利用人工瘤胃产气法比较不同品种肉牛瘤胃发酵特性和产甲烷差异

Comparison of Rumen Fermentation Characteristics and Methane Production of Different Breeds of Beef Cattle by Artificial Rumen Gas Production Method

本试验旨在利用人工瘤胃产气法比较不同品种肉牛瘤胃发酵特性和产甲烷(CH_4)等温室气体的差异。选用健康无病、年龄相近(24月龄)的麦洼牦牛、中国荷斯坦奶公牛、犏牛(藏黄牛×麦洼牦牛)阉公牛各5头,相同舍饲环境下饲喂相同饲粮42 d后,采集各品种肉牛瘤胃液进行相同饲粮底物的体外发酵,比较分析体外发酵产气量、产气参数、发酵参数以及CH_4、氢气(H_2)、二氧化碳(CO_2)产量。结果表明:1)各组产气量随着发酵时间延长呈增加趋势。犏牛组慢速发酵部分产气量和潜在产气量显著高于中国荷斯坦奶公牛组和麦洼牦牛组(P<0.05),而中国荷斯坦奶公牛组和麦洼牦牛组快速发酵部分产气量和产气速率显著高于犏牛组(P<0.05)。2)中国荷斯坦奶公牛组发酵24和48 h乙酸/丙酸显著高于其余2组(P<0.05),麦洼牦牛组发酵48 h丙酸和总挥发性脂肪酸(TVFA)含量显著高于其余2组(P<0.05),麦洼牦牛组发酵72 h乙酸、丙酸、丁酸和TVFA含量显著高于其余2组(P<0.05)。同时,麦洼牦牛组乙酸、丙酸和丁酸理论最大产量以及乙酸和丁酸产量潜在增幅显著高于其余2组(P<0.05)。3)各组发酵液pH均处于正常范围。犏牛组和麦洼牦牛组发酵24和48 h发酵液pH显著高于中国荷斯坦奶公牛组(P<0.05),麦洼牦牛组发酵24、48、72 h发酵液氨态氮含量显著高于其余2组(P<0.05),麦洼牦牛组发酵48、72 h发酵液微生物蛋白含量显著高于其余2组(P<0.05)。综上所述,麦洼牦牛、中国荷斯坦奶公牛、犏牛的瘤胃微生物发酵能力不同。

This experiment was conducted to compare the differences in rumen fermentation characteristics,methane(CH 4)production and other greenhouse gases of different breeds of beef cattle by artificial rumen gas production method.Each five healthy Maiwa yaks,Chinese Holstein steers,cattle-yaks(Tibetan yellow cattle×Maiwa yaks)with similar age(24-month-old)were selected and fed with the same diet for 42 days in the same house feeding environment,and then the rumen fluid of each breed were collected for in vitro fermentation with same diet substrate,the in vitro fermentation gas production,gas parameters,fermentation parameters and yield of CH 4,hydrogen(H 2)and carbon dioxide(CO 2)were compared.The results showed as follows:1)the gas production of each group showed an upward trend with fermentation time increased.The slowly fermentation fraction gas production and potential gas production of cattle-yak group were significantly higher than those of Maiwa yak group and Chinese Holstein steer group(P<0.05),while the rapidly fermentation fraction gas production and gas production rate of Maiwa yak group and Chinese Holstein steer group were significantly higher than those of cattle-yak group(P<0.05).2)The acetate/propionate at fermentation 24 and 48 h of Chinese Holstein steer group was significantly higher than that of other 2 groups(P<0.05),the contents of propionate and total volatile fatty acid(TVFA)at fermentation 48 h of Maiwa yak group were significantly higher than those of other 2 groups(P<0.05),and the contents of acetate,propionate,butyrate and TVFA at fermentation 72 h of Maiwa yak group were significantly higher than those of other 2 groups(P<0.05).Meanwhile,the theological maximum productions of acetate,propionate,butyrate and potential growth rates of acetate,butyrate production of Maiwa yak group were significantly higher than those of other 2 groups(P<0.05).3)The fermentation liquid pH of each group was in the normal range.The fermentation liquid pH at fermentation 24 and 48 h of cattle-yak group and Maiwa yak group was significantly higher than that of Chinese Holstein steer group(P<0.05),the fermentation liquid ammonia nitrogen content at fermentation 24,48 and 72 h of Maiwa yak group was significantly higher than that of other 2 groups(P<0.05),and the fermentation liquid microbial protein content at fermentation 48 and 72 h of Maiwa yak group was significantly higher than that of other 2 groups(P<0.05).In conclusion,the rumen microorganisms have different fermentation capabilities among Maiwa yaks,Chinese Holstein steers and cattle-yaks.