Short-Term Responses to Fatty Acids on Lipid Metabolism and Adipogenesis in Rainbow Trout (Oncorhynchus mykiss)

Abstract

Fish are rich in n-3 long-chain polyunsaturated fatty acids (LC-PUFA) such as eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Due to the increasing use of vegetable oils (VO), their proportion in diets has lowered, affecting lipid metabolism and fillet composition. Rainbow trout cultured preadipocytes were treated with representative FA found in fish oils (EPA and DHA) or VO (linoleic, LA and alpha-linolenic, ALA acids), while EPA and LA were also orally administered, to evaluate their effects on adipogenesis and lipid metabolism. In vitro, all FA increased lipid internalization, with ALA producing the highest effect, together with upregulating the FA transporter fatp1. In vivo, EPA or LA increased peroxisome proliferator-activated receptors ppara and pparb transcripts abundance in adipose tissue, suggesting elevated β-oxidation, contrary to the results obtained in liver. Furthermore, the increased expression of FA synthase (fas) and the FA translocase/cluster of differentiation (cd36) in adipose tissue indicated an enhanced uptake of lipids and lipogenesis de novo, whereas stable or low hepatic expression of genes involved in lipid transport and turnover was found. Thus, fish showed a similar tissue metabolic response to the short-term availability of EPA or LA in vivo, while in vitro VO-derived FA demonstrated greater potential inducing fat accumulation.

Farmed Gilthead Sea Bream (Sparus aurata) by-Products Valorization: Viscera Oil ω-3 Enrichment by Short-Path Distillation and In Vitro Bioactivity Evaluation

“…Many studies have underlined the beneficial effects of fish oils in cellular homeostasis, oxidative stress, and cardiovascular disease prevention and general health [ 77 , 78 ], thus rendering the test of these properties for new produced oils very useful in view of its commercialization. An in vitro test is an ideal and consolidated experimental model system that is able to confirm in reliable and fast way some bioactive properties exerted by natural compounds, such as refined oils, in view of its further industrial applications [ 35 , 38 , 79 ]. In view of these considerations, toxicity, antioxidant properties, and modulation of adipogenesis were the main issues we considered in our work to address these oils in human consumption and fish meal inclusion.…”

“…On the contrary, EFA treatment promoted a significant lipid accumulation ( Figure 4 d). The accumulation of cytoplasmatic lipid droplets was moderate during the first three days, but it increased significantly on the fourth day up to a total adipocyte hypertrophy on the seventh day ( Figure 4 d), thus suggesting that EFA may stimulated fat uptake and fat cytoplasm accumulation [ 38 ].…”

“…In particular, in the wide range of beneficial effects, several studies have suggested that ω-3 PUFA also has antioxidant, anti-inflammatory, and anti-adipogenic effects. These effects, with important nutritional and nutraceutical implications, have been demonstrated in vitro on different cell lines [ 35 , 36 , 37 , 38 ].…”

Lipid Deposition and Mobilisation in Atlantic Salmon Adipocytes

“…The radiolabeled PA was obtained from American Radiolabeled Chemicals, Inc. (St. Louis, MO, USA), and the non-radiolabeled FAs were all supplied from Sigma-Aldrich (St. Louis, MO, USA). The doses were selected based on previous in vitro studies performed on adipocytes [64,65] and based on extensive experience in our laboratory from previous studies.…”

Genistein Induces Adipogenic and Autophagic Effects in Rainbow Trout (Oncorhynchus mykiss) Adipose Tissue: In Vitro and In Vivo Models

“…Intracellular neutral lipid accumulation was analyzed by ORO staining, performed as in previous studies [28,90]. After 72 h treatments, cells were fixed for 1 h with 10% formalin and stained with 0.3% ORO (O0625, Sigma-Aldrich, Tres-Cantos, Spain) diluted in 36% triethyl phosphate during 2 h. After washing the excessive dye with distilled water and resuspending it in isopropanol, the quantification of the lipid content was calculated as the quotient of the absorbance measured at 490 nm by the one at 630 nm in duplicate 96-wells, using a microplate reader (Tecan Infinite M200, Männedorf, Switzerland).…”