Effect Of Dietary Wine Grape Pomace On Reproductive Performance, Antioxidant Capacity Of Testis And Epididymis In Ram

Restriction of activity in stall-feeding condition, which can cause stress, will affect the reproductive performance of sheep in some extent. There are a large amount of polyphenols in grape pomace and seed, which have the function of resisting oxidative stress. The present study was performed to examine the effect of grape pomace supplementation to base diet on reproductive performance, serum and testicular antioxidant capacity, Cu/ZnSOD, CAT, GPX4 and Nrf2 gene and protein expression in testis and epididymis of ram.A total of 30 hybrid 5-month-old Dorper ((?))×Small Tail Han sheep ((?)) F1 male lambs weighting around 25kg were randomly divided into 5 groups with 6 lambs per group. Lambs in one of groups were raised freely, and the other four groups were raised separately. Lambs in free group were fed with a base diet but no grape pomace, the other lambs in separated groups were fed with diets supplemented with grape pomace at 0%,5%,10%,20% on a dry weight basis (group 0%, group 5%, group 10%, group 20%) respectively. The period of animal feeding was 80d. All lambs were slaughtered after the feeding experiment and sampled. Epididymal sperm suspension were made for sperm density and motility analysis; antioxidant levels in serum and testicles were tested by ELISA; Relative Cu/ZnSOD, CAT, GPx4, Nrf2 mRNA and protein expression in testis and epididymis tissue was analyzed using QRT-PCR and Western blotting technology. The results are as follows:1. Compared with free group, MDA level of serum in separated group with 0% wine grape pomace was significantly increased (P<0.05), MDA and ROS level of testicles in separated group with 0% wine grape pomace were significantly increased (P<0.01), showing that separated-raising system could cause oxidative damage to lambs.2. Testis weight of lambs was significantly decreased (P<0.05), and the organ coefficient of testis had a trend to be lower (P=0.06) in separated group with 0% wine grape pomace. Under separated-raising system, epididymal sperm density and motility were largely declined (P<0.05 and P<0.01, respectively), which indicated that separated-raising system could affect the reproductive performance of ram in some extent. While, epididymal sperm density and motility were signally increased in wine grape pomace added groups (P<0.05), showing that wine grape pomace could improve the reproductive performance of ram.3. Serum T-AOC and CAT enzyme activity were improved significantly (P<0.05 and P<0.01, respectively) in wine grape pomace added groups, indicating that wine grape pomace was conducive to serum antioxidant capacity of ram.4. Testicular tissue MDA content decreased significantly (P<0.01); SOD, CAT and GSH-Px activity were significantly improved (P<0.01, P<0.05 and P<0.01, respectively) in wine grape pomace added groups. Wine grape pomace had no significant effect on relative Cu-ZnSOD, GPx4, CAT and Nrf2 mRNA expression level in testis and epididymis of ram, except that a few genes had a trend of increasing. Relative Cu-ZnSOD, GPx4 and CAT protein contents in testis, relative Cu-ZnSOD and CAT protein contents in epididymis caput, relative Cu-ZnSOD and Nrf2 protein contents in epididymis corpus, relative Cu-ZnSOD, GPx4 and Nrf2 protein contents in epididymis cauda were significantly increased (P<0.05) in wine grape pomace added groups.In conclusion, wine grape pomace could improved the reproductive performance, antioxidant level in serum, testis and epididymis tissue of separated-raising lambs.