夏花青鱼饵料中的最适蛋白质含量

OPTIMUM LEVEL OF PROTEIN IN DIET FOR BLACK CARP FINGERLINGS

摘要:

用酪蛋白、结晶氨基酸、鱼肝油、糊精、纤维素粉等加上适量的维生素、矿物混合剂所组成的精制饵料,以青鱼夏花为试验对象,经过八个星期的喂养试验,从生长、增重和饵料利用率等指标来评定,青鱼夏花的最适蛋白质含量应为41%。蛋白质含量太高,反而减慢生长,降低成活率,同时似乎还对鱼类有毒害影响。蛋白质含量较低,虽然能很好地利用蛋白质,但鱼生长缓慢。5%以下的蛋白质含量甚至出现减重现象。 根据本次试验结果,可以认为二龄青鱼和老口青鱼应用饵料中蛋白质的含量为33%和28%是适当的。

Abstract:

Protein requirements for black carp (Mylopharyngodon piceus) fingerlings weredetermined by using purifed diet which consists of casein, crystalline amino acids,fish liver oil, white dextrin, crystalline vitamins, mineral mixture and cellulone flour.Prior to investigating the quantitative amino acid requivements of black carp finger-lings, the composition of indispensable amino acids in diets was adjusted to that of wholeegg protein. Thirteen lots, each of 40 fish were raised in polypropylene aquarium.Feeding experiments were continued for 8 weeks. The tests showed that the fish weredecreased in weight when protein level in diet was lesa than 5%, and they were increas-ed obviouslly when the protein level was 5--41%, and there exists a linear relationshipbetween protein level in diet and the weight gained. Excessive protein levels generallyhave toxic effects on fish and will reduce growth and increase mortality. The results of this experiement indicate that the optimum level of protein in dietfor black carp fingerlings should be 41%,based on the growth of fish and food conver-sion ratio. Therefore, the recommended amount of crude protein in practical diets forone year old fish (second-year fish) is 33% and for two years old fish (third-year fish)is 28%.