乳品质低下是目前我国奶业发展的瓶颈，提高乳脂肪含量、改善乳脂肪酸组成，对于提升我国奶业整体发展水平，促进奶业健康发展具有重要意义。脂肪酸和激素是调控乳脂合成的重要因素，然而脂肪酸和激素对乳脂合成的影响及其作用机制仍不明确。国内外研究工作者目前关于乳成分合成的体外研究大多是以二维培养的细胞模型开展的，而二维模型由于缺失了乳腺上皮细胞的极化结构，使得研究结果不能真实反映活体内乳腺组织的代谢情况。为此，本项目以三维培养的奶牛乳腺上皮细胞为模型，研究中短链脂肪酸、18碳不饱和脂肪酸和激素对乳脂肪合成的影响，揭示促进乳脂肪合成、改善乳脂肪酸组成的理想底物供应模式；并从乳脂肪合成和转运相关基因表达，转录调控因子基因表达、蛋白表达，Akt信号通路等方面，阐明脂肪酸和激素对奶牛乳腺内乳脂肪合成的调控机理，为定向调控乳脂肪合成提供理论依据。

The low milk quality is one of limiting factor of dairy industry development in China. Increasing milk fat content and improving fatty acids composition can promote the overall development level of dairy industry. Milk fat precursors and neuroendocrine play a major role in milk fat synthesis, however the effect of fatty acids and hormones on milk fat synthesis and regulation mechanisms are still not clear. Previous studies about milk components synthesis in bovine mammary gland epithelial cell are almost conducted by two-dimensional cultivation model, however due to loss of acinar-like structures, results obtained from two-dimensional cultivation model can not really reflect mammary gland metabolism in vivo. In this research subject, three-dimensional cultivation model will be applied to study the effect of short chain, medium chain fatty acids, unsaturated fatty acids with eighteen carbon atoms and hormones on milk fat synthesis in bovine mammary gland epithelial cells, so as to reveal the ideal substrates mode which can promote milk fat synthesis and improve milk fatty acids composition. Meanwhile, the molecular mechanisms of milk fatty acids and hormones regulation milk fat synthesis will be clarified through genes expression of transcriptional regulation factors, genes associated with fatty acids and lipid synthesis, and Akt signal molecule. Protein expression of transcriptional regulation factors involved in milk fat synthesis will also be tested. Results of this subject can provide theory basis for directional regulation of milk fat synthesis.