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

Area of Science:

• Ruminant nutrition and environmental science
• Agricultural science and animal husbandry
• Microbiology and biochemistry

Background:

• Livestock production is a major contributor to climate change, with enteric fermentation in ruminants producing significant methane (CH4).
• Developing strategies to mitigate methane emissions from ruminants is crucial for environmental sustainability.
• Combining methane-mitigating agents presents a potential strategy to reduce environmental impact.

Purpose of the Study:

• To evaluate the effects of rice bran (RB) alone or combined with acrylate (AA) or pyruvate (PA) on in vitro rumen fermentation.
• To assess the impact of these treatments on methane (CH4) production and microbial populations.
• To determine the viability of RB and AA combination as a CH4 inhibitor.

Main Methods:

• In vitro evaluation of rumen fermentation parameters.
• Measurement of gas production, dry matter digestibility (DMD), and organic acid profiles.
• Analysis of microbial populations, including methanogens, anaerobic fungi, and specific bacterial species.

Main Results:

• The combination of rice bran and acrylate (AA) significantly reduced methane (CH4) production by over 66% and CH4/digested dry matter by 63%.
• AA treatment resulted in lower dry matter digestibility (DMD) and gas production compared to control and pyruvate treatments.
• AA cultures showed increased lactate and decreased acetate, propionate, and butyrate, with a significant reduction in methanogen populations.

Conclusions:

• Incorporating rice bran with acrylate shows potential as a viable methane (CH4) inhibitor in ruminant production.
• Further research is needed to determine the optimal inclusion level of rice bran and acrylate due to observed negative effects on gas production and DMD.
• The study highlights the complex interactions between feed additives, rumen fermentation, and microbial communities in mitigating methane emissions.