| Failure of passive immune transfer in calves is hazardous to health,with no well-known effective recovery measures in practice.Four experiments were conducted in this study to explore the effects of using fecal microbiota transplantation(FMT)on the growth,health,blood cells,blood biochemistry,intestinal barrier function,and intestinal microflora of calves with failure of transfer of passive immunity.The experiment was conducted as a randomized complete block design with Holstein male calves.The calves were blocked by body weight and date of birth into 10 blocks of 3 calves each(30 calves in total).Calves within each block were randomly assigned to 3 treatments:calves fed 4 L of colostrum within 1 h after birth(PC),or 4 L of milk replacer within 1 h after birth(NC),or NC calves treated with fecal microbiota on d 4 and d 6(TN).The effect of FMT on the growth and health status of calves with failure of passive immune transfer was investigated in the first trial.The body weight of calves was recorded on d 0,5 and 9,and the rectal temperature of calves and the moisture content of feces were determined daily.Twenty-four calves(8 blocks)were randomly selected on d 9,slaughtered and the weight of the organs and carcass measured.During the experimental period,the average daily gain of calves in PC and TN was higher than that of NC(P<0.01).Calves in TN had higher body temperature than NC(P<0.05),while PC had the lowest(P<0.01).The fecal moisture content of PC was lower than NC(P<0.05),and no differences was detected between TN and PC.Moreover,PC had higher carcass weight than NC(P<0.05).The heart index of NC was greater than that of PC and TN(P<0.05),while PC had a lower liver and kidney index compared to TN and NC(P<0.01).The hematological profile and blood biochemical composition of calves were studied in the second trial.The blood samples used for hematological profile test were collected on d 1,5 and 9.The samples used for biochemical analysis were collected on d 1,3,5,7 and 9 before morning feeding.During the post-FMT period,the concentration of plasma haptoglobin was lower(P<0.01),while the serum NO content was higher(P<0.05)for PC when compared to NC.On the other hand,NC had higher plasma diamine oxidase than PC and TN(P<0.01),while no differences were observed between PC and TN.In addition,the mean red blood cell hemoglobin content and concentration,platelet numbers,mean platelet volume,and platelet pressure were higher(P<0.05)in NC compared to PC and TN.No differences were observed between TN and PC.The intestinal microbiota structure was assessed in the third trial.Eighteen calves(6 blocks)were randomly selected and slaughtered on the d 9 of age,and the digesta and mucosa samples of jejunum,ileum,cecum and colon were collected for microbiota analysis using 16S rDNA high-throughput sequencing.In total,4 genera in digesta and 17 genera in mucosa of jejunum and ileum,and 1 genus in digesta and 4 genera in mucosa of cecum and colon in calves with failure of passive immune transfer were affected by FMT.The relative abundance of Staphylococcus in jejunum mucosa was higher(P<0.05),Veillonella and Enterococcus in ileal digesta were lower(P<0.05),Escherichia-Shigella in cecum mucosa was lower(P<0.05)and Lactobacillus in cecum mucosa was higher(P<0.05)in PC compared to NC.There were no statistical differences detected between PC and TN.Additionally,calves in TN had higher(P<0.05)relative abundance of Peptostreptococcus in colonic digesta,while NC had higher(P<0.05)Campylobacter in colonic mucosa than the other groups.The fourth trial determined the effect of FMT on tight junctions in the intestinal epithelium of calves.Twenty-four calves(8 blocks)were randomly selected and harvested on d 9 of age.The mucosal samples of jejunum,ileum and colon were collected to study the expression of genes related to intestinal barrier function.The tissue samples of jejunum and colon were collected for immunohistochemical analysis.Calves in TN had higher(P<0.05)claudin-4 and occludin gene expression in colon compared with PC.The relative expression of IL-8 gene in all the intestinal mucosa detected was upregulated(P<0.05)in PC compared to NC,and no differences were observed between PC and TN.The PC and TN calves had higher(P<0.05)IL-10 gene expression in jejunum than NC,but no difference between themselves.The protein expression of claudin-1 in jejunum,and occludin in jejunum and colon were higher for TN compared to PC(P<0.01).Calves in PC had higher(P<0.05)ZO-1 protein expression than NC,but was similar to TN.Moreover,PC calves had higher(P<0.05)sIgA protein expression in colon than TN and NC,and the calprotectin protein expression in jejunum was the highest in NC,followed by TN,and lastly PC was the lowest(P<0.01).In conclusion,the intestinal microbial structure and the barrier function of calves with failure of passive immune transfer were improved,concurrently,the growth and health status of these calves was positively affected by FMT.Hence,FMT could be promoted and applied in practice as an effective rescue preventive measures for failure of passive immune transfer in calves. |
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