Submitted to: Journal of the World Aquaculture Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/10/2007
Publication Date: 2/1/2009
Citation: Lim, C.E., Aksoy, M., Klesius, P.H. 2009. Growth response and resistance to Edwardsiella ictaluri of channel catfish (Ictalurus punctatus)fed diets containing distiller's dried grains with solubles. Journal of the World Aquaculture Society. 40:182-192.
Interpretive Summary: Distiller’s dried grains with solubles (DDGS), a co-product of the ethanol industry, is relatively inexpensive, rich in protein, fat, vitamin B-complexes and the immunostimulant B-glucan, and does not contain antinutritional factors commonly found in plant protein sources. It's use in aquaculture diets, however, is very limited due to lack of information on its nutritional value for various fish species. Thus, this study was conducted to evaluate the influence of the dietary levels of DDGS supplemented with lysine as replacements of a soybean meal and corn meal mixture on growth performance, body composition immune response and resistance of channel catfish to Edwardsiella ictaluri challenge. Results show that with lysine supplementation to a level equal to that of the control diet, at least 40% DDGS can be incorporated in feeds for catfish as a replacement of a soybean meal-corn meal combination without affecting their growth, feed and protein utilization efficiency and survival. Although the diets used in this study contain similar levels of protein, energy and fat, fish fed diets containing DDGS accumulated more body fat than those fed the control diet. However, inclusion of DDGS in diets improved some hematological values and immune responses, but the optimum dietary levels varied with parameters evaluated. Increased resistance of catfish to E. ictaluri infection was also obtained in fish fed diets containing DDGS. Information obtained from this study will allow flexibility in least-cost feed formulation leading to lower feed costs, increased profits for fish producers, as well as increase the market demand for the increased supply of DDGS.
Technical Abstract: A study was conducted to examine the effect of dietary levels of distiller’s dried grains with solubles (DDGS) on growth, body composition, hematology, immune response and resistance of channel catfish, Ictalurus punctatus, to Edwardsiella ictaluri challenge. Five diets containing 0, 10, 20, 30 and 40% DDGS with supplemental lysine (Diets 1-5) as partial replacements of a combination of soybean meal (SBM) and corn meal (CM) on an equal protein basis were fed to juvenile catfish (13.33 ± 0.25 g) for 12 weeks. Growth performance and feed utilization efficiency were similar for fish in all treatments. Body lipid and moisture increased and decreased, respectively in fish feed DDGS-containing diets, relative to the control group. Dietary treatment had no effect on red and white blood cell counts. Hemoglobin and hematocrit were significantly higher in fish fed diets containing DDGS than those fed the control diet. Fish fed 20-40% DDGS-diets had increased serum total immunoglobulin, and those fed the 30% DDGS-diet had significantly increased antibody titers 21 days following E. ictaluri challenge. Others immune variables evaluated were not affected by dietary treatments. Cumulative mortality 21 days post-challenge was lower in the groups of fish fed DDGS-containing diets (diets 2-5).