日粮精粗比对泌乳奶牛瘤胃纤维降解酶活性及血液指标的影响

Effects of dietary concentrate-to-forage ratio on the activity of ruminal celluolytic enzyme and blood parameters of lactating dairy cows

选择4头安装有瘤胃瘘管的泌乳奶牛,按4×4拉丁方设计,研究日粮精粗质量比约为30∶70的“高低质粗料型”日粮、30∶70的混合型高青贮日粮、50∶50的精粗料比例相当的日粮及65∶35的高精料日粮等4种不同精粗比日粮对瘤胃纤维降解酶活性及血液指标的影响。结果显示,奶牛采食4种精粗比不同的日粮,均能达到满足纤维降解及纤维分解菌生长要求的瘤胃pH值;日粮精粗比对微晶纤维素、羧甲基纤维素酶、纤维二糖酶和木聚糖酶等瘤胃纤维降解酶活性的影响差异不显著(P>0.05),对奶牛颈静脉血中血浆葡萄糖浓度和血清生长激素、胰岛素、胰高血糖素浓度亦无显著(P>0.05)影响。说明4种精粗比日粮对奶牛瘤胃纤维降解酶活性及上述血液指标没有影响。

Effects of dietary concentrate-to-forage ratio on the activity of ruminal celluolytic enzyme and blood parameters were evaluated by selecting four primiparous Holstein cows with permanently ruminal cannula according to 4 × 4 Latin square design with 20-d period. Dietary concentrate-to-forage ratios were 30 ： 70,30 ： 70,50 ： 50,and 65 ： 35,respectively. The result showed that ruminal fluid pH matched up to the condition of fiber degradation and the growth of cellulolytic bacterium when cows were fed four diets with different concentrate-to-forage ratios; there was no significant difference （P〉0.05） for the activity of cellulase, glucanase,cellobiase and xylanase involved in ruminal fiber degradation and the concentration of plasma glucose and serum growth hormone, nor for the insulin and glucagon in the jugular vein of cows among four dietary treatments. The results indicated that four diets with different concentrate-to-forage ratios did not influence the activity of ruminal celluolytic enzyme of lactating dairy cows and blood parameters mentioned above.