Impact of dietary fat sources and feeding level on adipose tissue fatty acids composition and lipid metabolism related gene expression in finisher pigs

• The effects of dietary fat sources and feeding level on performance, adipose tissue fatty acid profile and lipid metabolism related genes expression in finisher pigs.
• Pigs fed 50.0 g/kg linseed oil diet had greater concentrations of adipose tissue PUFA.
• Pigs fed 50.0 g/animal fat diet had greater concentrations of adipose tissue SFA.
• Adipose tissue expression of ACC and FAS were down-regulated pigs fed restricted diets.
• Expression of LPL and HSL were up-regulated in pigs fed restricted diets.

The present study investigated the effects of dietary fat sources and feeding level on performance, adipose tissue fatty acid profile and lipid metabolism related genes expression in finisher pigs. A total of 128 finisher pigs [average initial body weight (BW), 81.2 ± 0.322 kg] were allotted to 4 treatments on the basis of BW. There were 4 replicates in each treatment with 8 pigs per replicate. Pigs were fed diets containing 50.0 g/kg linseed oil or animal fat, either ad libitum or restricted (15.0% less) in 2 × 2 factorial arrangement for 28 d. Dietary fat source did not affect (P>0.05) average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F). The ADG and ADFI of pigs fed ad libitum were greater (P<0.05) than that of restricted fed pigs. The G:F of restricted fed pigs was greater (P<0.05) than that of ad libitum fed pigs. Pigs fed 50.0 g/kg linseed oil diet had greater (P<0.05) concentrations of adipose tissue polyunsaturated fatty acids (PUFA) like linoleic acid and α-linolenic acid than that of pigs fed 50.0 g/kg animal fat diet. Saturated fatty acids (SFA) like palmitic acid (P<0.05), palmetoleic acid and steric acid (P<0.10) concentrations of adipose tissue were greater in pigs fed animal fat than pigs fed linseed oil. However, adipose tissue fatty acids concentrations were not affected (P>0.05) by feeding level. Adipose tissue expression of acetyl CoA carboxylase (ACC) and fatty acid synthase (FAS) were down-regulated, whereas expression of lipoprotein lipase (LPL) and hormone sensitive lipase (HSL) were up-regulated in finishing pigs fed restricted diets. However, fat sources of diet had no effects (P>0.05) on expression of ACC, FAS, LPL and HSL genes. Results obtained in the present study indicates that dietary inclusion of 50.0 g/kg linseed oil have potential to improve the adipose tissue PUFA contents, and 15.0% feed restriction resulted into down-regulation of ACC and FAS and up-regulation of LPS and HSL expression in adipose tissue.