000 5000 6000 7000 8000 9000 marised in developing a Shell Quality tance and a good predictor of Frequency (Hz) Bio-complex (SQC) for the occurrence of cracks; therefore a improvement of shell quality. good candidate for improvement of

International Poultry Production • Volume 24 Number 7 49 14. Egg yolk pigmentation

by Fernando Cisneros, Global Category Manager, Carotenoids at DSM.

golden yolk can only come from a healthy hen and in order for a yolk to present an attractive golden colour, the carotenoids have to: A • Be ingested in sufficient quantities. • Be absorbed (via a healthy gut). • Not be used as antioxidants (low immunological challenges). • Not be used as vitamin precursor (good vitamin status).

Therefore the hen, the environ- To the human eye, such com- ment and the feed have to work pounds are yellow to red in colour. together to deliver an attractively Lutein, zeaxanthin and apo-ester pigmented yolk. are yellow carotenoids (wavelength In nature, the male birds with the from 445-450nm), whereas canthax- best colouration will attract the anthin is a red carotenoid (wave- females. This makes sense, because length from 465-470nm). only the healthier individuals will be able to obtain appealing feathers. The same goes for the females: the Egg yolk pigmentation healthier hens will have more carotenoids for their eggs. There are two components of egg Fig. 2. Wavelengths of various carotenoids used for yolk pigmentation. So, in order to have a golden yolk, yolk pigmentation. you need a good quality feed, the The first (referred to as the satura- correct husbandry practices and – tion phase) involves the deposition colour (the second component, or Our scientists in France and more importantly – a healthy hen. of yellow carotenoids to create a colour phase). Switzerland set about constructing yellow base corresponding to a The dose-related colour response the requisite blade and developing DSM YolkFan score around 7. to red carotenoids is higher than the the accompanying recommenda- Pigmentation efficiency Such a yellow base is very impor- response to yellow carotenoids, and tions, with the support of our mar- tant for good saturation of the final the combination of yellow and red keting team in Asia-Pacific. The egg yolk pigmenting efficiency of colour. carotenoids is therefore more cost- Trials were carried out, yolks were carotenoids is determined by two Once the yellow base is estab- effective for egg yolk pigmentation. evaluated via chemical and optical main factors – egg yolk deposition lished, the addition of the red Regarding the relative pigmenting analysis, and the appropriate sam- rate and carotenoid colour (wave- carotenoid canthaxanthin (Carophyll efficiencies of the yellow ples were sent to the ink developing length). red) changes the hue to carotenoids, apo-ester (Carophyll supplier. a more orange-red yellow) is more efficient than Taking yolk colour assessment a l Deposition in egg yolk lutein and zeaxanthin, step forward, DSM is now launching Deposition of dietary carotenoids in the main carotenoids the Digital YolkFan in order to take the egg yolk depends on the individ- in feedstuffs. yolk colour evaluation into the digi- ual carotenoid molecule (Fig. 1). As The very high tal era. A digital extension of the the content of carotenoids in the deposition DSM YolkFan, the Digital YolkFan feed increases, their concentration rate of apo- provides fast, accurate colour evalu- in the egg yolk rises in direct pro- ester ation and can be used in conjunction portion. (Carophyll with the 2016 egg yolk pigmentation yellow) guidelines for optimal, consistent l The colour of carotenoids makes it yolk colour production. The wavelengths of the colours of the most the carotenoids used for egg yolk suitable pigmentation fall between 400nm yellow Consistent colour and 600nm within the visible range carotenoid for of the colour spectrum (Fig. 2). The 16 blade DSM YolkFan. the saturation phase. Carophyll yellow 10% and Carophyll red 10% are free-flowing, granulated carotenoid products. Fig. 1. Egg yolk deposition rates of various carotenoids. They consist of small beadlets in YolkFan development which the carotenoid is finely dis- n Carophyll Yellow tributed in a starch-encapsulated During the last few years, the global plant and carbohydrate matrix to 50 n Carophyll Red egg industry (especially in Asia) has which antioxidants have been 40 been experiencing an accelerated added, making Carophyll products development, leading to a prolifera- animal-free. 30 tion of brands and market offers. The special manufacturing process, The idea of a golden yolk always known as ‘spray-dried coating’, pro- 20 coming from a healthy hen is being tects the carotenoids against oxida- adopted widely and, as a conse- tion and gives them high stability, quence, we have consumers asking water dispersability, outstanding Deposition rate (%) 10 for a deeper shade of colour in their mixing properties, and very good 0 eggs. absorption characteristics. n Apo-ester Lutein and Canthax- Capsanthin For this very reason, DSM cus- Zeaxanthin anthin tomers asked us a few years back Please see page 39 for more for the new and higher blade num- information on the digital bers for the DSM YolkFan. YolkFan available from DSM.

International Poultry Production • Volume 24 Number 8 29