复合益生菌对艾美耳球虫感染断奶羔羊生产性能、免疫功能和肠道菌群的影响OA

This study aimed to investigate the effects of compound probiotics on growth performance,immune function,intestinal microbiota,and fecal oocyst shedding in weaned lambs experimentally infected with Eimeria.Forty 50-day-old weaned Hu lambs with similar body weight and health status were randomly assigned to four groups:Control(CON)group,Eimeria-infected(CI)group,Compound probiotics(CP)group,and Diclazuril-treated(DT)group.Initial body weight,final body weight,and feed intake were recorded to calculate average daily gain(ADG),average daily feed intake(ADFI),and feed conversion ratio(FCR).At the end of the 35-day trial,blood samples were collected to measure serum biochemical parameters and immune-related indices.Immune organs,including the liver and thymus,were weighed to calculate organ indices.During the experiment,fecal scores were recorded periodically to assess diarrhea,and oocysts per gram of feces(OPG)were counted.Rectal contents were collected,and microbial community structure was analyzed using Illumina MiSeq high-throughput sequencing.The results showed that the coccidial infection model was successfully established.Compared with the CI group,lambs in the CP group showed significantly increased ADG and ADFI(P<0.01).Serum total protein(TP),albumin(ALB),interleukin-2(IL-2),and the numbers of CD4⁺and CD8+T lymphocytes were significantly increased(P<0.05 or P<0.01),while creatinine(CREA)levels were significantly decreased(P<0.05).In addition,dietary supplementation with compound probiotics reversed the increases in liver weight and liver index as well as the decrease in thymus weight caused by Eimeria infection(P<0.05),significantly alleviated diarrhea(P<0.05),and reduced oocyst shedding.Regarding intestinal microbiota,the Chao1 and Shannon indices were significantly increased(P<0.01),indicating improved microbial richness and diversity,and the microbial community structure was optimized.These results suggest that compound probiotics can alleviate growth inhibition and diarrhea caused by coccidial infection in lambs by enhancing immune function,increasing microbial abundance,and optimizing gut microbiota structure.Their effects are comparable to those of diclazuril,while avoiding potential side effects associated with chemical drugs.