为了阐明乳脂合成的影响因素及其内在分子机理,为反刍动物原料乳的优化,特别是为乳脂肪的营养调控和遗传改良提供理论依据.本试验以奶牛初乳、常乳和末乳中的乳汁体细胞为研究对象,以看家基因GAPDH为内参,对初乳、常乳和末乳中LPL、CD36、VLDLR、ACSS2、ACSL1、FABP3、ACC、FASN、SCD、ADFP、XDH和BTN1A1 mRNA进行半定量RT-PCR分析.结果发现,LPL、CD36、VLDLR、ACSS2、ACSL1、FABP3、SCD、ADFP、XDH和BTN1Al mRNA在初乳、常乳和末乳中均有表达,而ACC和FASN mRNA只在初乳中表达,常乳和末乳中均不表达；半定量结果表明,与初乳相比,常乳和末乳中LPL、CD36、VLDLR、ACSS2、ACSL1、FABP3、SCD、ADFP、XDH和BTN1Al mRNA转录水平显著降低(P＜0.05),且常乳与末乳间差异不显著(P＞0.05).研究结果提示初乳期乳腺脂肪合成能力明显高于常乳和末乳期乳腺,且脂肪合成关键酶基因的表达与细胞内脂转运和代谢的生理变化有关.%To clarify the molecular mechanism of milk fat synthesis, optimizing ruminant raw milk, particularly providing theory basis for nutrition regulation and heredity improving for milk fat. Somatic cells in colostrum milk, mature milk and involution milk were selected and housekeeping gene GAPDH was selected as reference, the semi-quantitive RT-PCR was used to analyze the expression of LPL, CD36, VLDLR, ACSS2, ACSLl, FABP3, ACC, FASN, SCD, AD-FP, XDH and BTN1A1 mRNA in milk. The results showed that the genes LPL, CD36, VLDLR, ACSS2, ACSLl, FABP3, ACC, FASN, SCD, ADFP, XDH and BTNV1A1 mRNA expressed in the colostrum milk, mature milk and involution milk. However the genes ACC and FASN were not detected in mature milk and involution milk. The relative quantitive results showed that the expression level of LPL, CD36, VLDLR, ACSS2, ACSLl, FABP3, ACC, FASN, SCD, ADFP, XDH and BTN1A1 mRNA in mature milk and involution milk were significantly decreased(P<0. 05) , compared with colostrum milk. The transcription level difference of these genes was not significant(P>0. 05) between mature milk and involution milk. These re-suits suggest that the ability of milk fat synthesis in colostrum is higher than that in mature milk and involution milk, and the expression of fatty acid synthetic key genes is related to fat transpor-tant and metabolism of cell.
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