Assessment of rice bran with acrylate or pyruvate in modulating ruminal fermentation and methane production in vitro.

BACKGROUND

Livestock production contributes largely to climate change and methane (CH) from enteric fermentation is the primary greenhouse gas emitted from ruminants. Thus, developing effective strategies to reduce the impact of ruminant production on the environment is crucial, and the combination of CH mitigating agents may be a viable strategy to attain this. The present study aimed to evaluate the effect of rice bran alone (control+rice bran, RB) or in combination with acrylate (control+rice bran+acrylate, AA) or pyruvate (control+rice bran+pyruvate, PA) on rumen fermentation parameters, CH production, and microbial populations in vitro.

RESULTS

Gas production was highest in control + rice bran + pyruvate (PA) treatments and lowest (P < 0.01) in control + rice bran + acrylate (AA), whereas dry matter digestibility (DMD) was significantly lower (P < 0.05) in AA compared to control (CON) and PA. CH and CH/digested dry matter decreased (P < 0.05) by more than 66% and 63%, respectively, in AA cultures, whereas total organic acid production increased (P < 0.01) compared to CON. Lactate levels were significantly higher (P < 0.05), while acetate, propionate and butyrate were notably lower (P < 0.05) in AA cultures than CON. Microbial analysis showed a significant decrease in methanogen populations in AA than CON (P < 0.01). Compared to CON, anaerobic fungi and Megasphaera elsdenii populations declined across all treatments (P < 0.01), whereas Selenomonas ruminantium populations decreased in RB and AA, and Prevotella ruminicola populations were higher in RB and PA (P < 0.05).

CONCLUSION

These findings suggest that incorporating RB with AA could be a viable CH inhibitor; however, because of its negative effect on gas production and DMD, further investigations should be done to determine its optimum inclusion level. © 2025 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.