Dietary glutamine supplementation improves growth performance and intestinal digestion/absorption ability in young hybrid sturgeon (Acipenser schrenckii ♀ x Huso dauricus ♂)

Exogenous glutamine (Gln) was evaluated for its effect on growth performance, intestinal structure and function in young hybrid sturgeon (Acipenser schrenckii female x Huso dauricus male). Seven basal diets supplemented with 0, 1.00% Alanyl-Glutamine (Aln-Gln, 63.02% Gln) and 1.00, 2.00, 3.00, 4.00, 5.00% Solpro 508 (30.04% Gln) (0.30, 0.60, 0.90, 1.20, 1.50 of Gln) were fed to fish (initial mean weight: 22.38 +/- 0.18 g) for 8 weeks, Water temperature was 22.4 +/- 1.0 degrees C, Dissolved oxygen was 7.56 +/- 0.76 mg L-1, the experiment was conducted in triplicates with an initial stocking density of 15 fish per aquarium. Supplementation with Aln-Gln and Solpro 508 increased weight gain rate, intestinal fold height, digestive enzyme and Na+, K+-ATPase activities, and decreased feed conversion ratio (P < 0.05). The intestinal crypt depth decreased significantly with increasing dietary Gln supplementation, and the activities of glutathione peroxidase and superoxide dismutase, as well as glutathione content were found to be significantly higher and malondialdehyde levels were lower (P < 0.05) with increasing dietary Gln supplementation. These results provide an experimental basis for the use of Gln in improving growth performance, intestinal structure and function of juvenile sturgeon, and 1.00% Alanyl-Glutamine and 3.00%similar to 5.00% Solpro 508 supplementation in the diet is recommended.