Abstract：
Postweaning diarrhea (PWD) is a multifactorial disease caused by different aetiological agents, like viruses or bacteria and where the role of the microbiota remains unclear. The aim of this study was to assess differences between healthy and diarrheic weaned pigs concerning the prevalence of pathogens and changes in the intestinal microbiota. Eighteen farms with PWD were selected and 277 fecal samples were collected (152 diarrheic vs 125 healthy). Presence of Rotavirus A (RVA), B (RVB), C (RVC) and Porcine Epidemic Diarrhea Virus (PEDV), virulence factors of Escherichia coli and Clostridioides difficile were analyzed by PCR. Finally, the microbiota composition was also study by 16 S rRNA sequencing on 148 samples (102 diarrheic vs 46 healthy). RVA (53.95 % vs 36 %, p=0.04) and RVB (49.67 % vs 28.8 %, p<0.001) were more frequent in diarrheic animals. Furthermore, RVA viral load was higher in diseased animals. VT2 toxin was significantly associated with diarrhea, whereas other virulence factors were not. Presence of C. difficile and PEDV was almost negligible. Regarding microbiota changes, Fusobacteriota phylum was more frequent in diarrheic samples and Ruminococcaceae family in healthy penmates. During the first week postweaning, Enterobacteriace and Campylobacteria were enriched in animals presenting diarrhea. Furthermore, Lactobacillus was detected in those individuals with no RVA infection. In conclusion, RVA seems to play a primary role in PWD. Classic E. coli virulence factors were not associated with diarrhea, indicating the need for revising their implication in disease. Moreover, Lactobacillus was found frequently in animals negative for RVA, suggesting some protective effect.
摘要：
断奶后腹泻（PWD）是由不同病因引起的多因素疾病，如病毒或细菌，微生物群的作用尚不清楚。这项研究的目的是评估健康和腹泻断奶猪在病原体流行和肠道微生物群变化方面的差异。选择了18个患有PWD的农场，并收集了277个粪便样本（腹泻152个，健康125个）。轮状病毒A（RVA）的存在，B(RVB),C（RVC）和猪流行性腹泻病毒（PEDV），通过PCR分析大肠杆菌和艰难梭菌的毒力因子。最后,还通过16SrRNA测序对148个样本(102个腹泻对46个健康样本)进行了微生物群组成研究.RVA（53.95%vs36%，p=0.04）和RVB（49.67%对28.8%，p<0.001)在腹泻动物中更常见。此外，患病动物的RVA病毒载量较高。VT2毒素与腹泻显著相关，而其他毒力因子则没有。艰难梭菌和PEDV的存在几乎可以忽略不计。关于微生物群的变化，在健康的青少年中，腹泻样品和反刍动物科的梭杆菌门更为常见。在断奶后的第一周，肠杆菌和弯曲杆菌在呈现腹泻的动物中富集。此外，在那些没有RVA感染的个体中检测到乳杆菌。总之,RVA似乎在PWD中起主要作用。经典大肠杆菌毒力因子与腹泻无关，表明需要修改它们在疾病中的含义。此外，在RVA阴性的动物中经常发现乳酸杆菌，表明有一定的保护作用.
