利用乳汁体细胞研究共轭亚油酸钙对奶牛乳腺基因表达的作用

8头泌乳中期的奶牛被随机分为2组，分别是对照组（每头牛：基础日粮＋棕榈酸钙200g／d）和试验组（每头牛：基础日粮＋共轭亚油酸钙200g／d），试验期14d，检测了奶产量、乳成分，分析奶牛的血液变化，并采用荧光定量PCR对乳汁体细胞中脂蛋白脂酶（LPL）、乙酰辅酶A羧化酶（ACACA）的基因表达进行检测。结果显示，与对照组相比，试验组奶牛的乳产量、乳蛋白、乳糖和乳汁体细胞含量没有显著影响，但是显著降低了乳脂肪含量（P〈0．05），对照组和试验组奶牛乳脂肪含量分别为0．0326g／mL和0．0244g／mL。检测血液指标发现，共轭亚油酸钙显著升高了奶牛血液中高密度脂蛋白的含量（P〈0．05）。基因分析发现，试验组奶牛乳汁体细胞中LPL、ACA—CA的基因表达显著下调，表明共轭亚油酸钙抑制了奶牛乳腺细胞脂肪酸合成酶的基因表达。

Effect of CLA-Ca on lipogenic genes expression of the mammary gland in lactating cows by using milk somatic cell

Eight Holstein cows were randomly divided into two groups and received a dietary fat supplement of either Ca-salts of palm oil fatty acids （control） or Ca-salts of conjugated linoleic acid （CLA） at 200 g/d per capita for 14 d. Milk yield,milk composition and bloood parameters were determined. The gene expression of LPL and ACACA was assessed via real-time PCR. The results indicated that milk yield and the content of protein,lactose and somatic cell in milk were unaffected by treatment. The cows receiving CLA supplement had a low content of milk fat（0. 024 4 g/ mL,P〈0.05）. The content of HDL in blood was significantly increased in the cows received the CLA-Ca（P〈0.05）. The CLA diet also decreased gene expression of lipogenic enzyme of LPL,ACACA in milk somatic cell,indi- cating that CLA may inhibit the gene expression of lipogenic enzyme in mammary gland.