a1992 Applied Pouluy Science. Inc CARBONATED DRINKINGWATER FOR IMPROVEMENTOF EGGSHELL QUALITY OF LAYINGHENS DURING SUMMERTIME MONTHS KEN W KOELKEBECK', PAUL C. HARRISON, and CARL M. PARSONS Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801 Phone: (217) 244-0195 FM: (217) 244-2871 GEORGE R. MCCAIN The BOC Group, Inc., 100 Mountain Avenue, Murray Hill, NJ 07974 Primary Audience: Egg Producers, Laying Flock Supervisors, Nutritionists DESCRIPTIONOF PROBLEM Summertime temperatures often cause ventilation, avoiding crowded cage situations, laying hens to produce thin and soft-shelled and the use of evaporative pad cooling (limited eggs. Due to this phenomenon, extreme losses to certain areas of the country). Providing op- in income from marketable eggs can occur. timum ventilation is one of the most common Current practical means of maintaining com- technique used to alleviate the effects of heat fortable in-house air temperatures during stress. Bird [l]described how to provide and summer months include maintaining adequate maintain a good ventilation system for layers 1 To whom correspondence should be addressed 195 CARBONATED WATER FOR LAYERS during the summer. Although modern cage warm summertimemonths. The water carbon- layer facilities are well insulated and have ad- ation equipment [5]was developed by AIRCO equate ventilation systems, heat stress prob- Industrial Gases, an operating division of The lems in layer flocks still occur periodically. BOC Group, Inc. [6], and installed in a cage When in-house air temperatures rise layer facility at the University of Illinois Poul- above maximum bird comfort levels (about try Research Farm. During the study, the water 85"F), hens respond by increasing their rate of carbonation device provided the hens with a panting in order to cool themselves and main- constant source of carbonated drinking water tain stable body temperatures. As panting con- through a trigger-type cup watering system. tinues, the physiological state of the blood A total of 288 Single Comb White Leg- changes due to the loss of carbon dioxide. This horn hens of the H&N strain were housed in a produces a condition known as respiratory cage layer house of commercial design with alkalosis which causes a disruption of essential water and feed provided ad libitum. A 16% minerals needed for birds to maintain normal crude protein standard layer diet containing egg laying functions. The effects of high envi- 3.75% calcium and .45% available phosphorus ronmental temperatures have been described was provided for the hens on an ad libitum byOdom[2]. basis. A 17-h daily photoperiod was main- In addition to the negative effects of high tained throughout the study. Hens of two dif- temperatures on egg production and egg size, ferent ages were used. One half of the hens thinning of the eggshell occurs [2]. Early ef- (144) were 46 wk of age (young hens), and forts [3] to correct this problem by adding were assigned randomly to 12 replicate groups sodium bicarbonate to the diet or by enriching of 12 hens each (four adjacent raised wire the air with carbon dioxide led to inconsistent cages, 12 x 18 in, containing three hens per results with regard to maintaining optimum cage). Six of the groups were arranged on the eggshell quality. A later report [4] docu- top level of a double deck cage system with mented beneficial effects of providing carbon- three groups being located randomly in each ated drinking water to laying hens exposed to row of two back-to-back rows. The remaining high environmental temperatures. The posi- six groups were assigned to the bottom level tive effects of carbonated drinking water on (three groups per row of two back-to-back eggshell quality and egg production have not rows). The other half of the hens (144) were 86 been tested under field conditions. wk of age (old hens), and were allocated to 12 The objectives of the present study were replicate groups of 12 hens each as described to evaluate the operation of a water carbona- for the young hens. These hens had been tion unit in a commercial layer facility and to molted previously at 65 wk of age, Within each examine the effects of carbonated versus tap age group, one half of the hens (6 groups) drinking water on eggshell quality and produc- received a continuous supply of carbonated tion performance of laying hens during sum- water and the other half (6 groups) received mertime conditions. tap water through a trigger-type cup watering system. MATERIALSAND METHODS The experimental period began on July 2 A 12-wk experiment was conducted to test and ended on September 24 (12 weeks). Daily the practicality of