Dietary astaxanthin supplementation improves semen quality and systemic physiological health in pubertal male Nile tilapia (Oreochromis niloticus)

Abstract

This study evaluated the effects of dietary astaxanthin on sperm quality and physiological indicators of pubertal male Nile tilapia, Oreochromis niloticus (Linnaeus, 1758). Fish (32.42 ± 0.51 g) were allocated to 16 tanks in recirculating aquaculture system (220 L; 5 fish tank −1 ), with four replicate tanks per dietary treatment, and fed for 45 days with diets containing 0, 50, 100, and 150 mg kg −1 astaxanthin derived from microalgae Haematococcus pluvialis . Astaxanthin supplementation markedly improved seminal traits: males receiving 50–150 mg kg −1 exhibited significantly greater semen volume, sperm concentration and motility, and a higher proportion of morphologically normal sperm than controls ( P < 0.05). Semen from supplemented groups also showed reduced catalase activity and malondialdehyde levels ( P < 0.05), indicating lower oxidative stress. Growth performance and survival did not differ among treatments ( P > 0.05). Hematologically, astaxanthin, particularly at 100–150 mg kg −1 , increased lymphocyte proportions while decreasing circulating neutrophils, monocytes, and thrombocytes ( P < 0.05). Serum biochemistry indicated changes in metabolic status at 100–150 mg kg −1 , with reduced glucose, total cholesterol, triglycerides, alanine aminotransferase, and aspartate aminotransferase, and elevated total protein, albumin, and globulin ( P < 0.05). Collectively, these findings indicate that dietary astaxanthin, particularly at 100–150 mg kg −1 , supports semen quality and physiological status in pubertal male Nile tilapia without compromising growth.

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