THE EFFECTS OF FISH MEAL REPLACEMENT ON GROWTH PERFORMANCE OF YELLOW CATFISH (PELTEOBAGRUS FULVIDRACO)

To evaluate effects of stickwater, stickwater hydrolysate and fish protein hydrolysate to replace fish meal on the growth performance of yellow catfish (Pelteobagrus fulvidraco), ten isonitrogenous and isolipidic diets were formulated to feed 30 net cages of yellow catfish (18.68±0.10) g for 60 days. A semipurified diet containing 28% fish meal was formulated as a control (FM diet). Other nine non-fish meal diets were formulated with stickwater (SW15, SW30, SW45), stickwater hydrolysate (SWH15, SWH30, SWH45) or fish protein hydrolysate (FPH15, FPH30, FPH45), supplying approximate15%, 30% or 45% fish meal protein of FM diet. (1) Compared with diet FM, diets SW decreased SGR by 9.89%—20.33% (P<0.05, and increased FCR by 18.79%—44.85% (P<0.05). Diet SWH15 and diet SWH45 decreased SGR by 8.79% and 14.84% respectively and increased FCR by 16.97% and 27.88% compared with those of the diet FM (P<0.05). Diet FPH15 and diet FPH45 decreased SGR by 13.18% and 15.38%, and increased FCR by 30.30% and 29.70% compared with diet FM (P<0.05); (2) No significant difference was noticed among diet SWH30, diet FPH30 and diet FM in SGR and FCR (P>0.05); (3) The SGR of diets SWH additionally increased 4.40%—9.39% compared with diets SW, while the FCR decreased 9.81%—15.31% (P<0.05); (4) Compared with diet FM, the FIFO of diet SW30, SWH30 and FPH30 were 0.67, 0.61 and 0.60, respectively, decreased by 67.67% to 70.15% (P<0.05). These results indicated that 28% fish meal protein quality of 8.5% (with dry weight 90%) stickwater hydrolysate (diet SWH30) and 8.2% (with dry weight 90%) fish protein hydrolysate (diet FPH30) have similar growth performance with 28% fish meal in yellow catfish diet, and that the FIFO of these two diets were reduced by 69.95% and 70.15% compared with that of diet FM. The stickwater hydrolysate had better fish growth performance than stickwater. The growth performance and feed efficiency of yellow catfish were significantly decreased when the additive amount of stickwater and stickwater hydrolysate was not suitable.