Optimial dietary requirements of protein, lipid and carbohydrate for juvenile gibel carp(Carassius auratus gibelio)
In order to investigate the optimal dietary requirements of protein, lipid and carbohydrate for juvenile gibel carp(Carassius auratus gibelio) with initial average weight of(2.85±0.09) g, three-factor second order general revolting combination design was used, the high and low designed levels of protein, lipid, carbohydrate in the diets were of 33% and 26%, 10.5% and 5.5%, 40% and 30%, correspondingly. The experiment lasted for 60 days. The results showed as follows: when WGR(weight gain rate) and SGR(specific growth rate) were biggest but FCR(feed conversion ratio) was smallest, the corresponding dietary protein, lipid, carbohydrate levels followed by 35.05%, 8.23% and 27.65%, 35.62%, 8.63%and 28.16%, 37.15%, 4.56% and 31.48%, respectively. When the above three factor levels were of 33.22%, 5.81% and 25.58%, respectively, VSI(viserosomatic index) was smallest. No significant difference was observed in CF(condition factor)and HSI(hepatosomatic index)among all the treatments(P0.05). There was a negative correlation between moisture content of whole-body and dietary lipid level(P0.05), but a positive correlation between lipid content of whole-body and dietary lipid, carbohydrate levels(P0.05). When the dietary lipid was above 8%, the lipid content of whole-body was increased obviously. No significant difference was observed in protein and ash content of whole-body(P0.05). In this study, the optimal dietary requirements of protein, lipid and carbohydrate for juvenile gibel carp are of 35.05%-37.15%, 4.56%-8.00% and 27.65%-31.48% respectively by comprehensive analysis.