An experiment was conducted to evaluate the effects of degossypolled cottonseed meal(DCM) on Japanese sea bass(Lateolabrax japonicus,(5.04±0.02) g initial body weight).Five experimental diets DCM 0,DCM 25,DCM 50,DCM 75A,DCM 75 were formulated to contain 0,15.2%,30.5%,46%,and 46% DCM to replace 0,25%,50%,75%,75% fish meal protein respectively,and the DCM 75 A was supplemented with lysine and methionine to be similar to DCM 0 for Japanese sea bass.Three tanks were randomly assigned to each diet,and 16 fish were batch weighed and stocked into each tank.Faecal were collected after 2 weeks of normal feeding for nutrients apparent digestibility coefficients(ADCs) determination,and the growth trial lasted for 8 weeks.The results showed that fish fed diets DCM 50 had significantly higher feed conversion ratio(FCR) and lower protein efficiency ratio(PER) than that of DCM 0 group(P<0.05).Fish fed DCM 75A and DCM 75 diets had significantly lower growth performances than those of fish fed diet DCM 0(P<0.05),but the lysine and methionine supplement improved PER of diet DCM 75A diet.There were no significant differences in ADCs of dry matter,crude protein,crude lipid,energy and body composition.The present results indicate that DCM may be included in the diet up to 30.5% as a substitute for fish meal,and it can replace about 50% of fish meal protein.
