Exploration Of Pathogenicity Of Peafowl-derived Coccidia On Chickens And Its Influence On The Diversity Of Peafowl Intestinal Flora

Coccidia is a class of globally distributed parasites that cause coccidiosis in livestock,poultry,wild animals and even humans.In peafowl as a Yunnan locally characteristic species,coccidiosis is a common intestinal parasitic disease.At present,most reports on peafowl-derived coccidia in Yunnan Province focus on epidemiological investigation and case diagnosis and treatment,while the pathogenicity of coccidia in Phasianidae such as chicken and the effect of coccidia on the intestinal microflora of peafowl remains unclear.Therefore,in this paper,a study covering the following three aspects was conducted.First,the identification of peafowl-derived coccidia species:In this study,fecal and anal swab samples were collected from peafowl in a Kunming Zoo and microscopic examination was performed.As a result,serious Eimeria infection was found with obvious dynamic changes with seasons and a peak in summer up to a density of 3200.Combination of PCR amplification of the ITSs and the ITSs gene of Eimeria and the phylogenetic analysis revealed that the pathogens belong to Eimeria pavonis and Eimeria meleagrimitis.Concurrent infection caused by two or three Eimeria species also existed,which suggested possible cross-infection between peafowl and chicken.Second,the pathogenic study of peafowl-derived Eimeria spp.in chickens:In this study,14-day-old chicks were inoculated with sporulated oocysts of peafowl-derived Eimeria spp.via crop at a dose of 3×10~4,while the control group were administrated with equal volume sterile saline.Preliminary understanding of the pathogenicity of peafowl-derived Eimeria spp.to chickens by observing the clinical pathological changes of mental outlook,weight,appetite,water drinking,feces,histopathological changes and PCR examination of the amount of Eimeria ITSs genes.Compared with the control group,the experimental group had rheumy feces and became weaker with fluffy feathers,while the indexes of weight and appetite appeared no significant changes.No oocyst was detected in the experimental group.Compared with the control group,the experimental chicks had slight bloat in intestinal tract,a small amount of mucoid exudate in the intestinal cavity,and needle-like hemorrhagic spots were found in the intestinal epithelium.The pathological sections found that the lamina propria of the cecum of the experimental group had a large amount of lymphocyte infiltration compared with the control group,accompanied by a small amount of hemorrhage and cell necrosis.The target fragment was not amplified by using PCR.The results show that the intake of peafowl earmus can cause damage to intestinal epithelial cells,and the relevant pathogenic mechanism needs further study.Third,the effect of peafowl-derived Eimeria spp.infection on the intestina l microflora of peafowl:A total of 6 anal swab samples from the infected and control groups were analyzed for the diversity of peafowl gut flora using 16S r RNA high-throughput sequencing.The results showed that Proteobacteria,Fir micthe,Bacteroidotes and Actinobacteriota were the predominant bacterial phyla in all samples.Compared with the control group,the relative abundance of th e phylum Proteobacteria and Actinobacteriota increased substantially and the rel ative abundance of the phylum Firmicutes and others decreased significantly(P<0.05)in the Eimeria-infected group.At the genus level,Escherichia-Shigella,Christensenellaceae-R-7-group,Treponema,and Corynebacterium were the main genera in all samples.Compared with the control group,the relative abundanc e of Escherella-Shigella,Corynebacterium,Lactobacillus,etc.increased,while t he relative abundance of prevotellaceae＿UCG-001,Ruminococcus,norank-f-Euba cterium-coprostanoligenes-group and Bacteroides,etc.reduced in the infected gr oup.This study revealed serious infection of Eimeria spp.in peafowl that required specific drug administration for effective control on the transmission and dispersal of the pathogen.The results from the experiment of pathogenicity of peafowl-derived Eimeria spp.to other pheasant species suggested that the prevention and control of coccidiosis should be strengthened.This study comprehensively addressed the effect of Eimeria spp.infection on the intestinal microflora in peafowl,providing supportive data for the subsequent development of microbial modulators to prevent and treat peafowl coccidiosis and of measures related to veterinary public health.