Docosahexaenoic acid increases accumulation of adipocyte triacylglycerol through up-regulation of lipogenic gene expression in pigs

Abstract

BackgroundChanging dietary fatty acid composition in modern diet influences the prevalence of obesity. Increasing evidences suggest favorable effects of n-3 PUFA for protecting against obesity and the metabolic syndrome. However, the regulation of n-3 PUFA in adipose is still unclear. Thus, this study addressed metabolism of different dietary fats in the adipose tissue of porcine model.MethodsEight-week-old cross-bred pigs were randomly assigned to three groups and fed a 2% fat diet for 30 days from either soybean oil (SBO), docosahexaenoic acid (DHA) or beef tallow. An in vitro experiment was conducted in which linoleic acid (LA), DHA or oleic acid (OA) were added to represent the major fatty acid in the SBO-, DHA- or BT- diets, respectively. Adipocytes size and lipid metabolism related genes were analyzed.ResultsPlasma triacylglycerol (TAG) was lower in DHA- than in BT-fed pigs, and the product of lipolysis, glycerol was highest in BT-fed pigs. In addition, expression of the lipolytic genes, adipose triglyceride lipase and hormone sensitive lipase was higher in BT-fed pigs and with OA treatment in vitro. DHA promoted protein kinase A activity in pigs without affecting lipolytic genes. Adipocyte cell sizes, TAG content and expression of lipogenic-related genes including, adipose differentiated related protein (ADRP) and diacylglycerol acyltransferase 1 (DGAT1) were elevated by DHA in vivo and in vitro, indicating DHA promoted adipogenesis to trap TAG in adipose tissue. Fatty acid β-oxidation genes were increased in the DHA-fed pigs.ConclusionThis effect was partly explained by the effect of DHA to promote adipogenesis to trap TAG in adipocytes and also increase expression of genes involved in adipocyte fatty acid oxidation. Therefore, our results suggest a direct effect of DHA on adipocyte metabolism, resulting in TAG turnover and fatty acid dissipation to facilitate plasma lipid uptake from the circulation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12944-017-0428-3) contains supplementary material, which is available to authorized users.

Changes in the diet composition of fatty acids and fiber affect the lower gastrointestinal motility but have no impact on cardiovascular parameters: In vivo and in vitro studies

“…It is worth mentioning that in SOY, as well as in EP diets, the predominant type of FA belongs to the long-chain PUFA, which can effectively regulate body fat by increasing the volume of adipocytes. 62,63 As previously mentioned, the EP group had elevated level of TGs in the serum. Indeed, an increased deposition of LCFAs in WAT, principally in the form of TGs, can result from increased LCFA synthesis or uptake, augmented conversion of LCFA to TGs, reduced LCFA oxidation, or changes in the TG lipolysis which in turn decreases TG or LCFAs removal.…”

“…Both SOY and EP diets displayed cellular hypertrophy, compared with the CTRL group, shown as a decrease in the number of adipocytes. It is worth mentioning that in SOY, as well as in EP diets, the predominant type of FA belongs to the long‐chain PUFA, which can effectively regulate body fat by increasing the volume of adipocytes . As previously mentioned, the EP group had elevated level of TGs in the serum.…”

Effect of Eicosapentaenoic Acid and Docosahexaenoic Acid on Myogenesis and Mitochondrial Biosynthesis during Murine Skeletal Muscle Cell Differentiation

“…These results showed that potentially upregulated adipogenesis in C2C12 cell culture could be triggered by EPA and DHA treatment. Our findings were consisted with an in vivo study, which showed upregulated adipogenesis in pig suppled with DHA ( 42 ). The upregulated adipogenesis and the decreased myogenic gene expression may indicate that overdosing EPA and DHA is associated with muscle aging.…”

Effect of diets supplemented with linseed alone or combined with vitamin E and selenium or with plant extracts, on Longissimus thoracis transcriptome in growing-finishing Italian Large White pigs

“…In literature, polyphenols have been found to influence these genes in different ways by both increasing and decreasing the expression of HSPs [ 16 ]. However, HSPs genes are not only involved in cellular stress response but they also promote muscle development and functionality via myogenesis modulation or by maintaining the structural integrity of the proteins and signaling complexes [ 22 , 64 ]. The two last above-cited pathways were found to be also related to the BP “Monocarboxylic acid biosynthetic process”.…”

“…These diet supplementations showed antioxidant and anti-inflammatory activity and positive effects against obesity and insulin-resistance [ 15 – 19 ]. In pigs, studies on diets supplemented with n -3 PUFA showed that they can influence the expression of genes involved in different biological processes (BPs) such as inflammatory response, fatty acid synthesis and oxidation [ 8 , 9 , 20 – 22 ], muscle development and differentiation, muscle protein metabolism [ 23 ] and glucose metabolism [ 21 , 24 ]. However, studies on the effects of antioxidants and polyphenols dietary supplementation have been investigated mainly in rodents, and only scarcely in farm animals so far [ 10 , 25 ].…”