The Effect of Dietary Lipid Supplementation on the Serum Biochemistry, Antioxidant Responses, Initial Immunity, and mTOR Pathway of Juvenile Tilapia (Oreochromis niloticus)

Abstract

The objectives of this study were to investigate the effect of different dietary lipid levels on the serum biochemistry, antioxidant responses, initial immunity, and mTOR pathway of juvenile genetic improvement-farmed tilapia (GIFT, Oreochromis niloticus). Six groups of the juveniles (initial body weight 20.66 ± 1.33 g) in triplicate were fed for 90 days using six iso-nitrogen diets with different lipid levels (0.35%, 3.35%, 6.35%, 9.35%, 12.35%, and 15.35%). The main results were as follows: Compared with the control group (0.35%), the diets with different lipid supplementation significantly improved (p < 0.05) the contents of total protein (TP), albumin (ALB), globulin (GLB), glucose (GLU), triglyceride (TG), total cholesterol (T-CHO), high-density lipoprotein (HDL), low-density lipoprotein (LDL), total antioxidant capacity (T-AOC), malondialdehyde (MDA), complement 3 (C3), and immunoglobulin M (IgM), the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT), lysozyme (LYZ), and alkaline phosphatase (ALP), the expression level of phosphatidylinositol-3-kinase (PI3K), Akt protein kinase B (Akt), and mammalian target of rapamycin (mTOR) genes in juvenile tilapia. However, diets with different lipid supplementation significantly reduced (p < 0.05) the expression level of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) genes of juvenile tilapia. In conclusion, the with different lipid supplementation could significantly affect the serum biochemistry, antioxidant responses, initial immunity, and mTOR pathway of juvenile tilapia.

Serum biochemistry, fatty acids, lipid metabolism, antioxidants, and inflammation response were significantly affected by feeding different marine red yeast supplementation in juvenile tilapia (GIFT strain, Oreochromis niloticus)

“…These factors are important inflammatory mediators in animals and play a significant role in immune regulation. Their expression levels are often used as indicators of the body's inflammatory response (Liu et al, 2023). In this study, adding marine red yeast to feed significantly increased the expression of inflammatory response genes and improved the immune response of juvenile GIFT.…”

“…According to the method of Liu et al (2023), the serum biochemical parameters and lipid metabolism enzyme activity were determined using an enzyme-linked immunosorbent assay (ELISA) analyzer (RT-6100, Rayto, Shenzhen, China) and assay kits. The content of total protein (TP, g/L) in the serum of juvenile tilapia was determined using the Coomassie blue staining method.…”

“…According to the method of Liu et al (2023), fatty acids in the muscle were determined by gas chromatography (GC, Agilent Technologies, Inc., Santa Clara, California, USA). The determination of fatty acids was as follows: First, the lipids were extracted and purified; second, the lipids were saponified; third, the fatty acids were methylated; fourth, the extracted fatty acids underwent methyl esterification; and fifth, fatty acids were determined using a gas chromatograph.…”