Effects of the combination of vitamin C and E on growth, liver vitamin C and E , and levels of serum cortisol in stressed and non-stressed juvenile soft-shelled turtles Pelodiscus sinensis

摘要

We studied the effects of the combination of vitamin C and E on growth, liver vitamin C and E, and level of serum cortisol in stressed and non-stressed juvenile soft-shelled turtles. The turtles were fed combination of vitamin C and E at the dosages of 0 and 0 mg/kg diets (control group), 250 and 50 mg/kg diets (experiment Ⅰ group), 2 500 and 50 mg/kg diets （ experiment Ⅱ group ） , 250 and 250 mg/kg diets （ experiment Ⅲ group ） , 2 500 and 250 mg/kg diets （ experiment Ⅳ group ） diets, respectively for 4 weeks . The growth of juvenile soft-shelled turtle was estimated by s pecific growth rate , the level of liver vitamin C and E was analyzed by the method of high pressure liquid chromatogram (HPLC), and serum cortisol was determined by radioimmunoassay . The specific growth rate in the four groups of experiment Ⅰ – Ⅳ were higher than that of the control, whereas no significant difference was observed among experiment Ⅰ – Ⅳ groups. Levels of liver vitamin C and E in non-stressed turtles increased with increase of dietary vitamin C and E, and experiment Ⅱ – Ⅳ groups were significantly higher than those of the control group and experiment I group. After acid stress, levels of liver vitamin C and E in all groups had a tendency to decrease, but there were no significant changes; levels of liver vitamin C and E in experiment Ⅱ – Ⅳ groups were higher than those of the control group, and experiment IV group was higher than the other four groups after acid stress. The level of serum cortisol showed no significant difference among experiment Ⅰ – Ⅳ groups, and though experiment Ⅰ – Ⅲ groups had a decrease tendency compared with control group, there was no significant change; whereas experiment Ⅳ groups was lower than that of control. After acid stress, serum cortisol in control group was significantly elevated, whereas the other four groups showed no significant change, although there was a tendency to increase. Serum cortisol levels in experiment Ⅰ – Ⅳ groups were lower than those of the control group after stress, whereas there was no significant difference among Ⅰ – Ⅳ groups. These results suggest that t he absence of vitamin C and E depressed growth, and their combination had no interactive effect on the growth and serum cortisol levels, whereas they had an effect on levels of liver vitamin C and E in soft-shelled turtles [ Acta Zoologica Sinica 50 (2): 158 - 164 , 2004].