Effect of sequestering agents based on a Saccharomyces cerevisiae fermentation product and clay on the ruminal bacterial community of lactating dairy cows challenged with dietary aflatoxin B1.

This study was conducted to examine the effects of clay (CL) and Saccharomyces cerevisiae fermentation product (SCFP) on the ruminal bacterial community of Holstein dairy cows challenged with aflatoxin B1 (AFB1). A second objective was to examine correlations between bacterial abundance and performance measures. Eight lactating dairy cows stratified by milk yield and parity were randomly assigned to 4 treatments in a 4 × 4 Latin square design with 2 replicate squares, four 33-d periods, and a 5-d washout between periods. The treatments included (1) control (basal diet, no additive); (2) T (control + 63.4 µg/kg AFB1, oral dose); (3) CL (T + 200 g/head per day of sodium bentonite clay, top-dress); and (4) CL+SCFP [CL + 19 g/head per day Diamond V NutriTek (Diamond V Inc., Cedar Rapids, IA) + 16 g/head per day MetaShield (Diamond V Inc.), top-dress]. Cows were adapted to diets containing no AFB1 from d 1 to 25 (predosing period). From d 26 to 30 (dosing period), AFB1 was orally dosed and then withdrawn for d 31 to 33 (withdrawal period). During the predosing period, compared with the control, feeding CL and CL+SCFP increased the relative abundance of the most dominant phylum, Bacteroidetes (55.1 and 55.8 vs. 50.6%, respectively), and feeding CL+SCFP increased Prevotella abundance (43.3 and 43.6 vs. 40.0%, respectively). During the dosing period, feeding AFB1 did not affect the ruminal bacterial community, but the relative abundance of Fibrobacteraceae increased with CL+SCFP compared with T (1.45 vs. 0.97%); Fibrobacter abundance also tended to increase with CL+SCFP compared with T and control, respectively (1.45 vs. 0.97 and 1.05%, respectively). Feeding AFB1 with or without CL or CL+SCFP did not affect ruminal pH or concentrations of NH3-N, total volatile fatty acids, or individual volatile fatty acids. Milk yield and milk component yields were positively correlated with the relative abundance of unclassified Succinivibrionaceae, unclassified YS2, or Coprococcus. Feed efficiency was positively correlated (r ≥ 0.30) with the relative abundance of unclassified YS2, Coprococcus, or Treponema. Feeding aflatoxin at 63 µg/kg, a common contamination level on farms, did not affect the abundance of dominant bacteria or rumen fermentation. When aflatoxin was fed, CL+SCFP increased the abundance of Fibrobacter, a major fibrolytic bacteria genus. Milk yield and DMI were positively correlated with abundance of Succinivibrionaceae and Coprococcus. Feed efficiency was positively correlated with abundance of Coprococcus, Treponema, and YS2. Future studies should speciate culture and determine the functions of the bacteria to elucidate their roles in the rumen and potential contribution to increasing the performance of dairy cows.

Butyrate promotes the recovering of intestinal wound healing through its positive effect on the tight junctions.

Postweaning diarrhea is one of the most common causes of morbidity and mortality in weanling piglets. Feeding sodium butyrate to weanling piglets decreased the incidence of diarrhea, but the mechanism has not been fully elucidated. The present study was to evaluate the effect of sodium butyrate on diarrhea in relation to wound healing of intestinal barrier using IPEC-J2 cell model. Cultured cells were scratched to induce wound and then were treated with 4 mM sodium butyrate. The results showed that supplementation of the cells with sodium butyrate significantly promoted the process of wound healing, indicating the protective effects of butyrate on the intestinal mucosa. Butyrate treatment enhanced mRNA expression of the intestinal mucosal tight junction proteins occludin and zonula occluden protein-1 (P < 0.05), which suggested that the promotion of wound healing by butyrate is related to the maintenance of the function of the intestinal barrier. In addition, in the butyrate-treated group, intestinal total superoxide dismutase and glutathione peroxidase (P < 0.05), two of the main antioxidant enzymes, as well as glutathione (P < 0.05), one of the nonenzymatic antioxidant components, were enhanced whereas the malondialdehyde level, a marker of free radical mediated lipid peroxidation injury, was decreased (P < 0.05) compared with the control group. Collectively, these results indicate that dietary sodium butyrate might, at least partly, play an important role in recovering the intestinal tight junctions having a positive effect on maintaining the gut integrity.