不同饲养条件下牦牛瘤胃内VFA的变化

THE RUMEN FLUID VFA OF CHINESE YAK VARYING WITH DIFFERENT RAISING CONDITIONS

用气相色谱法比较了放牧条件下各主要季节及舍饲条件下牦牛瘤胃液挥发性脂肪酸(VFA)组成及含量。结果表明:总酸(TVFA)以青草期为最高,各期之间均呈高度显著差异(P<0.01),排列顺序为:青草期>舍饲期>枯黄期>枯草期;丙酸仍以青草期高于其它三组(P<0.01),舍饲期丙酸与桔黄期比较无差异(P>0.05),但均高于枯草期(P<0.01);乙酸/丙酸比例,虽然青草期显著高于舍饲期(P<0.01),但发酵类型变化不大。冬季采食量不足是造成 TVFA 下降的重要因素。

Chinese yak rumen fluid VFA were seperated by gas-chromatographyand quantified using the area ratio of each respective peak to the internalstandard.We compared VFA under main grazing seasons of Qinghai grass-land and housing condition.The results indicated,the total VFA (TVFA) of green grass period(GGP)was highest,there wera greatly evident differ-ences(P<0.01)among GGP,withered arid yellow period(WYP),with-ered period (WP),housing condition group (HCG);the sequence of VFAconcentration was GGP,HCG,WYP,WP.The propionic acid concentration of GGP was greatest (P<0.01)among the others,no differenee(P>0.05)was observed between HCG andWYP,both of them greater(P<0.01)than WP.There was great differ-ence(P<0.01)on the proportion of C_2/C_3 between GGP and HCG.There was no sufficient forage for yak is a main factor of the VFAdecreasing in winter.