| The cecum is an important part of the gastrointestinal tract and is an important fermentation organs of ruminants.After the diet is fed,it arrived the hindgut via the forestomach and duodenum,and is fermented in the hindgut.There are also a series of metabolites such as fatty acids produced in the cecum.When the diet composition is changed,excessive fatty acids are produced which can cause the metabolism disorders and the abnormal energy supply in ruminants,then the inflammation response may appear.We designed the experiment to investigated the effects of high-concentrate diets on the inflammation which caused by the short fatty acids activating the G-protein coupled receptors(GPR41?GPR43);and we also investigated the regulatory effect of high-concentrate diets with sodium butyrate on the inflammation mediated by SCFAs;finally on this basis,we investigated the effct of sodium butyrate on the epigenetic mechanisms associated with the expression of the key receptors——GPR41/43genes.1 Effects of high-concentrate diets on the inflammation mediated by SCFAs activating GPR41/43in cecum of lactating goatsTrail 1:12 saanen goats were selected as the experiment animals and divided into 2 groups randomly.One group(LC)fed with low-concentrate diet(concentrate:roughage=4:6,n=6,it was composed of 40%concentrate diet and 60%roughage diet)as control,and the other group(HC)fed with high-concentrate diet(concentrate:roughage=6:4,n=6,it was composed of 60%concentrate diet and 40%roughage diet)as treatment.After 10 weeks of feeding,rumen liquid,milk,cecum tissues and its intestinal contents were sampled 5 then detected by gas chromatography,Western blot,RT-qPCR to analyze the expression of genes(the key genes of GPR41,GPR43,p38 MAPK,ERK1/2 and the related inflammatory genes of IL-la,IL-1?,IL-6,IL-8,IL-10,TNF-?,CCL5,CCL20,CXCL10,CXCL13,MMP9,MMP13,zo-1 and Occludin et al.),proteins(GPR41,GPR43 and p38 MAPK,ERK1/2)and SCFAs and milk concentration,and pH value.Compared with LC group,the results showed the pH values of rumen liquid and the cecum tract were decreased in HC group;the acetate,propionate and butyrate concentration in cecum was increased significantly;the expressions of GPR41/43 and p38 MAPK,ERK1/2 genes and proteins were upregulated significantly;the related inflammatory cytokine genes(IL-la,IL-1?,TNF-?,IL-6,IL-8 and IL-10)and chemokine genes(CCL5,CCL20,CXCL10,CXCL13,MMP9 and MMP13 et al.)were increased significantly,the expression of zo-1 and Occludin genes were downregulated;and compared with LC group,the milk production was decreased in HC group,the milk protein and lactose concentration aslo was decreased.It is suggested that high concentrate diet can cause the fermentation in the rumen and the cecum to produce excessive SCFAs,which made the pH values in the rumen and the cecum were decreased and activited GPR41/43 mediating the inflammatory response in the cecum of lactating goats,finally it led to the mik production of lactating gaots was decreased.2 Regulatory effect of sodium butyrate on the inflammation mediated by SCFAs activiting GPR41/43Trail 2:12 saanen goats were selected as the experiment animals and divided into 2 groups randomly.one group(HC)fed with high-concentrate diet(concentrate:roughage=6:4,n=6,it was composed of 60%concentrate diet and 40%roughage diet)as treatment,and the other group(HCB)fed with high-concentrate diet supplemented with sodium butyrate(concentrate:roughage=6:4,n=6,it was composed of 60%concentrate diet and 40%roughage diet)as regulatory group.After 10 weeks of feeding,rumen liquid,milk,cecum tissues and its intestinal contents were sampled,then detected by gas chromatography,Western blot,RT-qPCR to analyze the expression of genes(the key genes of GPR41,GPR43,p38 MAPK,ERK1/2 and the related inflammatory genes,chemokines and other related cytokines,proteins(GPR41,GPR43 and p38 MAPK,ERK1/2)and SCFAs and milk concentration,and pH value.The results showed:Compared with HC group,acetate,propionate concentration were decreased significantly,butyrate were increased,and the total SCFAs concentration was increased in HCB group;rumen pH value was higher but cecum pH value did not change significantly in HCB;we aslo detected that in the HCB the expression of GPR41/43 and p38 MAPK,ERK1/2 genes and proteins were downregulated;the expression of IL-1?,IL-6,IL-8,TNF-? genes were decreased significantly,IL-10 gene was increased,the expression of CCL5,CXCL10,CXCL13,MMP9 and MMP13 were decreased,CCL20 was decreased but did not changed significantly;the expression of zo-1 and Occludin were upregulated;the milk production was also decreased in the HCB group.It suggested that sodium butyrate can affect the SCFAs composition in cecum,and plays a role in regulating the inflammation mediated by SCFAs activiting GPR41/43 in cecum of lactating goats,it can reduce the effect of inflammatory response on the milk production of lactating goats consequently.3 Effects of high-concentrate diet and the sodium butyrate on the epigenetic mechanisms of GPR41/43 in the SCFAs-GPR41/43 pathwaysTrail 3:18 saanen goats were selected as the experiment animals and divided into 3 groups randomly.one group(LC)fed with low-concentrate diet(concentrate:roughage=4:6,n=6,it was composed of 60%concentrate diet and 40%roughage diet)as control,one group(HC)fed with high-concentrate diet(concentrate:roughage=6:4,n=6,it was composed of 60%concentrate diet and 40%roughage diet)as treatment,and the final group(HCB)fed with high-concentrate diet supplemented with sodium butyrate(concentrate:roughage=6:4,n=6,it was composed of 60%concentrate diet and 40%roughage diet)as regulatory group.After 10 weeks of feeding,cecum tissues were sampled for DNA metylation and CHART-PCR analysis.On the basis of the trail.1 and trail 2,high-concentration diet fed can upregulate the expression of the key GPR41/43 genes and proteins,however,sodium butyrate downregulate the expression of GPR41/43 genes and proteins affected by the high-concentrate diet.Therefore,this study further revealed the effect of high-concentrate diet and sodium butyrate on the epigenetic mechanism of GPR41/43 of the SCFAs-GPR41/43 pathways in cecum.The results revealed:the change trend of the DNA methylation rate and the degree of chromatin compaction of GPR41,GPR43 promoter regions in both HC and HCB group were consistent with the shift of their mRNA expression respectively;the DNA methylation rate and the degree of chromatin compaction of GPR41,GPR43 promoter regions in the HCB group were higher than in the HC group,but were lower than in the LC group.It displayed that after fed the high-concentrate diet,the DNA methylation rate and the degree of chromatin compaction of GPR41/43 promoter regions were reduced,which were conductive to GPR41/43 mRNA expression,and sodium butyrate can improve the low-level of DNA methylation rate and chromatin compaction of GPR41/43 promoter regions caused by long-term high-concentrate diet feedings.It further suggested that epigenetic mechanisms are involved in the expression of GPR41/43 in SCFAs-GPR41/43 pathways during the sodium butyrate treatment,then modulate the expression of the downstream cytokines to mediate the inflammatory response. |
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