Submitted to: Aquaculture Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 1, 2006
Publication Date: February 26, 2007
Citation: Lim, C.E., Aksoy M., Klesius, P.H. 2007. Growth performance and resistance to Edwardsiella ictaluri of channel catfish (Ictalurus punctatus) fed diets containing distiller's dried grains with solubles. Aquaculture Conference Proceedings. Aquaculture 2007. February 26 - March 2, 2007 San Antonio , Texas. p. 536. Technical Abstract: Distiller's dried grains with solubles (DDGS), a by-product of the ethanol distillery industry is less expensive than soybeal meal (SBM) on a per unit protein basis, but its use in fish feed is limited due to the lack of information on its nutritional value in fish diets. Approximately 98% of the DDGS in North America is from plants that produced ethanol for fuel, while the remaining 1 to 2% is produced by the alcohol beverage industry. In 2001, the U.S. produced about 3.1 million metric tons (mt) of DDGS. As a result of the recent expansion and increase in ethanol production for fuels due to the shortage and rising cost of petroleum-based fuel, the DDGS production in the U.S. has been estimated to increase to more than 8 mt in 2006 and 10-14 mt in the next few years. A feeding study was conducted to examine the effect of dietary levels of DDGS on growth performance, body composition, hematology, immune response and resistance of channel catfish to Edwardsiella ictaluri challenge. Five isocaloric diets containing DDGS at levels of 0, 10, 20, 30 and 40% DDGS with supplemental lysine as replacements of a combination of soybean meal (SBM) and corn meal on an equal protein basis were fed to juvenile catfish (13.33 plus or minus 0.25 g) in four replicate aquaria twice daily to apparent satiation for 12 weeks. There were no significant differences (P is greater than 0.05) among weight gain, feed intake, feed efficiency ratio and mortality of fish receiving various dietary treatments. Whole body protein and ash contents were comparable for all groups of fish. Body lipid and moisture were significantly higher and lower (P is less than 0.05), respectively, in fish feed diets containing DDGS as compared to those of the control. No significant differences were observed among whole body lipid and moisture of fish fed diets containing DDGS. Dietary treatment had no effect on red and white blood cell counts. Hemoglobin and hematocrit values were similar in fish fed diets containing DDGS, but these values were significantly higher than those fed the control diet. Fish fed diets containing 20-40% DDGS had significantly higher serum total immunoglobulin than those fed diets with lower DDGS levels. Serum protein, lysozyme activity, alternative complement, superoxide anion production and macrophage chemotaxis ratio did not differ among fish in various treatments. The number of days at which the first mortality occurred after E. ictaluri challenge was significantly delayed in fish fed diets with 30 or 40% DDGS. Cumulative mortality 21 days post-challenge was significantly highest in fish fed the control diets. The value of this parameter did not differ among fish fed diets containing DDGS. Antibody titer was also lowest for fish fed the control diet but the differences among treatments were not always significant.