Effects of dietary L-carnitine on growth, fat content and biochemical indexes of blood of tilapia (Oreochromis niloticus × Oreochromis aureus).

This experiment was conducted to investigate the dietary L-carnitine requirement of juvenile tilapia(Oreochromis niloticus×O.aureus) through observing the growth of tilapia,analyzing fat content and blood biochemical indexes.750 juvenile tilapia with body weight of(0.30±0.01) g were randomly allotted to five groups,and were fed diets supplemented with different level L-carnitine(0,50,100,150 and 200 mg/kg) for 65d to investigate the effects of L-carnitine on growth,fat content and blood biochemical indexes.The results showed that when tilapia feed were added with 150 mg/kg L-carnitine,tilapia' WGR and CF were 19.91% and 8.42% higher than that of control group(P0.05) respectively;FRC was reduced 31.39%(P0.05)respectively;the amount of fat in muscle was reduced 14.39%(P0.05);the contents of cholesterol(CHOL) and TG were reduced 9.82%(P0.05) and 65.43%(P0.05) respectively;the activities of ALT and AST in Tilapia's plasma were reduced 65.04%(P0.05)and 53.73%(P0.05)respectively;the activity of AMY was reduced 69.36%(P0.05);the content of BUN in Tilapia's plasma was reduced 11.76%(P0.05);the content of ALB in Tilapia's plasma was higher than that of control group(P0.05).Therefore,under this research condition,it is suggested that the supplement of L-carnitine in diets of juvenile tilapia was the best at 150mg/kg.