Impact of post-ruminally infused macronutrients on bovine mammary gland expression of genes involved in fatty acid synthesis, energy metabolism, and protein synthesis measured in RNA isolated from milk fat  

作　　者：Kelly Nichols AndréBannink Jurgen van Baal Jan Dijkstra 

机构地区：[1]Animal Nutrition Group,Wageningen University and Research,PO Box 338,6700,AH,Wageningen,the Netherlands [2]Wageningen Livestock Research,Wageningen University and Research,PO Box 338,6700,AH,Wageningen,the Netherlands

出　　处：《Journal of Animal Science and Biotechnology》2020年第4期1220-1231,共12页畜牧与生物技术杂志（英文版）

基　　金：conducted by Wageningen University and Research(Wageningen Livestock Research, Wageningen, the Netherlands);commissioned and funded by the Ministry of Agriculture;Nature and Food Quality (The Hague, the Netherlands) within the framework of Policy Support Research theme ‘Feed4 Foodure’(BO-31.03-005-001;TKI-AF12039);by the Vereniging Diervoederonderzoek Nederland (Rijswijk, the Netherlands)。

摘　　要：Background: Characterising the regulation of milk component synthesis in response to macronutrient supply is critical for understanding the implications of nutritional interventions on milk production. Gene expression in mammary gland secretory cells was measured using RNA isolated from milk fat globules from 6 Holstein-Friesian cows receiving 5-d abomasal infusions of saline, essential amino acids(AA), or glucose(GG) or palm olein(LG)without(LAA) or with(HAA) essential AA, according to a 6 × 6 Latin square design. RNA was isolated from milk fat samples collected on d 5 of infusion and subjected to real-time quantitative PCR. We hypothesised that m RNA expression of genes involved in de novo milk fatty acid(FA) synthesis would be differently affected by GG and LG,and that expression of genes regulating transfer of tricarboxylic acid cycle intermediates would increase at the HAA level. We also hypothesised that the HAA level would affect genes regulating endoplasmic reticulum(ER)homeostasis but would not affect genes related to the mechanistic target of rapamycin complex 1(m TORC1) or the integrated stress response(ISR) network.Results: Infusion of GG did not affect de novo milk FA yield but decreased expression of FA synthase(FASN).Infusion of LG decreased de novo FA yield and tended to decrease expression of acetyl-Co A carboxylase 1(ACC1).The HAA level increased both de novo FA yield and expression of ACC1, and tended to decrease expression of mitochondrial phosphoenolpyruvate carboxykinase(PCK2). m RNA expression of m TORC1 signaling participants was not affected by GG, LG, or AA level. Expression of the ε subunit of the ISR constituent eukaryotic translation initiation factor 2 B(EIF2 B5) tended to increase at the HAA level, but only in the presence of LG. X-box binding protein 1(XBP1) m RNA was activated in response to LG and the HAA level.Conclusions: Results show that expression of genes involved in de novo FA synthesis responded to glucogenic,lipogenic, and aminogenic substrates, whereas genes regulatin

关 键 词：Cytoplasmic crescent Endoplasmic reticulum biogenesis Mammary cell Milk fat globule Milk synthesis Tricarboxylic acid cycle 

分 类 号：S823.5[农业科学—畜牧学]