Effects of Feeding Regime on Biometric Parameters and Hepatic Enzyme Activities of young Red Sea Bream, Pagrus major

体重5.1gのマダイ幼魚を5群に分けて、3つの群は日間給餌頻度を2回、4回、6回とし、49日間飽食させた。他の2群には日間給餌回数2回の飽食量相当分を4回、6回に分けて投与した。飽食給餌では給餌頻度の増加と共に摂取量、脂肪組織、筋肉脂質が上昇した反面、飼料効率、比肝重量は低下した。4回飽食の場合、腸管長は最も短く、肝臓脂質合成酵素、アミノ基転移酵素活性は高かった。一方、2回分の飽食量を4回、6回に分けて給餌した場合、脂質蓄積に変化はなかったが給餌回数の減少と共に腸管は伸張し、肝臓の糖新生関連酵素、解糖酵素活性は低下し、脂質合成関連酵素が向上した。飼料効率、脂質蓄積、腸管長、酵素活性からみて1日2回の飽食給餌が最適であることが判明した。

In order to obtain optimum feeding conditions in young red sea bream Pagrus major, fish averaging 5.1 g in body weight were divided into five groups. Three groups were fed to satiation at different frequencies (two, four and six times a day) for 49 days. The other two groups were reared with a fixed daily ration corresponding to two times satiation at different frequencies (four and six times a day). In satiation, increasing feeding frequency elevated the amount of total food intake, intraperitoneal fat body ratio and muscle lipid level. However, feed efficiency and hepatosomatic index were depressed. Fish fed to four satiations daily had the lowest intestinal length. Liver lipogenic and aminotransferase activities were significantly higher in the group fed to four satiations daily. Different feeding frequencies at a fixed ration exhibited only small differences in the parameters concerning lipid accumulation. Reduced feeding frequency significantly extended intestinal length. Frequent feeding tended to enhance the liver enzyme activities associated with gluconeogenesis and glycolysis, and depress lipogenesis. The feed utilization, lipid accumulation, intestinal length and liver enzyme activities showed that two satiations daily would be sufficient in young red sea bream.