Dietary glutamine supplementation improves tissue antioxidant status and serum non-specific immunity of juvenile Hybrid sturgeon (Acipenser schrenckii ♀ × Huso dauricus♂)

Exogenous glutamine (Gln) was evaluated for its effect on antioxidation and serum non-specific immunity in juvenile Hybrid sturgeon (Acipenser schrenckii♀ × Huso dauricus♂). Seven basal diets supplemented with 0.0, 0.3, 0.6, 0.9, 1.2, 1.5% of Gln and 1.0% alanyl-glutamine (Aln-Gln) were fed to fish (initial mean weight: 22.38 ± 0.18 g) for 8 weeks, and the experiment was conducted in triplicate. Treatment of fish supplemented with 1.2, 1.5% of Gln, or 1.0% of Aln-Gln caused a significantly higher glutathione peroxidase (GPX), superoxide dismutase (SOD) activities, and glutathione (GSH) content, and lower serum malondialdehyde (MDA) levels (P < 0.05) in serum, hepatopancreas and muscles. The addition of 0.9% Gln significantly improved the serum complement-3 (C3) and complement-4 (C4) levels (P < 0.05). These findings suggest that diet supplementation with 0.9–1.2% Gln or 1.0% of Aln-Gln may enhance the activity of the antioxidant defense system and the serum non-specific immunity of juvenile Hybrid sturgeon.