Submitted to: Fish Nutrition and Feeding Symposium Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 7, 2002
Publication Date: June 7, 2002
Citation: Yildirim, M., Lim, C.E., Wan, P.J., Klesius, P.H. 2002. Growth performance and immune response of channel catfish(Ictalurus punctatus) fed diets containing graded levels of gossypol acetate. Proceedings of Fish Nutrition and Feeding Symposium Proceedings. p. 162. Technical Abstract: A study was conducted to evaluate the effect of dietary gossypol levels on growth, hematology, immune response and resistance of channel catfish to Edwardsiella ictaluri. A purified basal diet supplemented with 0,300, 600, 900, 1,200 and 1,500mg gossypol from gossypol acetate were fed to juvenile channel catfish in quadruplicate aquaria to satiation twice daily for 12 weeks. Final weight gain was inversely related to the concentration of dietary gossypol. Fish fed diets without and with 1,500mg gossypol/kg had significantly highest and lowest weight gain, respectively. Feed intake and feed efficiency were a reflection of weight gain. Survival was not affected by dietary levels of gossypol. Whole body moisture increased whereas lipid decreased with increasing dietary gossypol levels. Body protein was significantly low for fish fed the highest gossypol diet, but did not differ among fish fed the other diets. Body ash did not differ in fish fed diets containing 0 to 900mg gossypol/kg but was significantly higher in fish fed higher levels of gossypol. Liver gossypol content was linearly related to dietary levels of gossypol. Ratio of gossypol isomers (+ and -) in liver of fish fed different diets was relatively constant. Total cell count and red blood cell count of fish fed the two highest levels of dietary gossypol were significantly lower than those of fish fed the control diet. Hemoglobin significantly decreased in fish fed 900-mg or higher gossypol diets. Hematocrit was significantly affected at each incremental level of dietary gossypol of 600mg/kg or higher. Plasma protein did not differ for fish fed the three lowest dietary levels of 900mg or higher gossypol. Macrophage chemotaxis ratio was similar for the groups fed diets containing Superoxide anion production as measured by NBT test did not differ among treatments. Mortality 14-day post challenge with E. ictaluri significantly decreased at dietary gossypol levels of 900mb or higher. However, antibody titer against E. ictaluri 15-day post challenge was not affected by dietary treatment. This study indicates that juvenile catfish were more sensitive to gossypol toxicity than previously reported.