Dietary selenium requirement of juvenile oriental river prawn Macrobrachium nipponense

Selenium (Se) is an essential nutrient for crustaceans. The dietary selenium requirement of juvenile oriental river prawn Macrobrachium nipponense was evaluated. Yeast-selenium was added to basal semi-purified diet at six levels to make diets with the concentration of 0.11, 0.31, 0.47, 0.59, 0.88 and 1.17 mg Se kg^{− 1}. These diets were fed to juvenile prawns (initial weight 0.133 ± 0.003 g) in quintuplicate for 8 weeks. Our results indicated that the growth performance of prawn was significantly affected by dietary selenium. Prawns fed the 0.47 and 0.59 mg Se kg^{− 1} diets achieved the highest weight gain rate (WGR), whereas the deficiency (0.11 mg kg^{− 1}) and excess (1.17 mg kg^{− 1}) of Selenium inhibited their growth. Whole-body and muscle Se concentrations generally increased with the level of dietary Se. The highest concentrations in body and muscle were observed in the prawns fed the 1.17 mg kg^{− 1} diet, which were significantly higher than those of prawns using 0.11, 0.31, 0.47 and 0.59 mg kg^{− 1} diets. Selenium also affects the activity of antioxidant enzymes. The activities of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were significantly higher in prawns fed with 0.31, 0.47 and 0.59 mg Se kg^{− 1} than other groups, whereas the maleic dialdehyde (MDA) content had the opposite pattern from GSH-Px activity. Significantly elevated glutathione reductase (GR) activity and reduced glutathione (GSH) content were found in prawns fed the 0.31, 0.47, 0.59 and 0.88 mg kg^{− 1} diets. The prawns fed with 0.31–0.88 mg Se kg^{− 1} exhibited the highest total antioxidant competence (T-AOC activity), which was significantly higher than 1.17 mg kg^{− 1} group. Furthermore, selenium is involved in prawn immune competence. Serum phenoloxidase (PO) and lysozyme activities in prawns fed the 0.31, 0.47, 0.59 and 0.88 mg Se kg^{− 1} diets were significantly higher than those fed the 0.11 and 1.17 mg Se kg^{− 1} diets. The minimum dietary selenium requirements for maximal growth and antioxidant ability of juvenile oriental river prawn were evaluated as 0.58–0.68 mg kg^{− 1} diet based on WGR and GSH-Px activity in the hepatopancreas, and 1.07 mg Se kg^{− 1} diet was required to maximize whole body selenium content. Statement of relevance In this study, we evaluated the minimum dietary selenium requirement for juvenile oriental river prawn Macrobrachium nipponense. Dietary selenium deficiency and excess significantly reduced growth, antioxidant ability and immunity of prawn. Our results illustrate that supplementing appropriate amount of dietary selenium is necessary in prawn culturing. The minimum dietary selenium level for maximal growth and antioxidant ability of juvenile M. nipponense is recommended as 0.58–0.68 mg kg^{− 1} diet based on the analyses of WGR and GSH-Px activity, and 1.07 mg Se kg^{− 1} diet is required to maximize whole body selenium content. This research will facilitate to the development of practical diet for prawn.