Effects of different dietary levels of L-ascorbyl-2-polyphosphate on growth and tissue vitamin C concentrations in juvenile olive flounder, Paralichthys olivaceus (Temminck et Schlegel)

摘要

This experiment was conducted to study the effects of different dietary levels of vitamin C, L-ascorbyl-2-polyphosphate (ASPP), on growth and tissue vitamin C concentrations in juvenile olive flounder, Paralichthys olivaceus (Temminck et Schlegel). Fish were fed one of six semi-purified diets containing an equivalent of 0, 25, 50, 75, 150, or 1500 mg ascorbic acid (AA) kg(-1) diet (C-0 , C-25 , C-50 , C-75 , C-150 or C-1500 ) in the form of ASPP for 12 weeks. Weight gain (WG) and protein efficiency ratio (PER) of fish fed the C-0 diet were significantly lower than those of fish fed the other diets (P < 0.05), and WG and PER of fish fed the C-25 , C-50 and C-75 diets were significantly lower than those of fish fed the C-1500 diet (P < 0.05). Fish fed the C-0 diet exhibited vitamin C deficiency symptoms such as anorexia, scoliosis, cataract, exophthalmia and fin hemorrhage at the end of the 12-week test. After 12 weeks of the feeding trial, AA concentrations from gill, kidney, and liver of fish fed the C-0 , C-25 , C-50 and C-75 diets were significantly lower than those of fish fed the C-150 and C-1500 diets (P < 0.05). Based on broken line analyses for WG and PER, the optimum dietary levels of vitamin C were 91 and 93 mg AA kg(-1) diet respectively. These findings suggest that the dietary vitamin C requirement could be 93 mg AA kg(-1) diet to support reasonable growth, and greater than 150 mg AA kg(-1) diet may be required for AA saturation of major tissues for juvenile olive flounder under experimental conditions.