Effects Of Oxidized Pork On The Levels Of Blood Glucose,Blood Lipids And Gut Microbiota In Mice

The intake of red meat,especially processed red meat,is closely related to the risk of cardiovascular disease,diabetes and cancer such as colorectal cancer.The oxidation of pork protein caused by processing may be an important inducement of obesity and diabetes.The effect of different processing conditions on the oxidation of pork protein and the effects of different oxidation degree of pork on blood glucose,blood lipid,redox state,inflammation and gut microbiota in mice were investigated.we first determined the processing conditions of pork with low-oxidation and highoxidation degree,and investigated the effects of cooking pressure,temperature and time on protein oxidation.The results showed that the content of carbonyl and dityrosine(DT)in pork was the lowest,and the content of sulfhydryl group was the highest in pork under the vacuum condition at 70°C for 1 h.The oxidation of protein in pork was the lowest,so this condition was used as the preparation of low oxidized meat.However,under the conditions of high temperature and high pressure(121°C,0.3 Mpa)cooking for 1 h,the oxidation of protein in pork was significantly higher than that of low oxidized meat.Therefore,this condition was used as the preparation condition of high oxidized meat.Digestion of pepsin and trypsin in vitro was used to determine the digestibility of pork protein and the antioxidant activity of digestive products under low and high oxidation conditions.The results showed that compared with low oxidized meat,the digestibility of high oxidized meat in vitro decreased significantly(P<0.01),the carbonyl group increased significantly(P<0.05),the content of free sulfhydryl group decreased significantly(P<0.01),and the ability to scavenge ·OH and DPPH· was also weakened.Animal experiments were conducted to explore the effects of pork with different oxidation degree on the body health of mice.The results were as follows: after 12 th week,compared with the CON group,the body weight,rate of abdominal fat and testosterone and blood sugar increased significantly,the levels of MDA,DT,3-NT and AOPP in plasma,liver,ileum and colon increased,and the content of LPS and LBP in plasma increased in the HO group.Compared with the LO group,the rate of testosterone was increased,TC,LDL-C was increased significantly,HDL-C decreased significantly and casused dyslipidemia;the levels of T-AOC and CAT in plasma,liver,ileum and colon were decreased,and the level of ROS increased,and the gene expression of Nrf2,NQO1,HO-1 and PI3 K was down regulated,the gene expression of GSK-3? was up regulated and the redox state of the body was out of balance in the HO group.In addition,compared with LO group,the levels of LPS and LBP in the plasma increased,the levels of TNF-?,IL-6 and IL-1? in the liver,ileum and colon tissues increased,the level of IL-10 decreased,and the gene expression level of NF-?B was up regulated in the HO group.The results of HE staining in ileum and colon showed that long-term intake of high oxidized meat would cause inflammatory reaction.Moreover,the gene expression levels of caludin3,occludin and ZO-1 in the ileum were all down regulated in HO group,indicating that the intestinal epithelial cell barrier was damaged,the permeability was enhanced,the endotoxin was released into the blood and caused the inflammatory reaction in the body.16 S rRNA analysis of gut microbiota found that compared with the LO group,the gut microbiota structure was disturbed,and the lowest abundance of Akkermansia and Lactobacillus,the highest abundance of Mucispirillum in the gut microbiota of mice in the HO group.It may cause obesity and type 2 diabetes.The above results showed that cooking temperature,time and pressure had a significant effect on the oxidation degree of pork protein,the high degree oxidation of the pork protein in vitro digestibility decreased,and the antioxidant and free radical scavenging ability of digestive products was reduced.Long-term ingestion of high-oxidized pork might lead to the imbalance of the redox state of the body,the increase of blood glucose and the disorder of blood lipid metabolism,the disorder of the gut microbiota,the damage of the intestinal barrier function,the entry of LPS into the blood,the increase of inflammatory cytokines and the inflammation of the body.