| Piglet weaning is accompanied by the occurrence of intestinal inflammation,which forms a series of negative reactions in incomplete developed intestinal tract of piglets,such as intestinal mucosal injury,intestinal villi damage and intestinal wall injury and so on,affects the digestive and absorptive function of intestinal tract in piglets leads to sluggish growth,diarrhea and even death,and then brings great economicloss to swine industry.Seeking a functional active substance instead of antibiotics to promote growth and reduce the intestinal inflammation of weaned piglets caused by weaning has become a hot scientific issue.As a natural active substance,?-carotene has many functions,such as anti-oxidation,enhancing immunity,promoting tight junctions and activation of intestinal mucosal immunity.Therefore,?-carotene was chosen as a protective agent for intestinal inflammation to study the protective effects of ?-carotene on intestinal inflammation and its mechanism from the body and cell level.Thirty 28-days-old Junmu NO.1 weaned piglets were randomly divided into two groups,weighing and collect blood samples every two weeks to detection of immune and inflammatory related factors in serum.At the end of the six week feeding experiment,the intestinal samples were collected to detect the secretion of intestinal antibodies and the expression of the proinflammatory cytokine related gene by fluorescent quantitative PCR.The results show that feeding ?-carotene two weeks,the average daily gain of piglets was significantly higher than that of the control group(p<0.05),the ratio of feed to meat was significantly higher than that of the control group,Proinflammatory cytokine IL-1,IL-6,IFN-?,TNF-? levels were significantly lower than those in the control group(p<0.05).There was no significant change in the growth performance of beta carotene in the test group after 4-6 weeks,but the serum IgA and IL-2 was significantly higher than the control group(p<0.05),the serum NO was significantly lower than control group(p<0.05).?-carotene can also improve the jejunum villi morphology effectively of weaned piglets and significantly improve the relative expression of the immunoglobulin secretion related genes CCL25,IgA SC(p<0.05)in jejunum,and significantly decrease the relative genes expression of IL-6,IFN-?,TNF-? and NF-?B signaling pathway gene in the ileum(p<0.05).In vitro experiments,LPS-induced IPEC-J2 inflammation model were used to study the protective effects of ?-carotene,and the cell viability,apoptosis and NO content were observed to test the protective effect of ?-carotene,and through a comparative experiment with vitamin E,vitamin A and PDTC to research the relationship between the function of protective effects of inflammatory stress with the function of antioxidant,vitamin A sources and NF-?b protein.Finally,we use cell transfection technique to established a transfected MyD88 cell line to validation of the regulatory effect of ?-carotene on the NF-?b signaling pathway.The results showed that the protective effect of ?-carotene on IPEC-J2 cells inflammation was established,and the protective effect of ?-carotene on IPEC-J2 cell inflammation included by LPS was verified by cell viability,apoptosis and NO assay.Equally antioxidant capacity of Vitamin E and ?-carotene can significantly decrease the content of ROS induced by LPS in IPEC-J2 cells,IPEC-J2 cells could significantly increase antioxidant enzyme related genes superoxide dismutase(SOD),glutathione peroxidase(GPx)gene expression(p<0.05),but there are no significant differences between these two groups(p>0.05).Vitamin A and vitamin E also can inhibit the expression of proinflammatory cytokines of IPEC-J2 cells which induced by LPS,but the effect is significantly lower than ?-carotene.PDTC can significantly reduced the expression of NF-?b gene,and the inhibition effect was significantly higher than that of ?-carotene,when IPEC-J2 is co-treated with PDTC and ?-carotene,the inhibitory effect of ?-carotene on the expression of proinflammatory cytokines in LPS stressed IPEC-J2 cells was not significant.The protective effect of ?-carotene on the inflammatory of MyD88 transfected IPEC-J2 cell which induced by LPS was not obvious in the cell viability,the expression of inflammatory cytokines and the expression of NF-?b p65 protein.In conclusion,?-carotene can promote the growth of weaned piglets,enhance the immunity of the piglets and reduced intestinal inflammatory response which included by weaning.And pretreatment of ?-carotene can reduce the inflammatory damage induced by LPS in IPEC-J2 cells,and has a protective effect on intestinal cells.The inflammation protective effect of equally antioxidant capacity of Vitamin E and Vitamin A which equal to 2 times the concentration of ?-carotene was significantly lower than ?-carotene,and when the signal pathway of TLR4/MyD88/NF-?b was inhibited,the protective effect of ?-carotene on cell inflammation was not obvious.It indicates that ?-carotene may reduce intestinal cell inflammation by regulating the TLR4/MyD88/NF-?b signaling pathway. |
PDF Full Text Request