摘要：Background and Objective:This study aimed to examine the effect of sodium nitrate inclusion in a total mixed ration based on tofu waste on in vitro methane production. Ruminant methane production reflects livestock feed energy loss, indicating low feed energy utilization. Thus, a reduction in ruminal methane production is required to improve feed utilization and livestock productivity. Materials and Methods:The total mixed ration based on tofu waste was treated with the addition of sodium nitrate at levels of 0.0, 1.0, 2.5, 5.0, 7.5 and 10.0 mM. The ruminal gas production of each sample was observed in vitro for 48 h at 39°C. Three replicates of the samples were used. At the end of incubation, microbial protein synthesis, the volatile fatty acid (VFA) concentration and methane production were determined. The data were analysed statistically by using one-way ANOVA. Results:The addition of up to 10.0 mM sodium nitrate did not affect pH, total gas production, CGA, ammonia, rumen microbial synthesis and the protozoa population (p<0.05). Nevertheless, the addition of sodium nitrate tended to reduce methane production (p = 0.057). Conclusion:The addition of up to 10 mM sodium nitrate in a total mixed ration based on tofu waste did not affect the nature of microbial fermentation in the rumen but tended to reduce methane production.
