The 60 juvenile soft-shelled turtles ( Pelodiscus sinensis
) obtained from a commercial farm were acclimated in laboratory for three weeks.The five groups juvenile turtles [one control group (C) and four experimented groups (I,II,III and IV)] were fed with Vc
supplementation at the dosages of 0 and 0,250 and 50,2 500 and 50,250 and 250,2 500 and 250 mg/kg diets,respectively.There were two replicates per group.After feeding 4 weeks,half turtles per group were treat with acid-stress for 24 h.The blood in turtles were collected,and the percentage phagocytic rate of blood cell was analyzed by counting under microscope;serum bacteriolytic activity,bactericidal activity,levels of complement C3 and C4 were analyzed by transmission colorimetric method.The results showed:1)the phagocytic rates of blood cell in stressed C significantly lowered compared with non-stressed C,while there were no significant changes in the other four groups of I-IV between stressed and non-stressed turtles;serum bacteriolytic activity and the level of complement C3 in the stressed C and I significantly declined,while there were no significant changes in II-IV compared with non-stress groups.Serum bactericidal activity in all stressed groups lowered (the three groups of C,II and IV tremendously significantly lowered,and I and III significantly lowered).The levels of complement C4 in the stressed three groups of C,II and III were significantly declined,while the other stressed two groups of II and IV had no significant change compared with non-stressed ones.2)Among of the acid stressed juvenile turtles,the phagocytic rate of blood cell,serum bacteriolytic activity,bactericidal activity and level of complement C3 in I-IV were significantly higher than that in C,and IB was significantly higher than the other four groups.The bactericidal activity in II was higher than both I and III.The level of complement C4 in C was significantly lower than those in I-IV,while there was no significant difference among the four groups of I-IV.The combination of Vc
had interaction effects on the phagocytic rate of blood cell,serum bacteriolytic activity,bactericidal activity and the level of complement C3 after acid stress,while no interaction effect of the two vitamins on complement C4 was observed.The results suggested that the combination of Vc
significantly improved anti-acid stress ability in soft-shelled turtles,and alleviated or partly alleviate the adverse effects caused due to acid stress.