The effects of supplemental nitrate administered alone or with a denitrifying ruminal bacterium, designated Paenibacillus 79R4 (79R4) intentionally selected for enhanced nitrate- and nitrite-metabolizing ability, on select rumen fermentation characteristics was examined in vivo. Rumen and blood samples were collected from cannulated Holstein steers one day prior to and one day after initiation of treatments applied as three consecutive intra-ruminal administrations of nitrate, to achieve the equivalent of 83 mg sodium nitrate/kg body weight day, given alone or with the nitrite-selected 79R4 (provided to achieve 10⁶ cells/mL rumen fluid). Results revealed a day effect on methane-producing activity, with rates of methane production by ruminal microbes being more rapid when collected one day before than one day after initiation of treatments. Nitrate-metabolizing activity of the rumen microbes was unaffected by day, treatment or their interaction. A day by treatment interaction was observed on nitrite-metabolizing activity, with rates of nitrite metabolism by rumen microbes being most rapid in populations collected one day after initiation of treatment from steers treated with nitrate plus 79R4. A day by treatment interaction was also observed on plasma methemoglobin concentrations, with concentrations being lower from steers one day after initiation of treatments than from collected one day prior to treatment initiation and concentrations being lowest in steers treated with nitrate plus 79R4. A major effect of treatment was observed on accumulations of most prominent and branched chain volatile fatty acids produced and amounts of hexose fermented in the rumen of animals administered nitrate, with concentrations being decreased in steers administered nitrate alone when compared to steers treated with nitrate plus the 79R4. These results demonstrate that the nitrite-selected Paenibacillus 79R4 may help prevent nitrite toxicity in nitrate-treated ruminants while maintaining benefits of reduced methane emissions and preventing inhibition of fermentation efficiency by the microbial ecosystem.

体内研究了单独施用硝酸盐或与反硝化瘤胃细菌（称为Paenibacillus 79R4（79R4））一起施用的补充硝酸盐对精选瘤胃发酵特性的影响，这些盐被选择性地选择来增强硝酸盐和亚硝酸盐的代谢能力。在开始连续三天瘤胃内施用硝酸盐的治疗开始前一天和治疗后一天，从空心荷斯坦ste牛中收集瘤胃和血液样品，单独或通过单独或联合使用，可达到相当于每天83 mg硝酸钠/ kg体重的水平。亚硝酸盐选择的79R4（提供达到10 ⁶细胞/ mL瘤胃液）。结果显示一天对甲烷产生活性的影响，瘤胃微生物的甲烷产生速率在开始治疗前一天比开始治疗后一天更快。瘤胃微生物的硝酸盐代谢活性不受日数，处理或相互作用的影响。每天观察到一种处理相互作用对亚硝酸盐代谢活性的影响，在处理开始一天后从用硝酸盐加79R4处理的公牛中收集的种群中，瘤胃微生物的亚硝酸盐代谢速率最快。每天也观察到血浆高铁血红蛋白浓度引起的治疗相互作用，处理开始后一天的ste牛皮中的浓度低于处理开始前一天的ste牛皮中的浓度，并且用硝酸盐加79R4处理的ste牛皮中的浓度最低。观察到治疗的主要效果是，施用硝酸盐的动物的瘤胃中产生的最显着和支链挥发性脂肪酸的积累和发酵瘤胃中己糖的发酵量，与用硝酸盐加硝酸盐处理的牛ers相比，单独施用硝酸盐的ste牛的浓度降低。 79R4。这些结果表明，亚硝酸盐选择 与使用硝酸盐加79R4处理的ers牛相比，仅使用硝酸盐的ste牛的浓度降低。这些结果表明，亚硝酸盐选择 与使用硝酸盐加79R4处理的ers牛相比，仅使用硝酸盐的ste牛的浓度降低。这些结果表明，亚硝酸盐选择芽孢杆菌79R4可以帮助防止经过硝酸盐处理的反刍动物中亚硝酸盐的毒性，同时保持减少甲烷排放的益处，并防止微生物生态系统抑制发酵效率。