Investigation On Diarrhea Incidence And Anti-inflammatory Effect Of Angiotensin Converting Enzyme 2(ACE2)in Nursery Swines On A Porcine Shed

The problem of intestinal diseases has always been a thorny problem in intensive culture.It is a common clinical symptom of many diseases,and it is also the disease most susceptible to nursery swines during the breeding process.The ACE2-Ang 1-7-Mas receptor axis has been shown to have anti-inflammatory effects in many studies,while ACE2 can promote expression of the neutral amino acid transporter B0AT1 in the intestine.Therefore,this article through a practical survey on the actual production of nursery swines in a porcine shed in Jiangsu,combined with laboratory research,to make some supplements for the prevention and control of nursery swines and research data on the RAS system.The study includes the following two aspects:Series I Investigation on diarrhea incidence of nursery swines in a farm in Jiangsu and its pathological analysisIn the experiment,600 nursery swines were observed for 10 days,and the swine house temperature,diarrhea rate,and mortality rate were counted.Four swines with diarrhea and normal healthy swines were selected.Blood were collected from hearts and tissue samples were slaughtered.The following experiments were performed:1)Determination of blood glucose(GLU),albumin(ALB),globulin(GLB),aspartate aminotransferase(AST),alanine aminotransferase(ALT),alkaline phosphatase(ALP),lactate dehydrogenase(LDH),glycerol Triester(TG);2)Making histopathological sections and observing the pathological changes of the stomach,duodenum,jejunum,ileum,colon,etc;3)The activity of digestive tract enzymes such as pepsin,trypsin,amylase,and cholecystokinin in gastrointestinal chyme were detected by ELISA.Results:1)During the 10-day period,the noon temperature was basically maintained at 28.99?,the night temperature averaged 27.14?,the diarrhea rate of nursery swines was 6.92%,the mortality rate was 0.24%,and the diarrhea rate was high;2)The blood-related biochemical indicators of diarrhea swines were Significantly changed,GLB,AST,and LDH levels were significantly up regulated(37.37±3.99 vs 22.18±1.02,144.75±17.44 vs 44.33±4.81,1476.33±319.81 vs 535.33±11.84,P<0.05),GLU and ALP was significantly down regulated(4.74±0.63 vs 6.67±0.13,8.5±3.62 vs 44.25±11.53,P<0.05);3)Pathological observations revealed that diarrhea swines had gastric tissue epithelial damage and shedding of duodenal intestinal mucosa.Intestinal gland cell proliferation,intestinal crypt thickening;jejunal intestinal villi necrosis,mucosal epithelial cells necrosis,intestinal epithelial cell proliferation;ileum,colon,intestinal gland cells were significantly proliferative;lung,lymph nodes,liver showed significant pathological changes;4)Pepsin activity(P<0.05),gastroduodenal contents of trypsin activity(P<0.01),amylase activity(P<0.05)and other digestive enzyme activities were significantly reduced in diarrhea swines' intestinal diarrhea.,Cholecystokinin content significantly reduced(P<0.01).The results suggest that:The swines with intestinal diarrhea in the swines developed obvious proliferative inflammation.Series II The Effect and Mechanism of ACE2 in Intestinal Proliferative Inflammation in Nursery SwinesThe experiment was conducted on a 49-day-old nursery swine with chronic proliferative enteritis.The following experiments were performed:1)Detection of RAS system:expression of ACE2,Mas receptor mRNA in duodenum and ileum of nursery swines,and Ang II,Angl-7;2)Comparative analysis of TNF-?,IL-1? and IL-10 mRNA expression in duodenum and ileum;3)Comparative analysis of B0AT1 and SGLT-1 in duodenum and ileum,mRNA expression of GLUT-2 and PEPT-1 transporter.Results:1)In diarrhea group,compared with control swines,the mRNA expression of ACE2 and Mas receptors in the RAS system in the duodenum was significantly decreased(P<0.05),and the content of Angl-7 was significantly decreased(714.91±15.41 vs 814.83±48.43,P<0.05).The related transporter:B0AT1,SGLT-1,GLUT-2,PEPT-1 mRNA expression was also significantly decreased(P<0.05),but the Ang ? content in the duodenal tissue was significant increased(292.14±10.02 vs 240.28±2.89,P<0.05),and its inflammation-related factors:TNF-?,IL-1? mRNA expression was also significantly up regulated(P<0.05);2)diarrhea group compared with the control swines The expression of Mas receptor mRNA in the ileum was significantly down regulated(P<0.05),but the levels of ACE2,Angl-7 and Ang II were not significantly changed.Tissue related inflammatory factors:TNF-?,IL-1?mRNA Expression was significantly up regulated(P<0.05),but IL-10 expression was significantly down regulated(P<0.05);mRNA expression of transporter related carriers:B0AT1,SGLT-1,GLUT-2,and PEPT-1 were all significantly down regulated in ileal tissues.(P<0.05);Conclusion:The development of inflammation in the duodenum is accompanied by an increase in the level of Ang II,The expression of ACE2 axis was overall in a disadvantage,the expression of pro-inflammatory cytokines was significantly increased,the expression of IL-10 mRNA was significantly inhibited,and the transport and absorption of substances was affected.During the development of inflammation in the ileum,ACE2 levels increase,and the downstream Angl-7-Mas receptors are at a disadvantage.The expression of pro-inflammatory cytokines is significantly increased,but the expression of IL-10 mRNA is increased,and the absorption and translocation of substances is severely affected.