The effects of dietary vitamin C on growth, liver vitamin C and serum cortisol in stressed and unstressed juvenile soft-shelled turtles (Pelodiscus sinensis)
Abstract
We studied the effect of dietary vitamin C on growth, liver vitamin C and serum cortisol levels in stressed and unstressed juvenile soft-shelled turtles. Turtles were fed with vitamin C supplementation at dosages of 0, 250, 500, 2500, 5000 or 10 000 mg/kg diet for 4 weeks. Vitamin C supplementation exerted significant effects on specific growth rate and liver vitamin C concentrations. The specific growth rate peaked in the group fed at 500 mg/kg diet, while liver vitamin C levels increased with increasing dietary vitamin C levels. Serum cortisol concentrations did not differ between groups of turtles fed diets supplemented with vitamin C in the range of 0–10 000 mg/kg. After acid stress, hepatic vitamin C levels were unaffected, while serum cortisol in the control group was significantly elevated (P