점농어 실용 배합사료 개발을 위한 적정 단백질 요구량 설정

The 10-week feeding trial was conducted to determine the optimum dietary protein level of spotted sea bass (Lateolarbrax maculatus). Two replicate groups of fish initially averaging body weight 7.7g were fed the five commercial extruded pellet diets containing different protein level from 30, 40, 45, 50 and Taiwan product 50% (50T). Weight gain was the highest in the 50T group, and the lowest in the 30% protein level. Feed efficiency tended to increase with increase of dietary protein level, but decreased in 50% group. Protein efficiency ratio was decreased with increase of dietary protein level, but there were no significantly difference among experimental groups. There were no significantly difference among experimental groups in whole body moisture, crude protein, crude lipid and crude ash contents. Hepatosomatic index (HSI) and visceralsomatic index (VSI) of the fish fed 50T was significantly higher than the others groups. But there were no significantly differences among experimental groups in condition factor. For gastric evacuation rate (PER), all feed were emptied from the stomach and intestine in the 50T group on the 24th hours. Posterior intestine feed were not emptied in the 30% group, and little feed remained from stomach and intestine in 45% group on the 24th hours. But much feed were not emptied from stomach and intestine in 40% and 50% group on the 24th hours. Results from this study suggest that a 45% protein level could be recommended for the optimum protein level of juvenile spotted sea bass, Lateolabrax maculatus.