Impact of dietary protein on lipid metabolism-related gene expression in porcine adipose tissue

Abstract

BackgroundHigh dietary protein can reduce fat deposition in animal subcutaneous adipose tissue, but little is known about the mechanism.MethodsSixty Wujin pigs of about 15 kg weight were fed either high protein (HP: 18%) or low protein (LP: 14%) diets, and slaughtered at body weights of 30, 60 or 100 kg. Bloods were collected to measure serum parameters. Subcutaneous adipose tissues were sampled for determination of adipocyte size, protein content, lipid metabolism-related gene expression, and enzyme activities.ResultsHP significantly reduced adipocyte size, fat meat percentage and backfat thickness, but significantly increased daily gain, lean meat percentage and loin eye area at 60 and 100 kg. Serum free fatty acid and triglyceride concentrations in the HP group were significantly higher than in the LP group. Serum glucose and insulin concentrations were not significantly affected by dietary protein at any body weight. HP significantly reduced gene expression of acetyl CoA carboxylase (ACC), fatty acid synthase (FAS) and sterol regulatory element binding protein 1c (SREBP-1c) at 60 kg and 100 kg; however, the mRNA level and enzyme activity of FAS were increased at 30 kg. HP promoted gene and protein expression and enzyme activities of lipoprotein lipase (LPL), carmitine palmtoyltransferase-1B (CPT-1B), peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte-fatty acid binding proteins (A-FABP) at 60 kg, but reduced their expression at 100 kg.Gene expression and enzyme activity of hormone sensitive lipase (HSL) was reduced markedly at 60 kg but increased at 100 kg by the high dietary protein. Levels of mRNA, enzyme activities and protein expression of ACC, FAS, SREBP-1c and PPARγ in both LP and HP groups increased with increasing body weight. However, gene and protein expression levels/enzyme activities of LPL, CPT-1B, A-FABP and HSL in both groups were higher at 60 kg than at 30 and 100 kg.ConclusionFat deposition in Wujin pigs fed high dietary protein for 25 weeks was reduced mainly by depression of lipogenic gene expression. The mechanism of lipid transport, lipolysis and oxidation in adipose tissue regulated by dietary protein appeared to be different at 60 kg and 100 kg body weights.

Antihyperlipidemic effects of hydroxyethyl methylcellulose with varying viscosity in mice fed with high fat diet

“…Berndt et al (2007) reported that increased FAS gene expression in human adipose tissue was significantly related to visceral fat accumulation. Likewise, the down-regulation of ME and G6PD gene expressions has been associated with the reduction in lipogenic activity resulting in decreased fat accumulation (Zhao et al, 2010). The CPT activity did not significantly change in HF and HF-HV groups, but decreased in HF-MV and HF-LV groups relative to that of the NC group.…”

Impacts of Macronutrients on Gene Expression: Recent Evidence to Understand Productive and Reproductive Performance of Livestock

“…Studies have demonstrated that SCD facilitates more accessible pool of monounsaturated fatty acids in adipose tissue and therefore, regulate the synthesis of triglyceride (Postic and Girard, 2008). Furthermore, adipocyte-fatty acid binding proteins (A-FABP) and lipoprotein lipase (LPL) have identified as regulators of lipid metabolism in adipose tissue because they are able to modulate the expression of genes involved in lipid metabolism or fatty acids transportation (Zhao et al, 2010). Despite an increase of dietary energy intake (in terms of fat) can improve the digestion and absorption of other nutrients, it may also upregulate the expression of lipogenic genes which eventually cause an increased de novo synthesis of free fatty acid (FFA) resulting higher accumulation of subcutaneous adipose tissue .…”

Detection of differentially expressed genes in the longissimus dorsi of Northeastern Indigenous and Large White pigs

“…FABP4 has been proposed to play a critical role in the balance between lipolysis and lipogenesis in adipocytes (Chmurzynska, 2006). As it appears late during adipogenesis (Spiegelman et al, 1983), FABP4 content has recently been suggested as a valuable marker for lipid content and adipocyte number (Zhao et al, 2010). The gene, acting as a key mediator of intracellular transport and metabolism of fatty acids, is expressed in a differentiation-dependent fashion in adipocytes (Amri et al, 1991;Gregoire et al, 1998).…”