using a carbonated drinking records of high and low in-house air tempera- water system for laying hens maintained in a tures were maintained and summarized commercial-type cage layer facility during weekly. The pH of the carbonated and tap TABLE 1. Weekly in-house air temperature ('F) WEEK I RANGE I IAMean temperatures represent the average of the low and high daily readings for each week. I Research Report KOELKEBECK et al. 196 water was measured during Weeks 1 and 12 of WATER pH the experiment. Egg production and deaths The pH of the tap and carbonated water were recorded daily. Livability (days was measured at the beginning and end of the alive/total possible days alive) was calculated experiment with a portable pH meter. Mea- from mortality. Egg weight and egg specific surements were taken at points near the car- gravity was measured each week on all eggs bonator and at the end of the 74 cage rows. The produced on two consecutive days. Specific pH of the tap water averaged 7.67, while pH of gravity was determined using the flotation the carbonated water averaged 4.73. We con- method with NaCl solutions varying in specific sider this to indicate that the carbonation unit gravity from 1.056 to 1.096 in .004 increments. acidified the water effectively. These pH val- Egg mass (grams of egg per hen per day) was ues were similar to those reported previously calculated each week using hen-day egg pro- by Odom et al. [4], in which the tap water had duction and average egg weight. Feed con- a pH of 7.79 and the carbonated water had a sumption and feed efficiency (grams of pH of 5.17. egg:gram of feed) was also measured weekly. In previous laboratory tests conducted by Certain data were transformed [7] prior to The BOC Group, Inc. [9], the loss of carbon statistical analysis [8]. dioxide from a sample of carbonated water was 16, 23, and 24%, after exposure to the RESULTSAND DISCUSSIONatmosphere for 1,2, and 3 hours, respectively. Weekly in-house temperatures are pre- Because water consumption occurred at a sented in Table 1. The highest mean daily tem- fairly rapid rate during the present study, hens perature of 84°F occurred during the first that drank carbonated water probably re- week. The daily high temperature imposed ceived a substantial amount of carbon dioxide heat stress during most weeks (with exception at all times. of Weeks 6, 11, and 12) as evidenced by in- creased panting by hens during late afternoon. TABLE 2. Effect of carbonated versus tap drinking water on livability, hen-day, and hen-housed egg productionA PARAMJTER I TREATMENT I YOUNGHENS I OLDHENS I MEAN I SEMB Livability (%)' Carbonated 98.2 93.4 95.gb Tap 100.0 100.0 100.0" Mean 99.1a 96.? t 1 Carbonated 83.1 76.8 79.9" Tap 82.8 77.7 80.2" Mean 83.0a 77.2b 81.6 71.6 76Xa Tap 82.8 77.7 80.2" Mean 82.2a 74.6b -Lmbilityvalues were transformed using a square mot algorithm prior to analysis of variance. lPbMaineffect age means within a mw and within a parameter having no common superscripts are significantly jifferent, while main effect water treatment means within a column and within a parameter having no common iuoerscriots are simificantlv different (PS.05). JAPR 197 CARBONATED WATER FOR LAYERS TABLE 3. Effect of carbonated versus tap drinking water on feed consumption and feed efficiencf OLDHENS I MEAN I SEMB 102.2 I 103.3a I 103.9 103.6 103.8a Mean 102.9a I I 1.00 Feed efficiency Carbonated .482 .481 .482a (g eaTg feed) Tap .480 A75 .4ma Mean .481a .478a *Means of skreplicate groups of 12 hens each per treatment. BPooled SEM for water treatment and age of hen means; 12 groups of 12 hens per mean. aMain effect age means within a row and within a parameter having common superscripts are not significantly different, while main effect water treatment means within a column and within a parameter having common superscripts are not significantly different (P>.O5). LIVABILITY AND EGG PRODUCTION received tap water throughout the 12-week The individual and main treatment means experiment. However, the livability figures for livability, hen-day, and hen-housed egg represent only 6 old hens and 2 young hens production are shown in Table 2. Livability was which died in the carbonated water treatment. significantly lower (PC.05) for hens that were We believe this represents a chance occur- provided carbonated water versus those that rence, not an effect due to water carbonation. 1.090 -CarbonatebYOung -eTap-Young -O-Carbonated-Old *Tap-Old h % 1.085- 0 \ 0 W >I p 1.080- 6 0 1 1.075 - cn CD k E 1.070 1.0651t 1 I I I I 1 0 2 4 6 8 10 12 14 Weeks FIGURE 1. Effect of water treatment and age of hen on weekly egg specific gravity.