Effects of α‐lipoic acid on growth performance, body composition, antioxidant profile and lipid metabolism of the GIFT tilapia (Oreochromis niloticus) fed high‐fat diets

Abstract

The wide use of lipid as a non‐protein energy substitute has led to lipid metabolic problems in cultured tilapia. Therefore, studies that reduce the effects of high‐fat diets in genetically improved farmed tilapia (GIFT) are required. This study evaluated the optimum level and effects of dietary α‐lipoic acid (α‐LA) on growth performance, body composition, antioxidant capacity and lipid metabolism of GIFT tilapia. The basal diet (120 g/kg lipid) was supplemented with six concentrations of α‐LA at 0 (control), L300, L600, L900, L1200 and L2400 mg/kg diet to make the experimental diets, which were fed to GIFT tilapia juveniles (initial body weight: 0.48 ± 0.01 g) for 8 weeks. The weight gain of fish improved significantly in the L300 than other dietary treatments. The intraperitoneal fat index and lipid content of fish fed on the L2400 diet decreased significantly than those fed on the control diet. The activities of superoxide dismutase and glutathione peroxidase (GSH‐Px) in serum and liver were significantly higher in fish fed on the L300 diet than the control. The reduced GSH content of fish fed on the L300 in serum and liver was significantly higher than those fed on control diet. The malondialdehyde content in serum and liver was significantly lower in L300 than in the control. The adipose triglyceride lipase gene was significantly up‐regulated in fish fed on the L2400, but the diacylglycerol acyltransferase 2 gene was down‐regulated in adipose. The liver‐type fatty acid‐binding protein gene in the liver was significantly up‐regulated in fish fed on the L300 and L600 diets. Moreover, the acyl‐coenzyme A oxidase gene in liver was significantly up‐regulated in fish fed on the L300, L600, L900 and L1200 diets. Polynomial regression analysis indicated that 439–528 mg/kg α‐LA is an appropriate dosage in high‐fat diet to improve growth performance and relieve lipid oxidative damage by accelerating lipid catabolism and reducing lipid synthesis in GIFT tilapia.

The evaluation of α‐Lipoic acid supplementation in diet on the growth performance of giant gourami ( Osphronemus goramy ) juvenile

“…The smallest MDA value in this study was found on L06 with 1.43 μmol/L, while the highest was found on L0 with 1.93 μmol/L. ALA was reported to significantly reduce the MDA level caused by the oxidative stress on Oreochromis niloticus (Xu et al., 2019), Haliotis discus hannai (Huang et al., 2019), Trachinotus marginatus (Kütter et al., 2012) and rat (Caylak et al., 2008; Şahin et al., 2006).…”

“…According to Xu et al. (2019), the concentration of ALA on 0.3–0.6 g/kg in diet increased the FI, while 0.9–2.4 g/kg concentration decreased the FI. Kütter et al.…”

“…The supplementation of ALA in feed at a certain dose improves the fish growth performance. ALA at 0.439 g/kg in diet can increase the SGR of tilapia (Xu et al., 2019). Furthermore, the supplementation of ALA at 0.7 g/kg dose significantly improved the growth performance of Eriocheir sinensis (Xu et al., 2018).…”

“…sn‐glycerol‐3‐phosphate asiltransferase‐1 and diacylglycerol O‐acyltransferase‐2), lowering the secretion of TG liver and stimulating the TG production on the rich lipoprotein condition (Butler et al., 2009). The proper ALA concentration in feed can accelerate the lipolysis and β‐oxidation (Xu et al., 2019). Similarly, study on the white mice suggests that ALA may prevent dyslipidemia induced by high‐lipid feed by enhancing the expression of genes associated with the β‐oxidation (Yang et al., 2008).…”

Dietary tea polyphenols change flesh quality with dose‐related manner in the GIFT tilapia fed with a high‐fat diet

“…In fact, these dose‐related effects had also been reported in other antioxidants, such as lipoic acid and vitamin C. Xu, Xu, et al. (2019) reported that in the GIFT tilapia fed with HFD, dietary supplementation of low‐dose α‐lipoic acid (300 mg/kg) was beneficial in improving growth and antioxidant ability, while high‐dose α‐lipoic acid (2,400 mg/kg) mainly decreased lipid content of whole fish and triglycerides content in liver, but did not affect fish growth. These similar dose‐related effects of antioxidants also occurred in red swamp crayfish (Xu et al., 2010) and Chinese mitten crab (Xu, Wang, et al., 2019).…”