A low-cost continuous rumen simulation system for sustainable in vitro fermentation and feed evaluation in ruminant production

In vitro simulation of rumen fermentation is critical for improving feed efficiency, assessing dietary interventions, and supporting methane mitigation strategies in ruminant production systems. However, existing fermentation platforms are often expensive, technically complex, or poorly suited for long-term microbial viability under near-rumen conditions-especially in resource-limited settings. This study presents the development and validation of a modular, low-cost <b>Continuous Rumen Bioreactor (CRB)</b> engineered to replicate key physiological parameters of the rumen, including temperature control (39-40 °C), continuous buffering via artificial saliva infusion, anaerobic regulation, and simulated motility through mixing pumps. A novel feed cartridge system was incorporated to facilitate uninterrupted substrate exchange during multi-week incubations. The system was tested using rumen liquor from buffalo calves and evaluated for fermentation consistency, pH stability, gas production, and dry matter degradation. Results demonstrated that the CRB maintained functional microbial activity over extended durations, providing reliable and reproducible fermentation outcomes. The system offers a scalable and accessible alternative to conventional in vitro models and supports practical applications in feed evaluation, microbial enrichment, and enteric methane mitigation strategies. Its affordability and adaptability make it particularly relevant for use in developing countries and decentralized agricultural research systems.•A low-cost, modular Continuous Rumen Bioreactor (CRB) was developed to simulate rumen fermentation over extended durations.•Maintains key rumen conditions (temperature, pH, anaerobiosis, and motility) and supports consistent microbial activity.•Suitable for feed evaluation, microbial enrichment, and methane mitigation research, especially in resource-limited settings.