Effect of rice bran fermented with Ligilactobacillus equi on in vitro fermentation profile and microbial population

This study was conducted to assess the effects of fermented rice bran (FRB) with Ligilactobacillus equi on ruminal fermentation using an in vitro system. Oat hay, corn starch, and wheat bran were used as substrate for control. Ten percent of wheat bran was replaced with rice bran (RB), rice bran fermented with distilled water, and rice bran fermented with L. equi for T₁, T₂, and T₃, respectively. The experimental diets were mixed with buffered rumen fluid from wethers under nitrogen gas and incubated for 24 h at 39°C. The fermentation profile and microbial population were analyzed after the incubations. The results revealed that the RB and FRB (with or without L. equi) significantly reduced the gas, methane (CH₄), and CH₄ per dry matter digested (p < 0.001). Total short-chain fatty acid was also reduced in T₁ and T₂ in comparison with the control (p < 0.001). Propionate proportion was increased while butyrate proportion was reduced in response to treatment addition in cultures (p < 0.001). Anaerobic fungi and Fibrobacter succinogenes abundance were decreased in treatments (p < 0.001). Overall, CH₄ production in vitro can be reduced by RB and FRB supplementation as a result of the reduction of fiber-degrading microorganisms and a decrease in gas production.