Effects Of Compound Probiotics On Improving Health And Gut Microbiota Of Canine Of Different Ages

Probiotics could promote human and animal health and have many beneficial effects on the host,such as inhibition of the colonization of pathogenic microbes,regulation of host immunity and metabolism,and improvement of intestinal barrier function.However,only limited studies have focused on using probiotics to improve the health of hosts with different age.Canine is a good animal model for human gut microbiome research because of the high similarity between dog and human microbiomes.Thus,dog studies provide a double benefit:for dogs directly and for the potential to generalize to humans.To investigate the effects of probiotics on different age canine,the changes in basal physiological parameters,feed intake,body weight gain and immunity of 90 dogs at day 0,30,60 of probiotics administration and 15 days after ceasing probiotic treatment were monitored.Meanwhile,the gut microbial composition and structure of different age dogs were analyzed based on PacBio SMRT sequencing,further,the effects of probiotics on different age dogs were explored.Additionally,the beneficial effects of probiotics in improving the composition and function of the gut microbiota in dogs with diarrhoea were revealed by metagenomic sequencing.The results demonstrated:(1)The diversity in canine gut microbiota is much enriched.The most dominant and core bacteria belong to Firmicutes,Bacteroidetes,Fusobacteria,Proteobacteria and Actinobacteria,including Clostridium,Alloprevotella,Bacteroides,Fusobacterium,Prevotella,Ruminococcus,Eubacterium.The significant difference in composition and structure of intestinal microbiota were observed in different age dogs.(2)The probiotics significantly promoted the feed intake of the elderly dogs and the weight gain of all dogs,descreased the proportion of diarrhoea in dogs,enhanced the level of serum IgG(P<0.001),IFN-a(P<0.05),and fecal SIgA(P<0.001),while reduced the TNF-a(P<0.05).(3)The probiotics obviously changed the gut microbial structure of elderly dogs and significantly increased beneficial bacteria(such as Faecalibacterium prausnitzii)and decreased potentially harmful bacteria(such as Sutterella stercoricanisin),and the elderly dogs showed the strongest response to the probiotics.(4)The relative abundance of increased bacteria after probiotics administration,such as Faecalibacterium prausnitzii,were positively correlated with the levels of fecal SIgA,serum IgG and body weight,feed intake,as well as negatively correlated with TNF-α、IL-6;in constrat,the decreased bacteria,such as Sutterella and Blautia,were was positively associated with TNF-α、IL-6,and negatively linked to SIgA,IgG and body weight,feed intake,suggesting that the probiotics improved the host health through regulating canine gut microbiota.(5)The gut microbiota of the elderly dogs shifted towards a younger-like composition at day 60 of probiotics treatment based on the Random Forests.(6)On the basis of metagenomic analysis,probiotic administration was accompanied by changes in the gut microbiota composition,interactions between the gut microbes,as well as upregulated the pathways of Amino acid metabolism,Metabolism of cofactors and vitamins,Biosynthesis of other secondary metabolites and Replication and repair,and downregulated cell motility and cellular processes and signaling of gut microbiome,which might relate to the improvement of diarrhoea in dogs.The present study analyzed the composition and structure of intestinal microbiota in dogs and further explored the influence of probiotics on the health status and intestinal microbiota in different age dogs.Our results suggested the probiotic treatment effects were age-related and provided interesting insights into future development of personalized probiotic-based strategies to improve human and animal health.