Grape seed proanthocyanidin improves intestinal inflammation in canine through regulating gut microbiota and bile...

Although certain progress has been made in treating canine inflammatory bowel disease (IBD), a large proportion of dogs have a poor prognosis and may develop resistance and side effects. Therefore, it is of great significance to prevent or alleviate canine IBD through nutritional intervention. Plant polyphenol can interact with intestinal bacteria and has important prospects in the intestinal health improvement. This study evaluated the effect of grape seed proanthocyanidin (GSP), a plant-derived natural polyphenol, on Labrador Retrievers with mild IBD. In Experiment 1 of this study, GSP alleviated persistent intestinal inflammation in canines by improving inflammatory indexes and reducing intestinal permeability. Moreover, GSP treatment increased the abundance of bacteria with potential anti-inflammatory properties and engaging bile acid metabolism, including Ruminococcaceae, Faecalibacterium, Ruminococcus_torques_group, and Lachnospiraceae_NK4A136_group. Notably, targeted metabolomic analysis identified elevated productions of fecal chenodeoxycholic acid and its microbial transformation product lithocholic acid, which might contribute to relieving canine intestinal inflammation. Further, in Experiment 2, fecal microbiota transplantation was used to determine whether gut microbiota is a potential mechanism for GSP efficacy. Dogs with mild IBD received the fecal microbiota from the group administered GSP and mirrored the improvement effects of GSP, which results verified that gut microbial alteration could be an underlying mechanism for GSP efficiency on canine IBD. Our findings highlight that the mechanism of the GSP function on canine IBD is mediated by altering gut microbial composition and improving bile acid metabolism. This study proposes a natural polyphenol-based dietary strategy for improving canine intestinal health.