Impacts of astaxanthin-enriched Paracoccus carotinifaciens on growth, immune responses, and reproduction performance of broodstock Nile tilapia during winter season

Abstract

The growth, immune response, and reproductive performance of broodstock of Nile tilapia (Oreochromis niloticus) under winter stress conditions were investigated the effects of supplementary diets with astaxanthin-enriched bacterium, Paracoccus carotinifaciens. Throughout an eight-week period in the winter season, male and female tilapia were fed with diets containing different levels of P. carotinifaciens dietary supplementation: 0 g/kg (T1; control), 5 g/kg (T2), 10 g/kg (T3), and 20 g/kg (T4). Subsequently, a four-week mating system was implemented during the winter stress period. The results revealed that there were no signi cant differences observed in growth, hematological indices, and blood chemical pro les among all treatment groups for both male and female tilapia. However, a signi cant increase in cholesterol content was noted in both male and female tilapia fed with the T4 diet (p<0.05). The total carotenoid content in the muscle was evaluated, and signi cantly higher values were found in both male and female tilapia that fed T4 supplementation (p<0.05). Moreover, immunological parameters such as myeloperoxidase and antioxidant parameters in the liver including superoxide dismutase activity and catalase enzyme activity showed signi cant increases in tilapia fed with the T4 diet. The impact of P. carotinifacienssupplementation on broodstock tilapia indicated a signi cant increase in spermatozoa concentration in males and increased egg production in females after consumption of the T4 diet (p<0.05). Thus, this study highlighted that the presence of astaxanthin-enriched bacterium P. carotinifaciensin the diet of broodstock Nile tilapia can lead to the accumulation of carotenoids in their muscle tissue, improvement in antioxidant status, enhancement of immune function, and potential enhancement of reproductive capabilities, even under overwintering conditions.