Sodium Humate And Glutamine Combined Supplementation Alleviate Diarrhea of Weaned Calves Via Alter Intestinal Microbiota And Metabolites

Abstract Background: Weaning is one of the most stressful periods that cause gastrointestinal tract dysfunction and diarrhea in calves. HNa and Gln were reported to exert beneficial effects on promoting growth performance, decreasing diarrhea incidence, and modulating intestinal microbiota in animals. Therefore, this study investigated the effect of HNa and Gln combined supplementation on growth performance, diarrhea incidence, serum parameters, intestinal microbiome, and metabolites of weaned calves.Results: In Exp. 1, 40 calves at 51±3 days of age with similar body weight (66.82±4.31 kg) were randomly assigned to 4 treatments fed with a basal diet (NC group), and a basal diet supplemented with 100 mL of 1%, 3%, or 5% HNa+1% Gln, twice daily, respectively. In a 21-day trial, calves on the 5% HNa+1% Gln group had higher ADG and lower fecal score and diarrhea incidence than those in the control group (P < 0.05). In Exp. 2, 20 calves at 51±3 days of age with similar body weight (69.37±6.28 kg) were randomly assigned to 2 treatments fed with a basal diet (NC group) and a basal diet supplemented with 100 mL of 5% HNa+1% Gln, twice daily (H+G group, the dose was obtained from Exp. 1). In a 21-day trial, calves supplemented with HNa and Gln had higher final BW and ADG, serum IgG concentration and GSH-Px and T-AOC activities, but lower fecal score, diarrhea incidence, as well as serum DAO, D-lac, TNF-α, and MDA concentrations compared to NC group (P < 0.05). Analysis of intestinal microbiota indicated that supplemented with HNa and Gln significantly increased the abundance of phyla Firmicutes and genus of Bifidobacterium, Lactobacillus, Olsenella, Ruminiclostridium 9, Howardella, and uncultured organism, whereas the abundance of phyla Bacteroidetes, genus of Helicobacter and Lachnoclostridium were decreased as compared with NC group. Moreover, untargeted metabolomics analysis revealed that supplemented with HNa and Gln altered 18 metabolites and enriched 6 KEGG pathways (primary fatty acid biosynthesis) compared to the NC group. Conclusions: This study showed that combined supplemented with HNa and Gln could decrease diarrhea of weaned calves, which may be associated with improved intestinal microbial ecology and altered metabolism profile.