为研究共轭亚油酸钙对奶牛乳脂肪的影响,选取16头泌乳中期的奶牛饲喂不同日粮,分为对照组(基础日粮)、共轭亚油酸钙低剂量组(基础日粮+ 50g/(头d))、中剂量组(基础日粮+100 g/(头·d))、高剂量组(基础日粮+200g/(头d)),试验共进行14 d,分析乳产量和乳成分.结果表明,日粮中添加共轭亚油酸钙对奶牛的乳产量、乳蛋白和乳糖没有影响,但极显著降低了乳脂肪含量(P＜0.01).检测脂肪酸组成发现奶牛的中、短链脂肪酸(C6、C10、C12、C16)含量显著降低(P＜0.05),而长链脂肪酸(C18、C18∶1)的含量显著增加(P＜0.05)；发现添加共轭亚油酸钙显著降低了各种脂肪酸的产量.研究结果显示,奶牛饲料中添加共轭亚油酸钙能够降低乳脂率,改变脂肪酸的组成.%To investigate the effect of Ca-CLA on the milk yield and quality,sixteen lactating cows were selected and allocated randomly into 4 treatments,basal diet plus 0 g/d(control) ,50 g/d(Low group) ,100 g/d(medium group) and 200 g/d(high group) Ca-CLA for two weeks, then the milk yield and composition was analyzed. The results showed that the milk yield,protein content and lactose content had no difference among the 4 treatments,while the milk fat content was significantly reduced in Ca-CLA supplement groups( P ＜0. 01) .compared with the control. The gas-liquid chromatography analysis of FAME revealed that the fatty acid composition of milk was markedly altered by Ca-CLA treatments. Adding Ca-CLA in the diet of lactating cows decreased significantly the composition of short and midium chain fatty acids( C6 ,C10,C12 and C16) ,but increased significantly the concentration of stearic (C18:0)and linoleic( C18 :2) acids in milk fat( P ＜ 0. 05 ) . The yield of total milk fatty acid reduced significantly in the Ca-CLA supplement treatments. This suggested that the supplement of Ca-CLA in dietary resulted in the reduction of milk fat rate and the alternation of milk fatty acid composition.
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