This study aimed to evaluate the effects of the administration of sodium humate (NaH) on the growth performance, diarrhea incidence, and fecal microflora of pre-weaned Holstein calves. In a 53-day experiment, forty healthy newborn female calves were randomly allocated to the following four treatment groups: (1) control (basal diet); (2) 1-gram NaH (basal diet extra orally supplemented with 1 g of NaH dissolved in 100 mL of milk or milk replacer daily); (3) 3-gram NaH (basal diet extra orally supplemented with 3 g of NaH dissolved in 100 mL of milk or milk replacer daily); and (4) 5-gram NaH (basal diet extra orally supplemented with 5 g of NaH dissolved in 100 mL of milk or milk replacer daily). NaH was mixed with milk (d 2–20) or milk replacer (d 21–53). Calves in the 5-gram NaH group had a higher ADG during d 1 to 21 and d 21 to 53 than the other groups did (p < 0.05). Fecal scores and diarrheal incidence were significantly lower in the 3-gram and 5-gram NaH groups than the 1-gram NaH and control groups during d 1 to 20 (p < 0.05). The serum IgA, IgG and IL-4 concentrations, and T-SOD and T-AOC activities were higher, and the serum IL-6, TNF-α, D-lactic acid, and MDA concentrations were lower in the 5-gram NaH group than the control group (p < 0.05). Furthermore, NaH supplementation increased the abundances of Bifidobacterium and Lactobacillus but decreased the abundance of Escherichia coli in feces (p < 0.05). These encouraging findings indicated that supplementation with 5 g of NaH effectively improved the immune status, antioxidant capacity, and intestinal beneficial bacteria, and further improved the growth performance and reduced the diarrhea incidence of the pre-weaned dairy calves.

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.

This study aimed to evaluate the effects of administration of sodium humate (HNa) and glutamine (Gln) on growth performance, diarrhoea incidence, serum parameters, and faecal microflora of pre-weaned Holstein calves. In a 57-day experiment, 28 healthy newborn female calves were randomly allocated to four treatment groups: (1) CON (control); (2) HNa (basal diet + 5% HNa); (3) Gln (basal diet + 1% Gln); and (4) HNa + Gln (basal diet + 5% HNa + 1% Gln). The calves in the CON group were fed with basal diet.HNa and Gln were alone or together mixed with milk (Days 1-20) or milk replacer (Days 21-57) and orally administered to each calf. The results indicated that calves combined supplemented with HNa and Gln had a higher average daily gain at 0-21 days, 21-57 days, and 0-57 days, and starter intake at 21-57 days and 0-57 days (p < 0.05).Compared with the CON group, calves in HNa, Gln, and HNa + Gln groups showed lower faecal scores and diarrhoea incidence at 0-21 days and 0-57 days (p < 0.05). Combined administration of HNa and Gln increased the concentration of IgG and IgA, activities of glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) but decreased the concentration of diamine oxidase (DAO), D-lactic acid (D-lac), TNF-α, and malondialdehyde (MDA) in the serum of calves compared with the CON group throughout the entire period (p < 0.05). Furthermore, the abundances of Bifidobacterium and Lactobacillus were increased but the Escherichia coli was decreased in faecal grab samples of HNa + Gln group calves in comparison with the CON group (p < 0.05). In conclusion, combined administration of HNa and Gln effectively improved the growth performance, antioxidant and immune status, and intestinal beneficial bacteria, and further reduced the diarrhoea incidence of the pre-weaned calves.