Effect Of Nano-zinc Diets On Sheep Semen Quality And Gonads Cu-ZnSOD Expression

This experiment was designed to investigate the effects of nano-zinc on:(1) the semen quality and seminal plasma antioxidant enzyme activity;(2) the expression pattern of Cu-ZnSOD in testicles and epididymis, and (3) the localization of Cu-ZnSOD in testicles and epididymis.Total16Jin zhong ram were randomly selected and assigned into4groups, and fed with the experimental diet supplemented with0(control),50mg.g-1,100mg.kg-1,150mg.kg-1DM nano-zinc for90d. At the end of experiment, semen was collected and semen quality and seminal plasma antioxidant enzyme activity were measured. Testicles epididymis samples were collected and the mRNA and protein expressions of Cu-ZnSOD in testicles pididymis were investigated using QRT-PCR, immunohistochemistry and western-blotting techniques.The results of were as follows:(1) Addition of both50mg·kg-1,100mg·kg-1zinc could significantly improve sperm density, reduced sperm malformation rate and improve sheep seminal plasma SOD, GSH-Px activity and T-AOC, lower seminal plasma MDA levels (P<0.05), indicating that certain amount of zinc could improve sperm quality and seminal plasma antioxidant enzyme activity.(2)50mg·kg-1and100mg-kg’1zinc could elevated the Cu-ZnSOD gene expression in both mRNA expression and protein level, compared with control group and150mg·kg-1zinc levels groups, which suggested that zinc could regulate Cu-ZnSOD gene expression and optical amount of nano-zinc could promote the expression of Cu-ZnSOD gene and protein in the testis and epididymis.(3) Immunohistochemistry staining showed that Cu-ZnSOD was localized on testicular germ cells and stromal cells. In addition, Cu-ZnSOD could also be found in the epididymal head and body pseudostratified epithelial primary cells and ciliated cells. The connective tissue between the lumen and epididymal tube also found positive signals. Cu-ZnSOD in epididymal tail was mainly expressed in the epithelium cells. Our data showed that Cu-ZnSOD plays an important role in spermatogenesis and sperm maturation.