季节变化对放牧藏系绵羊瘤胃发酵特性及产甲烷菌的影响

Effects of Seasonal Shift on Quantity of Rumen Methanogen and Fermentation of Grazing Tibetan Sheep

在春、夏、秋和冬季分别随机选取3只随群放牧藏系绵羊,通过常规养分分析法和实时定量PCR技术,研究牧草养分的季节变化对瘤胃发酵特性及瘤胃产甲烷菌的影响。结果表明:①不同季节藏羊瘤胃液挥发性脂肪酸的生成量随季节而变化,但对瘤胃发酵模式没有影响,仍然呈乙酸发酵模式。夏季总挥发性脂肪酸、丙酸、丁酸和戊酸浓度极显著高于其他季节(P<0.01);冬季乙酸浓度和乙酸/丙酸极显著高于其他季节(P<0.01);夏季和秋季乙酸浓度差异不显著(P>0.05),但极显著高于春季(P<0.01);秋季丙酸浓度极显著高于冬季和春季(P<0.01);秋季乙酸/丙酸极显著高于春季和夏季(P<0.01),春季极显著高于夏季(P<0.01)。②瘤胃产甲烷菌质量浓度也随季节而变化,夏季瘤胃总产甲烷菌质量浓度极显著高于春季、冬季和秋季(P<0.01),秋、冬季节差异不显著(P>0.05),但极显著高于春季(P<0.01)。

In order to study the effects of seasonal shifted grass nutrition on fermentation characters and quantity of methanogen in rumens,grass samples and rumen content samples of three grazing Ti- betan sheep in each season were collected to analyze the grass nutrition and monitor the quantity change of methanogen in rumens by conventional methods and real time PCR. Results showed 1）the quantity of volatile fatty acids （VFA） in sheep rumen was changed with seasonal shift. The fermenta- tion model was not changed and remained acetate fermentation model in rumen. Contents of TVFA, propionate, butyrate and valerate in summer were significantly higher than that in other seasons（P〈0.01）. The contents of acetate and acetate/propionate in winter were significantly higher than that in other seasons（P〈0. 01）, the contents of acetate in summer was significantly higher than that in spring（P〈0.01）, it was not significant different（P〉0.05）between summer and winter. The con- tents of acetate in autumn was significantly higher than that in winter and spring（P〈0.01）. Acetate/propionate in autumn was significantly higher than that in spring and summer（P〈20.01）, and Acetate/ Propionate in spring was significantly higher than that in summer（P〈0.01）. 2）The quantity of methanogen in grazing Tibetan sheep rumen was changed with seasonal shift and it was significantly higher in summer than in others seasons（P〈0.01）, the quantity of methanogen in autumn and winter were significantly higher than that in spring（P〈0.01）, but there was no significant difference（P〉0.05）between autumn and winter.