Effect of dietary Vc and hibernation on biosynthesis of Vc and liver Vc concentration in juvenile soft-shelled

摘要

This work investigated the effect of dietary vitamin C (Vc) supplementation on the turtle’s biosynthesis of Vc and liver Vc concentration during hibernation. Juvenile soft-shelled turtles ( Pelodiscus sinensis ) with an initial body weight of 29.41 g±5.44 g were randomly divided into three groups: Vc0，Vc500 and Vc2500 groups, six parallels for each group, and ten turtles in each parallel. They were fed with Vc supplementation at dosages of 0，500 and 2500 mg Vc／kg diets, respectively. All the turtles were weighed to get the initial average weight of each group at the beginning of the experiment, and then fed with experimental diets under 25℃±1℃. After 4 weeks, the water temperature was slowly reduced to 7℃ and all turtles were induced into hibernation. Six turtles per group were weighed and sampled with liver and kidney instantly. The rest turtles were also weighed. After 8 weeks hibernation, all the treatments were conducted as above. The liver Vc concentration, L- gulono -γ- lactone oxidase (GLO) activity of liver and kidney were determined by high pressure liquid chromatogram (HPLC). The results showed that Vc could be synthesized in the soft-shelled turtle’s kidney. The specific growth rate were not clearly influenced by dietary Vc supplementation. After 8 weeks hibernation, body weight of all groups decreased, but the specific growth rate within hibernation did not vary with Vc supplementation. At the beginning of hibernation, liver Vc concentration increased with increasing dietary Vc levels, but with no significant differences among all groups. After the hibernation, liver Vc concentration in Vc0, Vc2500 groups decreased significantly while that in Vc500 group did not reduce much. GLO activity of the kidney varied little after 8 weeks hibernation, and there was no obvious difference among all treatment groups. The results suggested that liver Vc consumed during hibernation. Neither Vc supplementation nor hibernation affected GLO activity significantly [ Acta Zoologica Sinica 54(2):309– 316, 2008].