| Liver is an important tissue and organ of piglets.Early weaning stress can induce liver damage and intestinal microbiota imbalance in piglets.Alpha tocopherol is the most bioactive component of vitamin E with strong antioxidant properties.In order to investigate the effect of dietary α-tocopherol on alleviating oxidative stress and acute liver injury in the liver of weanling piglets,as well as its effect on the intestinal microorganisms of weanling piglets,the following experiments were carried out:Experiment 1: 72 heads 21 days old×Large binary weaned piglets(with similar body weight and half male and half female)were randomly divided into a control group and an experimental group.The control group was fed a basic diet(Ctrl group),while the experimental group was fed a basic diet+75 mg/kg α-tocopherol(TP group),6 replicates per treatment,6 piglets per replicate,experimental period of 21 days.After feeding,6 piglets were randomly selected from each group for slaughter.Collect piglet serum,liver,and rectal contents for detection.The main results are as follows:(1)Growth performance and liver physiological indicators: The body weight,liver weight,and liver index of piglets in the TP group were significantly increased(P < 0.05).(2)Antioxidant indicators: Compared with the Ctrl group,the TP group significantly increased the levels of T-AOC and CAT in the serum of piglets(P< 0.05),while the MDA content significantly decreased(P < 0.05).(3)Liver tissue sections(H&E staining)and liver functional enzyme indicators: The activity of AST in the TP group was significantly decreased(P < 0.05).However,H&E tissue sections showed no significant infiltration of inflammatory cells in the liver tissues of piglets in both the Ctrl and TP groups.(4)Inflammatory factor indicators: The m RNA expression level of TNF-α in the liver of TP group was significantly decreased(P < 0.05),while the m RNA expression level of IL-10 was significantly increased(P < 0.05).(5)Nrf2 related genes and protein expression levels: There was a difference of m RAN expression levels in liver of piglets of Nrf2 in these two groups where the expression of TP group is apparently lower than that of the Ctrl group(P < 0.05).The immunofluorescence staining results showed that high expression of Nrf2 protein was observed in the liver nuclei of the Ctrl group piglets.The Nrf2 protein in the TP group was low expressed in the liver nuclei of piglets.(6)The 16 S r DNA amplicon sequencing results showed that at the genus level,α-tocopherol significantly reduced the abundance of Prevotella(P < 0.05).At the level of species,α-tocopherol significantly reduced the abundance of Collinsella＿aerofaciens and Bulleidia＿p-1630-c5(P < 0.05).(7)The correlation analysis between gut microbiota and detection indicators showed that Prevotella(P < 0.05)is positively correlated with liver function indicator AST,Cyanobacterium(P <0.05)is positively correlated with inflammatory factor IL-10.The results indicate that adding 75 mg/kg to the diet α-tocopherol can improve the antioxidant capacity and weight of weaned piglets,reduce liver function enzyme activity and inflammatory factor expression,improve liver damage caused by weaning stress,maintain intestinal microbial diversity,and reduce the abundance of harmful bacteria.Experiment 2: On the morning of the 43 rd day of age(the 22 nd day of the trial),6 piglets were randomly selected from the Ctrl and TP groups to receive intraperitoneal injection of LPS solution(100 μg/kg BW),establish acute injury models,including CL group and TPL group.CC group and TPC group followed the end-of-trial data of Ctrl group and TP group in experiment 1,respectively.After injecting LPS solution for 4 hours,all 6 piglets in the CL and TPL groups were slaughtered.The experimental results are as follows:(1)Antioxidant indicators: There was a significant comparison.As for the levels of T-AOC,CAT,and SOD in the serum of piglets,the CL group was obviously lower than CC group(P < 0.05),while the levels of MDA and DAO,the former was significantly higher than CC group(P < 0.05).Compared with the CL group,the T-AOC content in the serum of piglets in the TPL group had a rise(P < 0.05),while the MDA content took on a significant decrease(P < 0.05).(2)Liver tissue H&E and liver function indicators: In the CL group,there was an increase in white blood cells in the liver sinusoids and a significant infiltration of inflammatory cells in the stroma.There was a small amount of inflammatory cell infiltration in the liver cells of TPL group piglets,and the cell morphology was relatively intact.The activity of ALP in the piglets in the TPL group was lower than in the CL group(P < 0.05).(3)Nrf2 protein: In the CL group,Nrf2 was highly expressed in the nucleus of piglet liver cells.In TPL group,the expression level of Nrf2 protein in the nucleus of liver cells of piglets decreased.(4)The 16 S r DNA amplicon sequencing results showed that the community richness index Chao1 in the CL group was significantly decreased(P < 0.05).In terms of genus level,the relative abundance of Ochrobactrum,Brevibacterium and Oceanobacillus in CL group presented largely higher than that in CC group(P < 0.05).What’s more,as for species level,the abundance of Oceanobacillus＿profundus in the CL group was higher with the comparison of CC group(P< 0.05).The abundance of Collinsella＿aerofaciens in the TPL group was significantly lower than that in the CC group(P < 0.05),and the abundance of Bulleidia＿p-1630-c5 in the TPL group was significantly lower than that in the CL group(P < 0.05).(5)The correlation analysis of intestinal microbiota and detection indexes showed that Streptococcus(P < 0.05)was positively correlated with the ALP,a liver function enzyme index.The results showed that intraperitoneal injection of LPS solution can cause acute liver injury of piglets.Per-feeding α-tocopherol can improve the antioxidant capacity of weanling piglets,regulate the composition of microbial flora,and effectively prevent liver damage caused by acute stress.Conclusion:The supplementation of 75 mg/kg α-tocopherol in the diet of weaned piglets can improve the antioxidant capacity and weight of weaned piglets,reduce liver function enzyme activity and inflammatory factor expression.Feeding α-tocopherol can effectively prevent liver damage caused by acute stress,alter the composition of rectal microbial flora,and reduce the abundance of harmful bacteria. |
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