The effect of dietary paeonol on growth performance, antioxidant enzyme activities and gene expressions of Genetic Improvement of Farmed Tilapia juveniles (Oreochromis niloticus)

Abstract

This experiment was conducted to determine the effect of dietary paeonol levels on growth performance, serum biochemical parameters, antioxidant enzyme activities and transcriptional expression of antioxidant- and immune-related genes in Genetic Improvement of Farmed Tilapia (GIFT) juveniles. Six diets supplemented with 0, 60, 120, 240, 480 and 960 mg kg−1 paeonol were formulated, and each diet was randomly assigned to three replicate groups of 25 fish with an average initial weight of 23.10 ± 0.90 g for 53 days. Our results showed that weight gain (WG) increased first and then decreased with the increase of dietary paeonol levels. Serum alkaline phosphatase (ALP), albumin (ALB) and total protein (TP) were significantly increased as the increasing dietary paeonol levels. Lactate dehydrogenase (LDH) contents, alanine aminotransferase (ALT) and aspartate transaminase (AST) activities displayed a trend of decreasing or significantly decreasing in the paeonol-added groups. Supplemental paeonol in diets significantly elevated the activities of catalase (CAT), glutathione peroxidase (GPx) and Lysozymes (LYZ) in both serum and liver, while decreased the malondialdehyde (MDA) values. Furthermore, the levels of dietary paeonol had significant effects on the mRNA expression of antioxidant genes (including CAT, GPx, Maf, HMOX1) and immune genes (including irak1, IL-8, CC1, LYZ). These data suggested that dietary paeonol could improve the growth performance and some serum biochemical indices of GIFT, enhanced the antioxidant enzyme activities, and induced the expression of antioxidant- and immune-related genes. Analysis based on broken-line regression, 90.55 mg kg−1 paeonol would be suitable for tilapia juveniles.

Keywords

• Tilapia
• Dietary paeonol
• Growth
• Antioxidant
• Gene expression