Effects of γ‐aminobutyric acid supplementation on the growth performance, serum biochemical indices and antioxidant status of pharaoh cuttlefish,Sepia pharaonis

Abstract

This study evaluated the effects of dietary γ-aminobutyric acid (GABA) on the growth performance, serum biochemical indices and antioxidant status of pharaoh cuttlefish, Sepia pharaonis. Cuttlefish were cultured in open-culturing cement pool systems for 8 weeks. Six practical diets supplemented with graded levels of GABA (0, 20, 40, 60, 80 and 100 mg/kg) were formulated. Each diet was randomly assigned to triplicate groups of 60 cuttlefish (mean weight: 10.33 g), the cuttlefish were fed two times per day to apparent satiation. The results showed that the specific growth rate (SGR), weight gain (WG) and feed efficiency (FE) significantly increased with dietary GABA supplementation (p < .05). The survival rate (SR) and protein content in muscle significantly increased when 58.9 mg/kg GABA supplied. Moreover, the nitric oxide (NO) content and acid phosphatase (ACP) activity in serum were significantly increased with dietary GABA supplementation (p < .05), while the activity of aspartate aminotransferase (AST) in serum decreased significantly when supplied with GABA at 58.9 mg/kg (p < .05). In addition, dietary GABA improved antioxidation activity by significantly increasing the activities of superoxide dismutase (SOD) and catalase (CAT) but decreasing malondialdehyde (MDA) levels in the liver and gill (p < .05). On the basis of the quadratic regression analysis of FE, the optimum content of dietary GABA in S. pharaonis was estimated to be 55.3 mg/kg. The findings of this study demonstrated that dietary GABA had a positive effect on the growth performance, serum biochemical indices and antioxidant status of S. pharaonis.