硝酸盐对肉牛甲烷产量和生长性能的影响
Effect of nitrate on the methane production and productivity of cattle

为研究硝酸盐对肉牛甲烷排放，瘤胃发酵和生长性能的影响，采用体内和体外试验。体外试验用单因素设计，分为对照组，1%硝酸盐组和2%硝酸盐组，试验重复进行3次；在体内试验中，选用8头草原红牛，采用单因素随机分组设计，分为对照组（体重（229.5±50.1） kg）和硝酸盐组（（体重232.3±37.7） kg），每组4头。试验共56 d，包括14 d预饲期，39 d生长期以及3 d呼吸测热期。结果表明：在体外试验中，在1%和2%硝酸盐下甲烷量分别下降15.2%和46.2%，在体内试验中1%的硝酸盐可以抑制28.5%的甲烷产量，且饲喂后4 h内抑制效果显著（P<0.05），甲烷产量与干物质采食量之比以及甲烷能与总能比表示时分别下降31.8%，且对总挥发性脂肪酸产量有显著抑制效果（P<0.05），但日增重、饲料转化率和营养消化率并未增加。硝酸盐可以持续有效地抑制甲烷，但未对生产性能产生促进作用。
Aiming to study the effect of nitrate on methane yield,rumen fermentation and growth of cattle,in vitro and in vivo experiments were conducted.In vitro experiment was designed by single factor including control,1% and 2% nitrate with 3 replicons.In vivo experiment was conducted on 8 cattle,which was single factor randomized design including no additives and 1% nitrate.The experiment was continued for 56 days,which was 14 d of dietary adaption period,39 d of ad-libitum feeding growth and 3 d of 80% limited feed in chambers.The results showed that the methane productions were respectively decreased by 15.2% and 46.2% under the administrations of 1% and 2% nitrate in in vitro experiment.The methane production was declined by 28.5% in 1% nitrate at 4 h after feeding in in vivo.The reduction of methane/DMI and methane energy/gross energy was respectively 31.8%.Although there were no differences in daily weight gain and feed conversion ratio were not different between treatments and control,nitrate significantly inhibited VFA production.In conclusion,nitrate effectively restrained methane,while had no positive impact on production performance.