Effects And Mechanisms Of Dietary Wine Grape Pomace Supplementation On Jejunal Structure And Epithelial Cell Apoptosis In Lambs

Oxidative stress is a widespread phenomenon during animal production,affecting the normal function of many organs and tissues,especially in the intestines.Wine Grape Pomace(WGP)is an effective antioxidant due to polyphenols component.The objective of this study was to investigate the effects of dietary WGP supplementation on the morphological,apoptosis and antioxidant activity in lamb jejunum.Eighteen lambs(25.0 ± 0.2 kg)were randomly selected and equally divided into 3 groups,and offered diet containing different levels of WGP(0%,5% and 10%).Morphological differences of sheep jejunum were identified by H&E staining.The apoptotic rate and changes of apoptosis-related genes of jejunal epithelium cells were detected by TUNEL,immunohistochemistry,q RT-PCR and Western blotting.The total antioxidant capacity of the jejunum and the changes of antioxidant-related proteins were detected by ELISA and Western blotting.The results were as follows:1.5% dietary WGP supplementation could significantly reduce the depth of jejunal crypt(P <0.05),while 10% dietary WGP supplementation can significantly reduce the height of villi(P <0.05).The ratio of villus height and crypt depth in WGP-added groups significantly increased(P < 0.05),but there was no significant difference between two treated groups.Morphological observations showed that the jejunal epithelial structure of the WGP-added group was clearer and complete.2.Dietary WGP supplementation significantly reduced the number of apoptotic cells in jejunal epithelium of sheep(P <0.05),and there was a negative correlation between apoptotic rate and content of WGP(P <0.05).The results of immunohistochemistry showed that protein content of Caspase 3 and Caspase 9 were significantly decreased in the WGP-added group,compared with control group(P <0.05).Caspase 8 content in the 10% WGP-treated group was significantly lower than that in the control group(P <0.05).Accordingly,the results of WB and q RT-PCR showed that the apoptotic genes expression were significantly decreased in the WGP-added group.Meanwhile,the addition of 5% and 10% WGP increased the abundance of anti-apoptotic protein Bcl-2(P <0.05)and decreased the pro-apoptotic protein BAX abundance(P <0.05).In addition,the p-ATM protein abundance was significantly reduced in the WGP-treated group(P < 0.05).3.WGP significantly reduce the concentration of reactive oxygen species(ROS)and malondialdehyde(MAD)(P < 0.05),increased the total antioxidant capacity of jejunum and the CAT,Gpx4 and SOD activities(P < 0.05).WB results showed that WGP significantly increased the abundance of antioxidant proteins CAT,Gpx4 and SOD(P <0.05).In conclusion,WGP enhanced the antioxidant capacity of sheep jejunum,alleviated the injury of oxidative stress on sheep jejunal epithelial cell apoptosis.Meanwhile,WGP increased the ratio of villus height and crypt depth,and improved jejunal epithelial structure.