Pueraria lobate polysaccharides alleviate neonatal calf diarrhea by modulating gut microbiota and metabolites

Abstract

Background Neonatal calf diarrhea (NCD) is still one of the most critical diseases in calf rearing. Studies have shown that Pueraria lobata polysaccharides (PLP) have intense antioxidant and immunomodulatory activity and modulate gut microbiota. This randomized clinical trial aimed to investigate the effect of PLP on fecal score, inflammatory cytokines, antioxidant activity, fecal microbiota and metabolites in diarrheic calves. Methods 12 neonatal calves (7–8 day ages and 45–55 kg weights) with fecal scores ≥ 2 were determined as diarrhea then orally administered PLP (400mg/kg BW) QD for five consecutive days. 12 age-matched healthy calves with a fecal score ≤ 1 were selected as the control group. Fecal samples and blood samples were collected from the rectum and tail of diarrheic calves (DS) and calves in the control group (HS) on the 0 d; then collected fecal samples and blood samples from diarrheic calves treated with PLP (TS) on the 7 d of the trial. Fecal or blood samples of these calves were analyzed in inflammatory cytokines, antioxidant activity, fecal microbiota and metabolites. Results Studies showed that treatment with PLP decreased the fecal score of diarrheal calves, serum concentrations of IL-1β, TNF-α, and malondialdehyde, and also elevated the level of superoxide dismutase. In addition, PLP treatment altered the gut microbiota, significantly increased the relative abundances of beneficial bacteria, including the phyla Bacteroidetes and Actinobacteria, the genus Collinsella, Megamonas and Bifidobacterium; decreased the relative abundances of pathogenetic or diarrhea related bacteria, such as Proteobacteria, Fusobacteria, Clostridium_sensu_stricto_1, and Escherichia_Shigella. Moreover, PLP can increase the fecal concentrations of isobutyric acid, propionic acid, and pantothenate; lower the levels of PC (18:0/18:1(9Z)), arachidonic acid, and docosahexaenoic acid. Conclusions PLP perform the therapeutic activity via alleviating intestinal inflammation and regulating gut microbiota, avoiding further dysbiosis to restore the metabolism of gut microbiota, and finally promoting the recovery of diarrhea. The change further mitigated intestinal inflammation and oxidative damage in diarrheal calves.