Journal of Fisheries 2008-5729 74 3 2021 09 23 Effects of dietary supplementation of astaxanthin on antioxidant status and digestive enzyme activities of the oriental river prawn (Macrobrachium nipponense) Effects of dietary supplementation of astaxanthin on antioxidant status and digestive enzyme activities of the oriental river prawn (Macrobrachium nipponense) 363 374 83318 10.22059/jfisheries.2021.323858.1250 FA Mohammad Ettefaghdoost Ph. D student, Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran Hamid Noverian Associate professor, Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran Mir Masoud Sajjadi Professor, Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran Bahram Falahatkar Professor, Fisheries Department, Faculty of Natural Resources, University of Guilan, Sowmeh Sara, Guilan, Iran Journal Article 2021 05 15 Astaxanthin pigment is one of the most important carotenoids in terms of antioxidant properties, and an important micronutrient in the aquatics diet due to desirable effect on antioxidant activity, immunity functions, and feed efficiency. This study was conducted to evaluate the effects of astaxanthin pigment on antioxidant activity, and digestive enzymes of the oriental river prawn (<em>Macrobrachium</em> <em>nipponense</em>). In the present experiment, two hundred and twenty-five prawns with mean weight of 1.40±0.05 g were fed by five formulated diets containing different astaxanthin levels, zero (control), 50, 100, 150 and 200 mg per kg for 56 days. At the end of the culture period, the hepatopancreas, and intestine samples of the studied prawns were collected then antioxidant parameters, and digestive enzymes of the samples were evaluated by experimental kits, and spectrophotometric method.<strong> </strong>The results of the study showed that total antioxidant capacity increased significantly compared to control treatment, while superoxide dismutase, catalase, and malondialdehyde decreased significantly in diets containing astaxanthin treatments (p < 0.05). However, the antioxidant activity of glutathione peroxidase was not affected by different dietary astaxanthin levels (P>0.05). Digestive enzymes were affected by different astaxanthin levels, and with increasing dietary astaxanthin, digestive enzymes increased significantly (p < 0.05). Finally, the results of this study showed that increasing dietary astaxanthin levels improved the activity of antioxidant parameters, and digestive enzymes of the oriental river prawn, and suggests that diet containing 150 mg/kg of this pigment to improve the mentioned parameters of this prawn. <br />n. Astaxanthin pigment is one of the most important carotenoids in terms of antioxidant properties, and an important micronutrient in the aquatics diet due to desirable effect on antioxidant activity, immunity functions, and feed efficiency. This study was conducted to evaluate the effects of astaxanthin pigment on antioxidant activity, and digestive enzymes of the oriental river prawn (<em>Macrobrachium</em> <em>nipponense</em>). In the present experiment, two hundred and twenty-five prawns with mean weight of 1.40±0.05 g were fed by five formulated diets containing different astaxanthin levels, zero (control), 50, 100, 150 and 200 mg per kg for 56 days. At the end of the culture period, the hepatopancreas, and intestine samples of the studied prawns were collected then antioxidant parameters, and digestive enzymes of the samples were evaluated by experimental kits, and spectrophotometric method.<strong> </strong>The results of the study showed that total antioxidant capacity increased significantly compared to control treatment, while superoxide dismutase, catalase, and malondialdehyde decreased significantly in diets containing astaxanthin treatments (p < 0.05). However, the antioxidant activity of glutathione peroxidase was not affected by different dietary astaxanthin levels (P>0.05). Digestive enzymes were affected by different astaxanthin levels, and with increasing dietary astaxanthin, digestive enzymes increased significantly (p < 0.05). Finally, the results of this study showed that increasing dietary astaxanthin levels improved the activity of antioxidant parameters, and digestive enzymes of the oriental river prawn, and suggests that diet containing 150 mg/kg of this pigment to improve the mentioned parameters of this prawn. <br />n. https://jfisheries.ut.ac.ir/article_83318_5a6645b46e504e2dfc6492e135375aa0.pdf