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Home , Krill, Whiteleg shrimp

Cost saver

Feeding effector

Growth enhancer

A highly attractive feeding stimulant for diets WHITE PAPER by Lena Burri, Ph.D. issues, but there may be differences in effectiveness, THE IMPORTANCE OF CHEMOATTRACTANTS when different sources such as , , mollusks, IN FISHMEAL-CHALLENGED SHRIMP DIETS shrimp, or are compared.

With a total of 4.5 million MT, which is 81% of , A FEED ATTRACTANT SOURCE the global shrimp production, Pacific white Krill meal is made from Antarctic krill ( shrimp ( vannamei) is the most superba), which is a related to shrimp. widely farmed shrimp in the world [1]. To But unlike shrimp that live on the ocean bottom, krill reach economic success in , aggregate in up to twenty-kilometer-long swarms maximal feed consumption with minimal and move up and down the water column. There feed waste is essential. High feed intake and growth depend on a diet that is nutritionally suitable and stimulates special sensory cells (chemoreceptors). Chemoattractants that bind to these receptors are chemical substances capable of eliciting the initial positive behavioral responses in shrimp feeding [2]. These include search, movement and/or location of the food source containing one or more chemoattractants and thereby ensure adequate feed intake and growth. The chemoreceptors are located in both movement appendices and mouth parts, as effective Green microscopic are visible in the stomach of Antarctic krill (Euphausia superba) touch, taste and smell senses that compensate for ’ poor visual sense. are 85 different krill around the world, with Antarctic krill living in the around the frozen continent. Krill are transparent with Water-soluble, low molecular weight compounds, free some red and green colorations. The red is caused amino acids, nucleotides, nucleosides, quaternary by special pigmentation spots that ammonium compounds, phospholipids, biogenic can change in size and intensity [7]. The ability to amines and monosaccharides have all been identified change pigmentation is important to balance darker as feeding effectors that improve attractability and coloration for UV protection, when at the surface, palatability of diets. Increased attractability of diets versus higher transparency for camouflage. The green reduces the feeding response time and thereby can be seen in their digestive system and results limits nutrient leaching and feed waste. This not only from algae they eat. Krill can eat up to 20% of their helps with nutrient-overloaded pond issues, but also body weight per day, but they also have the ability to lowers the energy a shrimp has to spend to find the shrink when starving and can survive without food feed and cost of feed that can make up to 50% of the for up to 200 days. total farming costs. Intensive shrimp farming has extensively used Adult krill can reach a length of 6 cm and has blue fishmeal for its nutrient composition and high light-emitting spots on the body speculated to play a attractability, but stagnant supplies and increasing role in mating, swarm formation or camouflage from prices have led to the use of alternative above when the sun shines on them. Surprisingly, the sources such as plant and rendered by- krill genome is about 12 times the size of the human products [3]. While these changes have the advantages genome. Antarctic krill is harvested in the wild, and of reducing cost and increasing sustainability of the cooked, dried and ground whole krill gives a [4, 5], they can also severely impact shrimp powder of brownish-orange color rich in , growth. Reasons may include the absence of essential phospholipids, omega-3 fatty acids and astaxanthin. nutrients, lower attractability and palatability and antinutritional factors that can suppress feeding stimulus and reduce nutrient bioavailability [6]. A good feed attractant may help to overcome these COMPARISON OF DIFFERENT MARINE FEED ATTRACTANTS A study performed by Nunes et al., 2019 compared the feed preference and growth response of L. vannamei to different marine chemoattractants [8]. A diet with 3% fishmeal was supplemented with either 3% krill meal, squid meal, shrimp head meal, shrimp meal, squid liver meal, meal (positive control), soy protein concentrate (negative control) or 5% liquid hydrolysate.

The results demonstrated that after 74 days the final body weight was highest for shrimp fed the krill meal-supplemented diet (11.97 ± 0.93 g), followed by the positive control (11.11 ± 0.77 g) and squid meal

(11.01 ± 1.17 g) diets. Diets with shrimp head meal, QRILL AQUA shrimp meal, squid liver meal and the negative control showed a lower shrimp body weight when Feed preference was evaluated by feeding shrimp in compared to the positive control, but there was no excess twice a day for 10 days in two separate feeding statistical difference between them. Shrimp fed the trays allocated in fifty 0.5-m3 tanks. When diets were sardine hydrolysate diet achieved the lowest body confronted with each other by their simultaneous weight (10.06 ±1.02 g). delivery, shrimp preferred krill meal and shrimp head meal (comparisons with squid meal and squid liver HIGHEST GROWTH RESPONSE meal showed the same tendency but didn’t reach WITH KRILL INCLUSION statistical significance).

