乙酸钠和β-羟丁酸钠对奶牛乳腺上皮细胞乳脂和乳蛋白合成相关基因表达的影响

摘要

The aim of this study was to determine the effects of sodium acetate and sodium β-hydroxybutyrate on expressions of genes involved in milk fat and protein synthesis in bovine mammary epithelial cells (BMECs). The study was consisted of two parts,and completely random single-factor designs were adopted. Part 1:single supplementation test,the supplemental concentrations of sodium acetate and sodium β-hydroxy-butyrate were 0( control),6. 00,9. 00,12. 00 and 15. 00 mmol/ L,and 0( control),0. 80,1. 60 and 2.40 mmol/ L,respectively. Part 2:mixed supplementation test,based on data from part 1,the total supple-mental concentration was the sum of optimal supplemental concentrations of sodium acetate and sodium β-hydroxybutyrate;three ratios of sodium acetate to sodium β-hydroxybutyrate(1 ∶ 1,2 ∶ 1 and 4 ∶ 1)were de-signed,and the treatment of no supplementation was used as a control group. The results showed as follows:1)compared with control group,12.00 mmol/ L sodium acetate significantly increased the expression levels of acetyl-CoA carboxylase(ACC),fatty acid synthetase(FAS),diacylgycerol acyltransferase(DGAT),acetyl-CoA synthetase 2(ACSS2),peroxisome prolifertor receptor(PPARG),κ-casein(CSN3)genes and the con-tent of triglyceride(TAG)in BMECs(P<0.05). 2)Compared with control group,2.40 mmol/ L sodium β-hydroxybutyrate significantly increased the expression levels of ACC,FAS,ACSS2,PPARG and mammalian target of rapamycin(mTOR)genes and the content of TAG in BMECs(P<0.05). 3)When the ratios of sodi-um acetate to sodium β-hydroxybutyrate were 2∶1 and 4 ∶1,The supplementation of sodium acetate and sodiumβ-hydroxybutyrate at different mixed ratios significantly up-regulated the expression levels of genes involved in milk fat synthesis at different extents. The content of TAG in BMECs were significantly increased compared with when the ratio was 1 ∶ 1 and control group( P < 0. 05). In conclusion,the mixed supplementation of 9.60 mmol/ L sodium acetate and 4.80 mmol/ L sodium β-hydroxybutyrate are optimal,considering its simula-tive effects on milk fat and protein synthesis.%本试验旨在研究乙酸钠和β-羟丁酸钠对奶牛乳腺上皮细胞（BMECs）乳脂和乳蛋白合成相关基因表达的影响。试验分2部分，均采用单因子完全随机试验设计。第1部分，单独添加试验，乙酸钠的添加浓度分别为0（对照）、6．00、9．00、12．00和15．00 mmol/ L，β-羟丁酸钠的添加浓度分别为0（对照）、0．80、1．60和2．40 mmol/ L。第2部分，混合添加试验，以单独添加试验得出的乙酸钠和β-羟丁酸钠的适宜浓度，二者之和为总添加浓度，设定3种不同配比，即乙酸钠∶β-羟丁酸钠分别为1∶1、2∶1和4∶1，对照组不添加乙酸钠和β-羟丁酸钠。结果表明：1）与对照组相比，12．00 mmol/ L 乙酸钠能够显著提高 BMECs 乙酰辅酶 A 羧化酶（ ACC）、脂肪酸合成酶（FAS）、二酰甘油酰基转移酶（ DGAT）、乙酰辅酶 A 合成酶2（ ACSS2）、过氧化物酶体增殖物激活受体（PPARG）、κ酪蛋白（CSN3）和雷帕霉素靶蛋白（ mTOR）基因的表达量及甘油三酯（TAG）的含量（ P ＜0．05）。2）与对照组相比，2．40 mmol/ L 的β-羟丁酸钠能够显著提高BMECs ACC、FAS、ACSS2、PPARG、mTOR 基因表达量及 TAG 含量（P＜0．05）。3）添加不同配比的乙酸钠和β-羟丁酸钠均不同程度地促进了乳脂合成相关基因的表达，乙酸钠∶β-羟丁酸钠为2∶1和4∶1时，BMECs 中 TAG 含量显著高于为1∶1时和对照组（ P＜0．05）。综合各项指标，以9．60 mmol/ L乙酸钠和4．80 mmol/ L β-羟丁酸钠混合添加对奶牛乳腺上皮细胞乳脂和乳蛋白合成的促进效果较好。