Using muscle gene expression to estimate triacylglyceride deposition, and relative contributions of fatty acid synthesis and fatty acid import in intramuscular fat in cattle

作者：Dalrymple, B. P.^*; Guo, B.; Zhou, G. H.; Zhang, W.

来源：Animal Production Science, 2014, 54(9): 1436-1442.

DOI：10.1071/AN14247

• Brahman
• fatty acid binding protein 4
• Piedmontese
• stearoyl-CoA desaturase
• Wagyu

Intramuscular fat content (IMF%) in cattle influences the value of individual animals, especially for higher marbling markets. IMF is triacylglyceride (TAG) in lipid droplets in the intramuscular adipocytes. However, there are many different pathways from feed intake to the final common process of TAG synthesis and storage as IMF. To evaluate the relative importance of different pathways we compared changes in the expression of genes encoding proteins involved in the TAG and fatty acid (FA) synthesis pathways in the longissimus muscle of Piedmontese X Hereford (PxH) and Wagyu X Hereford (WxH) crosses. Based on these changes we have estimated the relative contributions of FA synthesised de novo in the intramuscular adipocyte and the uptake of circulating FA (both free and from TAG), from the diet or synthesised de novo in other tissues, to TAG deposition as IMF. We have analysed the impact of different developmental times and different diets on these processes. Increased de novo FA synthesis in intramuscular adipocytes appeared to contribute more than increased FA uptake from circulation to the additional TAG deposition in WxH compared with PxH cattle between 12 and 25 months (forage diet). Changing diet from forage to concentrate appeared to increase the importance of FA uptake from circulation relative to de novo FA synthesis for TAG synthesis in intramuscular adipocytes. These results are consistent with the literature based on analysis of lipid composition. Gene expression appears to provide a simple assay for identification of the source of FA for the deposition of IMF.

• 出版日期2014
• 单位CSIRO; 南京农业大学