Regulative Effect Of Flaxseed Oil On Intestinal And Liver Injury Of Piglets After Lipopolysaccharide Challenge

The studies were done to investigate the effect of dietary supplementation of 5%flaxseed oil on fatty acid composition,morphology and function,mRNA expression of key genes in nucleotide binding oligomerization domain protein(NOD)and toll-like receptor 4(TLR4)signaling pathways in intestine and liver of weanling piglets subjected to lipopoly saccharide(LPS)injection.Our aims were to elucidate if dietary flaxseed oil addition could exert a protective effect on intestine and liver damage of weanling pigs.A total of 24 weanling pigs(average body weight 9.15±0.8 kg)were chosen in a 2 × 2 factorial design experiment.The two main factors were dietary treatment and immunological challenge.Four treatment groups included:1)5%corn oil+ saline,2)5%flaxseed oil + saline,3)5%corn oil + LPS,and 4)5%flaxseed oil + LPS,respectively.After 21-d feeding with flaxseed oil or corn oil-supplemented diets,the piglets in group 1 and 2 were injected intraperitoneally with saline,and the piglets in group 3 and 4 were injected intraperitoneally with LPS at 100 ?g/kg body weight(BW).Blood samples were harvested after 2 or 4 h saline or LPS administration,and then the piglets were slaughtered for collection of intestinal and liver samples.The aim of the experiment 1 was to elucidate if dietary flaxseed oil addition could exert a protective effect on intestine damage of weanling pigs.The results showed that:(1)Flaxseed oil supplementation resulted in increase of total n-3 polyunsaturated fatty acid(PUFA),alpha-linolenic acid(ALA)and eicosapentaenoic acid(EPA)in intestinal mucosa(P<0.001).(2)Flaxseed oil supplementation had no effect on growth performance of weaned piglets.(3)Flaxseed oil had no effect on intestinal morphology.(4)Flaxseed oil improved intestinal digestive function indicated by increased activities of jejunal lactase and ileal maltase(P<0.05).(5)Flaxseed oil down-regulated protein abundance of jejunal heat shock protein 70(HSP70)(P<0.05).(6)Flaxseed oil decreased mRNA abundance of intestinal TLR4.NOD1,NOD2 and receptor-interacting serine/threonine-protein kinase 2(RIPK2)(P<0.05).The results indicate that flaxseed oil addition results in enrichment of n-3 PUFA in intestine,inhibits the TLR4 and NOD signaling pathways,and thus exerts a slight protective effect on intestinal digestive function.However,flaxseed oil does not exert a benefical effect on intestinal morphology.The aim of the experiment 2 was to explore if dietary flaxseed oil supplementation could play a protective role on intestine damage of weanling pigs.The results showed that:(1)Flaxseed oil supplementation resulted in increase of total n-3 PUFA,ALA and EPA in liver(P<0.001).(2)Flaxseed oil alleviated the damage of liver morphology induced by LPS.(3)Flaxseed oil alleviated the LPS-induced damage of hepatic function indicated by decreased activities of serum ALT and AST after 2 and 4 h LPS challenge,as well as decreased activity of serum AKP after 4 h LPS challenge(P<0.05).(4)Flaxseed oil reduced mRNA expression of liver tumor necrosis factor-?(TNF-a)and cyclooxygenase 2(COX2),and protein expression of liver HSP70(P<0.05).(5)Flaxseed oil decreased mRNA expressions of liver TLR4,myeloid differentiation factor 88(MyD88),TNF-a receptor-associated factor 6(TRAF6),suppressor of cytokine signaling 1(SOCS1).NOD1 and RIPK2(P<0.05).and increased mRNA expression of liver single immunoglobulin IL-1 R-related molecule(SIGIRR)(P<0.05).The results indicate that flaxseed oil supplementation results in enrichment of n-3 PUFA in liver,inhibits the TLR4 and NOD signaling pathways and inflammtory response,and thus exerts protective effects on liver morphology and function damage induced by LPS injection.