Effects of alternative dietary oils on lipid metabolism and related gene expression in hybrid grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu )

Abstract

An 8‐week growth trial was conducted to evaluate effects of dietary oil sources on growth, enzymes activity and genes expression levels related to lipid metabolism of hybrid grouper (♀Epinephelus fuscoguttatus × ♂E. lanceolatu) juveniles. Seven iso‐lipid (97 g/kg of dry matter) and iso‐protein (503.5 g/kg of dry matter) experimental diets were formulated containing 50 g/kg fish oil (FO; acting as controls) or various vegetable oils (VOs): corn oil (CO), sunflower oil (SO), tea oil (TO), olive oil (OO), rice oil (RO) and mixed oil (MO; comprising equal amounts of these oils). Each diet was fed to triplicate groups of 40 fish for per repetition (15.09 ± 0.01 g) for 56 days. The results show that (a) alternative dietary oils had no significant effects on final weight compared with control group (p > .05); (b) compared with FO group, VOs significantly changed the contents of serum lipoproteins, cholesterol, triglycerides and the activity of liver lipid‐metabolizing enzymes (p < .05); (c) CO group had the least effect on the serum lipoproteins, triglycerides and cholesterol of grouper compared with control; the activity of liver lipid‐metabolizing enzymes in RO and control group was the closest; (d) the mRNA levels of Δ6 Fatty acid desaturase (Δ6Fad), hormone‐sensitive lipase (HSL) and lipoprotein lipase (LPL) were not significantly effected by lipid sources, but CO, TO, OO and MO significantly down‐regulated the expression of fatty acid synthetase (FAS) mRNA level in liver, while RO opposite (p < .05); (e) vegetable oil significantly up‐regulated peroxisome proliferator‐activated receptor α (PPARα) and peroxisome proliferator‐activated receptor β (PPARβ) mRNA levels, while TO and RO down‐regulated peroxisome proliferator‐activated receptor γ (PPARγ) mRNA levels (p < .05); and 6) MO significantly increased the mRNA levels of heart‐type fatty acid‐binding protein (H‐FABP) and adipocyte‐type fatty acid‐binding protein (A‐FABP) (p < .05), while other VOs had no effect on them (p > .05). In conclusion, dietary substitution of FO by VO in diet affected lipid metabolism of grouper, which may be regulated by PPARs.

Molecular Characterization, Tissue Distribution and Differential Nutritional Regulation of Three n-3 LC-PUFA Biosynthesis-Related Genes in Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

“…Similar to other cultured marine fish species, fish oil is the primary lipid source for hybrid groupers. Considering the non-sustainable reliance on fish oil to farm this species, several trials have investigated the impact of the dietary replacement of fish oil with alternatives [30][31][32][33]. However, studies related to the molecular basis of LC-PUFA biosynthesis and regulation, which could optimize the pathway to the efficient use of alternatives, are still limited in hybrid groupers.…”

Exploring the Preventive and Restorative Functions of Lactobacillus pentosus in Flesh Deterioration Caused by Oxidized Fish Oil Diets in Hybrid Grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu)

“…The peroxide value and malondialdehyde (MDA) content of OFO were 122:85 ± 1:76 mmol/kg and 121 mg/kg, respectively. The methods of diet production and the instruments used were consistent with our previous studies [23]. All ingredients were crushed and sieved through a sixty mesh sieve, then thoroughly mixed using the progressive enlargement method, then added oil and lecithin, rubbed them manually, put them into V-type vertical mixer after sieving and mixed them evenly, and then added distilled water (300 ml/kg~400 ml/kg) to mix them evenly.…”

Degradation of Muscle Quality in Hybrid Grouper (♀ Epinephelus fuscoguttatus × ♂ Epinephelus lanceolatu) Due to Oxidative Damage Caused by Ingestion of Oxidized Fish Oil

“…The annual production of grouper can reach about 200,000 tons in China, which is a high-quality source of protein. At present, research on pearl grouper is mainly focused on nutritional requirements and immunity ( 11 ), there are few reports about its muscle quality. Muscle is the primary part of human consumption, and its nutritional composition, flavor substance composition and quality are related to human health and consumption preferences.…”