Effects Of Supplements Of Rumen-protected Folic Acid On Reproductive Hormones And Biochemical Indexes Of Ewes

In recent years, insufficience of folic acid in diet had affected the growth performance, reproduction and lactation. However, the reports on status of folic acid in adult ewes were very scarce. The objective of the study was investigate effects of supplements of different levels of rumen-protected folic acid on reproductive hormones in estrus cycle of ewes, serum biochemical indexes、immune indexes and antioxidant indexes during different gestation periods. Forty eight healthy Dorperx small Tailed Han ewes with 2～3-year-old, similar body weight (45±3 kg) were randomly divided into 4 groups. Control group (A) were fed on a basal diet, treatment groups (B, C, D) fed on a basal diet with adding 0.75 mg,2.25 mg and 3.75 mg folic acid every day respectively. Blood samples were collected at 3 h,6 h,9 h,12 h and 24 h after folic acid were fed for two consecutive days to investigate the effects of supplements of rumen-protected folic acid on serum folic acid and homocysteine concentrations. After estrus synchronization, six ewes in each group were selected randomly to collect blood samples in 1 day before vaginal suppository withdrawal,0 d,1 d,2 d,6 d,10 d,14 d,18 d,19 d,20 d and 21 d (the first day of next estrus cycle) in estrus cycle. Blood samples were collected to detect the concentrations of FSH、LH、E2 and P. Blood samples were collected to detect serum biochemical indexes, immune indexes and the antioxidant indexes in the 30 th,60 th and 120 th days during gestation. The results showed that:(1) During 3h～12h, serum folic acid concentrations was reduced gradually in each group; During 12h～24h, serum folic acid concentrations was increased to highest level.in each group in a day. With folic acid supplementation, homocysteine concentration in 3.75 mg/d group was increased significantly than control group (P< 0.05).(2) LH had two peaks on the first day and the twentieth day in estrus cycle, the second peak had a significant difference (P< 0.05). P had a peak in the fourteenth day, the peak of groups with supplements of folic acid was more later than that of control group.(3) TP content in the group of 2.25 mg/d folic acid supplementation was increased significantly in 30 th day (P< 0.05), meanwhile, SUN content was increased significantly in the group with supplementation of 0.75 mg/d folic acid (P< 0.05). In the 60 th day, TP and GLB content in the group of 2.25 mg/d folic acid supplementation was higher than that in control group (P< 0.05), while GLU concentrations in groups with folic acid supplementation was lower than that in control group (P< 0.05) In 120 th day, ALB content in the group with supplementation of 2.25 mg/d folic acid was increased significantly (P< 0.05)(4) In the 60th day, IgA content in the group with supplementation of 3.75 mg/d folic acid was increased significantly (P< 0.05), IgG content in the group with supplementation of 2.25 mg/d folic acid was increased significantly (P< 0.05), IgM content in the group with supplementation of 2.25 mg/d folic acid was increased significantly than that in group with supplementation of 3.75 mg/d folic acid and that in control group (P< 0.05). In the 30th day, SOD activity in the group with supplementation of 2.25 mg/d folic acid was increased significantly than that in control group (P< 0.05). In the 60 th day, SOD activity in the group with supplementation of 0.75 mg/d folic acid was increased significantly (P< 0.05)Conclusion:The appropriate supplementation of rumen-protected folic acid was 2.25 mg/d for pregnant Dorperx small Tailed Han ewes.