近几年国际上的一些研究及项目申请人前期的研究表明，围产前期饲喂低能量水平(约为美国NRC（2001）奶牛营养需要推荐量的80%)的日粮有利于提高中等体况评分（BCS）奶牛产犊后的DMI、降低体脂动员量，但这一结论是否适用于干奶期低BCS奶牛还未见报道。本课题首先通过皮下脂肪细胞诱导培养，明确来源于不同BCS奶牛的皮下脂肪细胞的脂解活性有无差异。在此基础上，通过给低BCS围产前期奶牛饲喂不同能量水平（6.8、6.1、5.4 MJ NEL/kg）的日粮，利用活体皮下脂肪取样技术、定量PCR和Western blotting技术，检测调控体脂代谢的限速酶（激素敏感脂肪酶、脂肪酸合酶）、脂肪细胞分泌因子（瘦素、脂联素）的mRNA和蛋白质表达量；再结合血液中能量代谢关键产物的浓度，揭示日粮能量水平对低BCS奶牛体脂动员的分子调控机制，为确定干奶期低BCS奶牛的能量需要量，降低体脂动员量提供理论依据。

The latest research showed that the reduced energy density (80% of NRC（2001）requirement) of prepartum diet was effective for moderate body condition score (BCS) cows to increase DMI, decrease the adipose tissue mobilization postpartum. Whether it suites for lean dry cows need to do further research. The subcutaneous adipose tissue samples were collected from different BCS dry cows. Using an in vitro explant culture to determine the amount of stimulated glycerol release as a measure for lipolytic activity in basal conditions and after addition of isoproterenol and insulin in different concentrations. And then, lean close-up dry cows were fed with different energy level(6.8、6.1、5.4 MJ NEL/kg) diets. The subcutaneous adipose tissue samples were collected, and the mRNA abundance and protein expression of hormone-sensitive lipsase, fatty acid synthase, Leptin and adiponectin were detected with RT-PCR and Western blotting. The concentration of plasma glucose, nonesterified fatty acids, β-hydroxybutyric acid and insulin was determined. The aim of this project is to reveal the molecular regulation mechanism of diet energy density on adipose tissue mobilization of periparturient lean dairy cows, and to confirm their energy requirement prepartum, and to alleviate negative energy balance postpartum.