Investigation And Vaginal Mucous Microflora Analysis Of Endometritis In Sows In Three Farms

In modern pig production,endometritis has become one of the important factors restricting the production level of sows.Because the etiology of sow endometritis is complex and the cure rate is low,it is helpful to analyze and find out the etiology of sow endometritis.The purpose of the study was to investigate the incidence of endometritis in pig farms,proinflammatory cytokines and vaginal mucous microflora of infected sows.The study was divided into the following three parts:1.Investigation of the incidence of endometritis in pig farms.A pig farm from Linfen(201gilts)and Xinzhou(152 gilts)in Shanxi Province and a pig farm in Miyun,Beijing(100 gilts and 975 sows in 6 batches)were investigated,random visits,questionnaires,access to sow files,inquiry to resident veterinarians and other methods were used to investigate the incidence of endometritis.The results showed that the intrauterine incidence rates of gilts in Linfen,Shanxi,Xinzhou and Beijing were 8.95%,8.52% and 8.00%,respectively.The nonpregnancy rates of gilts were 22.22%,30.76% and 25.00%,respectively.A pig farm in Miyun,Beijing,a follow-up survey on the incidence of endometritis in six batches of transparous sows showed that the incidence of endometritis in batches 1 to 6 was 19.12%,19.04%,15.32%,17.51%,18.12% and 18.35%,respectively,with an average incidence of18.05%.There was no significant difference in the incidence of endometritis among the six batches of sows(P>0.05).The prevalence of abnormal parturient sows was higher than that of normal parturient sows(P<0.01);The weaning estrus rate and pregnancy rate of healthy sows were higher than those of diseased sows(P<0.01).2.Serum cytokine analysis of healthy sows and sows with endometritis.Blood samples were collected from the anterior vena cava of 20 healthy sows(postpartum 5d and postweaning 4d)and sows with endometritis(lactating sows with still exudated inflammatory secretions 5 days after delivery and estrus sows with inflammatory secretions4 days after weaning),respectively.After serum isolation,enzyme-linked immunosorbnent assay(ELISA)was used to detect the levels of pro-inflammatory cytokines in sows.The results showed that serum concentrations of interleukin-1α(IL-1α),interleukin-1β(IL-1β),interleukin-6(IL-6),interleukin-8(IL-8)in sows with endometritis was significantly higher than those of healthy sows(P<0.01).,but there is no significant difference in the level of tumor necrosis factor-α(TNF-α)between healthy sows and animals with endometritis(P>0.05).3.Illumina Nova Seq 6000 sequencing platform was used to conduct high-throughput sequencing of V3-V4 region of 16 SrDNA gene in vaginal mucus samples from 24 pigs in Xinzhou,Shanxi Province and 28 pigs in Miyun,Beijing,respectively,and bioinformatics analysis was conducted to compare the differences of vaginal microflora between healthy animals and sows with clinical endometritis.The results showed that at the phylum classification level,in the sows with endometritis(E,n=12)and healthy group(C,n=12)in Xinzhou,Shanxi farms,and postnatal healthy group(P＿C,n=7),postnatal metritis group(P＿E,n=7)and postweaning healthy group(W＿C,n=7)and postweaning metritis group(W＿E,n=7),the major vaginal dominant bacteria were Firmicutes,Proteobacteria,Bacteroidetes,Fusobacteriota,Actinobacteria and Campylobactero.In the farm from Xinzhou,Shanxi Province,the abundance of Firmicutes,actinomyces,Proteobacteria,Bacteroidetes,Clostridium and Campylobacter was 44.76%,11.74%,15.27%,16.26%,4.70%and 3.46% in healthy pigs,respectively,but 57.28%,20.43%,12.26%,6.96%,0.17% and0.88% in sows with endometritis,respectively.In the farm from Beijing Miyun,the abundance distribution of Firmicutes,Proteobacteria,Bacteroidetes,Clostridium,actinomyces and Campylobacter in P＿C group was 44.94%,8.37%,24.93%,14.99%,3.60%and 2.15%,respectively,and 16.66%,47.94%,14.26%,14.77%,5.60% and 0.57% in P＿E group,and 7.91%,16.71%,17.88%,10.71%,3.24% and 2.53% in W＿C group,respectively,and 77.75%,3.82%,11.06%,0.11%,3.35% and 0.21% in W＿E group,respectively.At the level of genus classification,the comparison of vaginal dominant bacteria between C and E groups in the farm from Xinzhou,Shanxi Province showed that Corynebacterium Pasteurellaceae unclassified,Porphyromonas,Fusobacterium,and B acteroides in C group were higher than E group.But Trueperella,Streptococcus,Escherichia-Shigella,Clostridium sensu stricto 1 and Terrisporter was higher in E group than those of group C.The composition and abundance of vaginal bacteria in sows from Miyun,Beijing farm were different in four groups of vaginal domin ant bacteria.The top five bacteria genera were Fusobacterium(14.91%),Porphyrom onas(9.87%),Bacteroides(9.84%)and Parvimonas(6.13%)and Veillonella(5.67%) in P＿C group;and Escherichia-Shigella(33.40%),Fusobacterium(14.77%),Proteu s(12.62%),Porphyromonas(9.17%)and Bacteroides(4.22%)in P＿E group;and Fusobacterium(10.70%),Porphyromonas(9.23%),Veillonella(9.00%)and Streptoco ccus(6.68%),Pasteurellaceae＿unclassified(5.09%)in the W＿C group;and Clostri dium sensu stricto 1(7.76%),Terrisporter(5.26%),UCG-005(4.31%),UCG-002(3.90%),Christensenellaceae＿R-7＿group(3.28%)in the W＿E group.In conclusion,in a pig farm from Beijing Miyun,the incidence of endometritis was not related to parity,but related to abnormal delivery status.Weaning estrus rate and mating success rate of sows with endometritis were lower than those of healthy sows.The serum levels of IL-1α,IL-1β,IL-6 and IL-8 in sows with endometritis were up-regulated,suggesting that these factors may be used as markers of endometritis in sows.The composition and distribution of vaginal mucous microflora of sows with endometritis and healthy sows at different periods from Xinzhou and Beijing Miyun farms were different and complex at phylum and genus levels.