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The effect of dietary fat on lipogenic gene expression in farm animals, and especially the effect of high medium-chain saturated fatty acids (MCFA), remains poorly understood. The present study was conducted to assess whether the partial replacement of feed energy by vegetable oils containing MCFA and n-6 polyunsaturated fatty acids (PUFA) would modify lipogenic gene expression and other parameter of fat metabolism in pigs. A total of 18 crossbred male pigs (aged 100 ± 5 days; 17 - 19 kg BW) were housed in groups (3 animals/pen) and randomly assigned to one of three experimental diets (6 animals/group) for 60 days: (i) Control diet (CON); (ii) a diet with sunflower oil (SO) or (iii) a diet with coconut oil (CO). In diets SO and CO, 10% of the feed energy was replaced by the respective oils. At the beginning and end of the experimental feeding period, the subcutaneous adipose tissue collected from the ham region for gene expression, fatty acid composition and histology analysis. Also, blood samples were collected to determine the serum lipid profile.
The experimental treatment did not influence pigs performance. In blood serum, an increased content of total cholesterol was observed for SO and CO fed animals, whereas no significant changes for total triglycerides and different lipoprotein fractions were detected. The fatty acid composition of adipose tissue was significantly modified, with an increased content of MCFA (8.59%) and n-6 PUFA (19.41%) in CO and SO fed pigs, respectively. Gene expression for fatty acid synthase was decreased (P < 0.05) for SO (0.37) and CO (0.87) fed pigs regarding the CON group (1.05); for stearoyl CoA desaturase and sterol regulatory element binding protein, a depression was observed only in SO feeding group (0.51 and 0.53, respectively) but not in CO. Neither the adipocytes diameter nor the adipocytes volume was influenced by the dietary treatments (P > 0.05).
The results of present study suggest that the type of dietary fat can modulate the adipose tissue gene expression and fatty acid composition differentially, with minimal effect on histology and serum lipid profile.
MN Harihara-Iyera, BC Sarmahc, MK Tamulia, A Dasa, D Kalitac. 2012. Effect of dietary sunflower oil and coconut oil on adipose tissue gene expression, fatty acid composition and serum lipid profile of grower pigs. Archives of Animal Nutrition, 66(4):271-282. http://dx.doi.org/10.1080/1745039X.2012.683324.