α-lipoic acid, tea polyphenols and their combined application affect the growth performance, biochemical indices, and inflammation-related indices of hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus) ingests a high fat-diet

High-fat diets (HD) are extensively used in aquaculture due to saving feed cost, reducing protein level, and improve better fish growth and health conditions. However, the harmful impacts of HD, especially on health, limit application of HD in aquaculture. Due to the harmful effect of HD on hepatic health can be alternatively used α-lipoic acid and tea polyphenols, which exhibit great beneficial effect. This study investigated the effects of α-lipoic acid, tea polyphenols, and their combination on growth performance, antioxidant capacity, and inflammation-related indices in hybrid groupers ( ♀ Epinephelus fuscoguttatus × ♂ E. lanceolatus ) fed a high-fat diet. A basic diet (CK group) with 50 % protein and 17 % lipid content was prepared. α-lipoic acid (LA) and tea polyphenols (TP) were used as additives, and 1000 mg/kg additive was added to the basic diet respectively, and the addition method was LA (LA group), TP (TP group), LA:TP = 1:1 (LA:TP group), LA:TP = 1:2 (LA:2TP group), LA:TP = 2:1 (2LA:TP group). Six experimental diets were fed to hybrid grouper (8.68 ± 0.22 g) for 8 weeks. These results showed that the addition of LA:TP = 1:2 (LA:2TP group) to the diet significantly increased final body weight (FBW), weight gain rate (WGR), specific growth rate (SGR) ( P < 0.05). Compared with CK, LA, TP, LA:TP and 2LA:TP groups, the serum triglyceride (TG) content in the LA:2TP group was obviously decreased ( P < 0.05), and the ratio of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) was enhanced. In addition, the complements C3 and C4 contents in liver of the LA:2TP group were obviously increased, and the total cholesterol (TC) level was significantly decreased ( P < 0.05). Meanwhile, compared with the CK group, the serum contents of malondialdehyde (MDA) in each group were markedly reduced ( P < 0.05). The results of genes related to inflammation and antioxidation showed that compared with CK, LA, TP and LA:TP groups, the antioxidant genes ( sod , cat ) and anti-inflammatory cytokine genes ( tgf-β , il-10 ) in liver and head kidney of LA:2TP group were obviously up-regulated ( P < 0.05), while those in LA, TP and LA:TP groups were obviously greater than those in CK group ( P < 0.05), and the expression level in 2LA:TP group was the lowest ( P < 0.05). Correspondingly, the pro-inflammatory cytokine genes ( il-6 , tnf-α ) in the 2LA:TP group were significantly up-regulated and greater than those in other groups ( P < 0.05), and the expression level in the LA:2TP group was the lowest ( P < 0.05). In conclusion, adding LA:TP = 1:2 can effectively enhance growth performance, improve antioxidant capacity and reduce the harmful effects of HD diet in hybrid grouper. • The high-fat Diets were supplemented with 0.1 % different proportions of LA and TP. • The combined application of LA and TP in high-fat diet promoted the growth of grouper. • LA and TP reduced the damage caused by high-fat diet by regulating physiological indicators. • The combined application of LA and TP enhances immunity through cytokine-mediated inflammatory response.