Studies On Nutritional Physiology Of Major B Vitamins And Mineral-phosphorus For Large Yellow Croaker, Pseudosciaena Crocea R. And Japanese Seabass, Lateolabrax Japonicus

Feeding trials were conducted to investigate the nutritional physiology of B vitamins and mineral-phosphorus for large yellow croaker, Pseudosciaena crocea R. and Japanese seabass, Lateolabrax japonicus. The dietary requirements of riboflavin, pyridoxine, pantothenic acid and folic acid for juvenile large yellow croaker and Japanese seabass were conducted in indoor culture system, and the dietary requirements of phosphorus for juvenile large yellow croaker and Japanese seabass were conducted in seawater floating net cages (1.0╳ 1.0╳ 1.5 m or 1.5╳ 1.5╳ 2.0 m). Results of the present study are presented as follows:1. Survival of large yellow croaker was significantly lower in fish fed the basal diet (0.80 mg riboflavin/kg dry diet) than those of fish fed diets supplemented with riboflavin, but no significant differences in survival were observed among the riboflavin-supplemented dietary groups. Specific growth rate (SGR) was the lowest in fish fed the basal diet (P<0.05),and increased with increasing riboflavin up to 6.60 mg/kg (Diet 3) (P<0.05), and then leveled off (P>0.05). Feed conversion efficiency (FCE) and protein efficiency ratio (PER) in fish fed the basal diet were significantly lower than those of the other dietary groups (P<0.05), and no significant differences were observed among the other dietary treatments (P>0.05). Fish fed the riboflavin-free diet performed poorly in terms of growth parameters and exhibited signs of riboflavin deficiency such as caudal fin erosion, loss of normal body color, lens opacity and photophobia. No deficiency signs were observed in fish fed the riboflavin-supplemented diets. Hepatic D-amino acid oxidase activity (D-AAO) was low in the riboflavin-deficient fish and increased in a dose-response manner with maximum activity being observed in fish fed the 6.60 mg riboflavin/kg diet. The riboflavin concentrations in the livers...