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.

Effect of rice bran extract on in vitro rumen fermentation and methane production.

This study was done to investigate which components of rice bran (RB) are involved in the inhibition of methanogenesis by fractionating the rice bran and adding it to a rumen in vitro culture system. The RB extract obtained using ethanol and water was screened in an in vitro fermentation system. The experimental treatment conditions were as follows: a control group containing a substrate without supplements; substrates with 0.06 g of RB; 0.6 mL of ethanol; 0.6 mL of distilled water (DW); 0.6 mL of ethanol-soluble fraction (ESF); 0.06 g of ethanol-insoluble rice bran (EIRB); 0.6 mL of water-soluble fraction (WSF); and 0.06 g of water-insoluble rice bran (WIRB). Based on the result of the analysis, the addition of ESF significantly decreased CH4 and CH4 /g dry matter digested, methanogen population (p < 0.05), while gas and dry matter digestibility (DMD) were comparable with the control group. Total short-chain fatty acid (SCFA), and proportion of propionate were reduced, and the proportion of butyrate was increased by the addition of ethanol and ESF (p < 0.05). This result suggests that the supplementation of 10% ESF can substantially reduce methane production in vitro without a negative effect on substrate digestibility.

Nutritional quality and organic acid profile of rice bran fermented with lactic acid bacteria isolated from horse feces.

The study aimed to determine the effect of Limosilactobacillus equigenerosi and Ligilactobacillus equi as inoculants for solid-state fermentation (SSF) in the proximate composition of nutrients and organic acid profile of rice bran (RB). The RB was treated with distilled water (DW) without inoculant (control), L. equigenerosi (T1 ), L. equi (T2 ), and L. equigenerosi and L. equi 1:1 (v:v) (T3 ). For the treatments, 90 mL of culture was pelleted and suspended with DW. Each treatment was replicated three times and incubated for 4, 7, and 10 days at 37°C. The crude protein, ether extract, crude ash, crude fiber, neutral detergent fiber, and acid detergent fiber were increased (P < 0.05) in fermented RB. The lactate and total organic acid produced were increased by the addition of lactic acid bacteria (LAB) (P < 0.01), and the highest concentrations were recorded in treatments containing L. equi (T2 and T3 ). Acetate production in T1 was highest than in control, T2 , and T3 (P < 0.01). The results showed that LAB isolated from horse feces in combination with SSF can improve the quality of RB as an ingredient for animal feed based on the higher concentrations of protein, carbohydrates, minerals, and organic acids.