Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/13/2011
Publication Date: 12/2/2011
Publication URL: http://handle.nal.usda.gov/10113/57384
Citation: Anuta, J.D., Buentello, A., Patnaik, S., Lawrence, A.L., Mustafa, A., Hume, M.E., Gatlin, D.M., Kemp, M.C. 2011. Effect of dietary supplementation of acidic calcium sulfate (Vitoxal) on growth, survival, immune response, and gut microbiota of the pacific white shrimp, Litopenaeus vannamei. Journal of the World Aquaculture Society. 42:834-844. Interpretive Summary: Treating feed with acid (acidifier) has been recognized as beneficial to animal production, including fish farm production, where the acidifier improves fish growth and decreases resistance to pathogens. An experiment was conducted to evaluate growth, digestive bacterial populations, and immune system responses of shrimp fed diets containing a commercial acidifier. Weight gain and survival among shrimp fed the acidifier were slightly improved over those shrimp not fed acidifier. Digestive bacterial populations in shrimp fed the acidifier were different from those not fed the acidifier. Shrimp fed the commercial acidifier responded better to induced stress and displayed enhanced immune systems compared with shrimp not fed the acidifier. These results indicate positive shifts caused by the acidifier on digestive bacteria as well as improved immune systems but with no appreciable changes in growth or survival. This information is of interest to aquaculture producers and researchers. Results offer a potential alternative to conventional antimicrobials to improve fish growth and protection against pathogens.
Technical Abstract: Dietary acidifiers have been recognized as beneficial in animal production including aquacultural production of fish where they confer such benefits as improved feed utilization, growth, and resistance to pathogenic organisms. If improvements in growth and immune responses by acidifier supplementation can be confirmed in shrimp, then mortalities due to diseases could be minimized limiting the emergence of disease-resistant pathogens as a potential result of antibiotic misuse. With this in mind, a 35-day feeding trial was conducted to evaluate growth, enteric microbiota populations, and non-specific immune responses of Litopenaeus vannamei fed diets containing the commercial acidifier Vitoxal (Mionix Corporation, 3700 Island Moorings Parkway #20, Port Aransas, TX, USA) in an indoor temperature-controlled, recirculating culture system without any natural productivity. Experimental diets were formulated to contain 0 (basal), 0.4, 1.2, 1.6, or 2.0% Vitoxal by weight. Shrimp were fed in excess of satiation 15 times a day using automatic feeders. Weight gain and survival among treatments were excellent but not significantly different (P> 0.05). Denaturing gradient gel electrophoresis analysis revealed that the enteric microbial community of shrimp fed the basal diet differed markedly from those fed the acidifier on the basis of 64.9% similarity coefficient. Shrimp fed the commercial acidifier at 0.4 - 2.0% responded significantly (P< 0.05) better to induced stress and displayed enhanced immune responses including hemocyte phagocytic capacity, hemolymph protein concentration, hyaline cell counts, and hemolymph glucose, compared with shrimp fed the basal diet. These results point to an enhanced performance in terms of positive shifts in the composition of enteric microbial communities as well as improved immune performance, with no changes in growth or survival.