Interestingly, the study showed that feed attractability Final body weight (g) alone does not assure an improved growth d performance of L. vannamei. When shrimp head meal 11.97 was confronted against krill meal, shrimp revealed a higher preference for the shrimp head meal diet. c c 11.11 11.01 b However, the feeding preference observations were b 10.70 b b a not reflected in the final body weight in the growth 10.52 10.47 10.43 10.06 study. After 74 days of rearing, the final body weights of the shrimp that have received the shrimp head POS NEG meal diet were not enhanced beyond the negative

Krill meal Squid meal control and krill meal diets. A reason could be that

Squid liver meal cadaverine, putrescine and tyramine were present Dried shrimpShrimp meal head meal Sardine hydrolysate in shrimp head meal and shrimp liver meal. The presence of these biogenic amines may have resulted

Nunes et al., JWAS, 2019 in a higher feed intake but compromised the nutrient quality of the feed. At harvest, shrimp survival was high, reaching a mean of 93.3 ± 5.8% and was unaffected by the different The growth enhancement advantage observed with raw materials. The highest gained yield was obtained krill meal is apparently a positive balance between with diets containing krill meal and salmon meal. No a higher feed attractiveness and stimulation, and statistical difference was observed in shrimp yield the supply of fresh key dietary nutrients. Similarly, among the other diets. The lowest feed conversion previous studies conducted in both P. monodon ratio (FCR) was achieved with shrimp fed krill meal and L. vannamei have demonstrated the ability of (1.31 ± 0.05) when compared to shrimp head meal krill meal to stimulate feed ingestion and growth (1.47 ± 0.05), sardine hydrolysate (1.47 ±0.07), and performance [4, 5, 9, 10]. squid liver meal (1.45 ± 0.17) diets. CONCLUSION

Results indicated that krill meal acts as a powerful feeding effector and growth enhancer in fishmeal-challenged diets for . The diet with 3% krill meal was the most effective in increasing shrimp final body weight and yield, and in the reduction of FCR in L. vannamei when compared to other marine feed attractants.

The increased growth rate by dietary krill meal inclusion improves production efficiency by reducing a farm’s operational costs and causes shrimp to eat feeds that otherwise would not be attractive (consumed). Earlier harvests and a greater crop turnover increase annual yields and reduce the risk for disease occurrence.

Since Antarctic krill is protected from overfishing by CCAMLR and Aker BioMarine Antarctic AS has obtained the Marine Stewardship Certification to prove sustainable , QRILLTM Aqua is an attractive shrimp feed ingredient that maximizes feed intake in a sustainable manner.

REFERENCES

1. Cai, J., et al., Top 10 species groups in global aquaculture 2017. Food and Agriculture Organization of the United Nations, Rome, Italy, 2019. 2. Derby, C.D. and P.W. Sorensen, Neural processing, perception, and behavioral responses to natural chemical stimuli by fish and . Journal of chemical ecology, 2008. 34(7): p. 898-914. 3. Tacon, A.G. and M. Metian, Global overview on the use of fish meal and in industrially compounded aquafeeds: Trends and future prospects. Aquaculture, 2008. 285(1-4): p. 146-158. 4. Sá, M.V.C., et al., Dietary concentration of marine oil affects replacement of fish meal by soy protein concentrate in practical diets for the white shrimp, Litopenaeus vannamei. Aquaculture Nutrition, 2013. 19(2): p. 199-210. 5. Sabry - Neto, H., et al., Effects of soy protein ratio, lipid content and minimum level of krill meal in plant - based diets over the growth and digestibility of the white shrimp, Litopenaeus vannamei. Aquaculture Nutrition, 2017. 23(2): p. 293-303. 6. Nunes, A.J.P., et al., Behavioral response to selected feed attractants and stimulants in Pacific white shrimp,Litopenaeus vannamei. Aquaculture, 2006. 260(1-4): p. 244-254. 7. Auerswald, L., et al., Physiological and morphological colour change in Antarctic krill, Euphausia superba: a field study in the Lazarev Sea. Journal of Experimental Biology, 2008. 211(24): p. 3850-3858. 8. Nunes A.J.P., et al., Feed preference and growth response of juvenile Litopenaeus vannamei to supplementation of marine chemoattractants in a fishmeal-challenged diet. Journal of the World Aquaculture Society, 2019: p. 1-16. 9. Smith, D.M., et al., The efficacy of ingredients included in shrimp feeds to stimulate intake. Aquaculture Nutrition, 2005. 11(4): p. 263-72. 10. Williams, K.C., et al., Evidence of a growth factor in some crustacean-based feed ingredients in diets for the giant tiger shrimp monodon. Aquaculture, 2005. 250(1-2): p. 377-90.