Evaluation of dietary genistein on the antioxidant capacity, non-specific immune status, and fatty acid composition of common carp (Cyprinus carpio .L)

Abstract

This experiment was performed to determine the effect of dietary genistein on the growth, antioxidation, immunity, as well as lipid metabolism of common carp (Cyprinus carpio.L). Six experimental feeds containing 0 (control group), 25, 50, 100, 500 or 1000 mg/kg of genistein were respectively formulated. The feeds were randomly assigned to triplicate tanks with 30 fish (initial weight (20.59 ± 0.69) g) for 8 weeks. All the growth parameters were significantly improved by supplementation with 100 and 500 mg/kg genistein. The alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were reduced, but the acid phosphatase (ACP) activity was increased in serum of the 100 mg/kg genistein group. The total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and catalase (CAT) levels were significantly increased in serum when the feed was supplemented with 500 mg/kg of genistein. The total cholesterol (TC), triglyceride (TG), and low–-density lipoprotein cholesterol (LDL-C) levels in serum were reduced in the genistein (100 and 500 mg/kg) supplement groups. The mRNA expression levels of the pro-inflammatory cytokines, such as interleukin 1 (il-1), the nuclear factor kb (nf-kb), and il-8 were reduced, but the expressions of anti-inflammatory cytokines, such as transforming growth factor-b (tgf-b) and il-10 were enhanced in the head kidney and spleen tissues after genistein supplementation. Furthermore, the immune enhancement of genistein was confirmed by increasing the survival rate of common carp to Aeromonas hydrophila challenge. In addition, the fatty acids profile in the liver and muscle of common carp indicated that an increase of muscle total PUFA, especially n-3 PUFA and HUFA levels in 100 or 500 mg/kg genistein supplement groups. Meanwhile, after the feeding trial, the amount of total PUFA in the liver was significantly elevated in the 500 mg/kg genistein group. As the acsl6 and elovl5 mRNA expressions in the liver were enhanced after genistein treatment, the biosynthesis ability of endogenous HUFA may be enhanced. Moreover, lipogenesis-related genes in the liver were down-regulated after genistein treatment. Therefore, 100 and 500 mg/kg of genistein can significantly improve growth, body composition and lipid metabolism, enhance the antioxidant and immunity of common carp.