Comparative analysis of effects of dietary arachidonic acid and EPA on growth, tissue fatty acid composition, antioxidant response and lipid metabolism in juvenile grass carp,Ctenopharyngodon idellus

Abstract

Four isonitrogenous and isoenergetic purified diets containing free arachidonic acid (ARA) or EPA (control group), 0·30 % ARA, 0·30 % EPA and 0·30 % ARA+EPA (equivalent) were designed to feed juvenile grass carp (10·21 (sd 0·10) g) for 10 weeks. Only the EPA group presented better growth performance compared with the control group (P<0·05). Dietary ARA and EPA were incorporated into polar lipids more than non-polar lipids in hepatopancreas but not intraperitoneal fat (IPF) tissue. Fish fed ARA and EPA showed an increase of serum superoxide dismutase and catalase activities, and decrease of glutathione peroxidase activity and malondialdehyde contents (P<0·05). The hepatopancreatic TAG levels decreased both in ARA and EPA groups (P<0·05), accompanied by the decrease of lipoprotein lipase (LPL) activity in the ARA group (P<0·05). Fatty acid synthase (FAS), diacylglycerol O-acyltransferase and apoE gene expression in the hepatopancreas decreased in fish fed ARA and EPA, but only the ARA group exhibited increased mRNA level of adipose TAG lipase (ATGL) (P<0·05). Decreased IPF index and adipocyte sizes were found in the ARA group (P<0·05). Meanwhile, the ARA group showed decreased expression levels of adipogenic genes CCAAT enhancer-binding protein α, LPL and FAS, and increased levels of the lipid catabolic genes PPAR α, ATGL, hormone-sensitive lipase and carnitine palmitoyltransferase 1 (CPT-1) in IPF, whereas the EPA group only increased PPAR α and CPT-1 mRNA expression and showed less levels than the ARA group. Overall, dietary EPA is beneficial to the growth performance, whereas ARA is more potent in inducing lipolysis and inhibiting adipogenesis, especially in IPF. Meanwhile, dietary ARA and EPA showed the similar preference in esterification and the improvement in antioxidant response.

Effects of dietary lipid level on growth, fatty acid profiles, antioxidant capacity and expression of genes involved in lipid metabolism in juvenile swimming crab, Portunus trituberculatus

“…In the present study, the contents of MDA both in haemolymph and hepatopancreas increased as dietary lipid increased from 5•8 to 15•1 %, indicating that lipid peroxidation products increased with increased dietary lipid level, possibly reflecting higher n-3 LC-PUFA levels. Overall, these results demonstrated that relatively high dietary lipid levels led to an increased risk of peroxidation and imposed a peroxidation burden (36,37) .…”

Effects of dietary lipid levels on growth, fatty acid composition, antioxidant status and lipid metabolism in juvenileOnychostoma macrolepis

“…At the end of the feeding trial, the fish were fasted for 24 hr and anaesthetized with tricaine methanesulfonate (MS222; 0.06 g/L; Tian et al, ). The body weights, lengths (18 fish/tank) and hepatopancreas weights of the fish (12 fish/tank) were measured to calculate their condition factors and hepatosomatic index.…”

“…At the end of the feeding trial, the fish were fasted for 24 hr and anaesthetized with tricaine methanesulfonate (MS222; 0.06 g/L; Tian et al, 2017…”

Feeding Faba Beans (Vicia faba L.) Reduces Myocyte Metabolic Activity in Grass Carp (Ctenopharyngodon idellus)

“…Afterward, 5-µm sections were cut with a rotary microtome (RM2235, Leica, Germany), mounted on glass slides, and stained with H&E. Histological samples were observed and photographed using an upright microscope (Leica biosystems, Wetzlar, Germany). The average myocyte size per image was quantified using Photoshop (Adobe) as previously described (Tian et al, 2017). An average value across three non-overlapping images (three/section) was calculated for each group.…”