Boosting growth, health, and productivity of Nile tilapia by supplementing Artemisia annua under tropical net cage farming conditions

The rapid global expansion of aquaculture demands innovative strategies to enhance productivity while safeguarding fish health under intensive rearing conditions. This study investigated the effects of dietary supplementation with an alcoholic extract of Artemisia annua (ae-Aa) on growth performance, physiological stress, immune responses, oxidative status, and tissue morphology of Nile tilapia ( Oreochromis niloticus ) cultured in a high-density net-cage system. A 2 × 2 factorial was applied, including two dietary treatments (supplemented, S; non-supplemented, NS) and two feeding periods (30 and 60 days), yielding four experimental groups (S-30, NS-30, S-60, NS-60). Compared with their respective controls, ae-Aa supplementation significantly enhanced survival and growth at both time points (P < 0.05), evidenced by greater weight gain and protein efficiency ratio and a reduced feed conversion ratio. Supplemented fish also showed increased intestinal villus thickness and hepatosomatic index (P < 0.05). Plasma cortisol concentrations were significantly lower in supplemented groups at both sampling periods (P < 0.05). Moreover, ae-Aa supplementation stimulated innate immune responses, reflected by elevated lysozyme activity, plasma protein level, and leukocyte respiratory burst (P < 0.05). Oxidative stress was notably mitigated in supplemented fish (P < 0.05), with reduced lipid peroxidation, enhanced catalase, glutathione peroxidase, and glutathione S-transferase activities, and decreased DNA damage observed at 60 days. In conclusion, dietary ae-Aa supplementation improved growth performance, immune competence, antioxidant capacity, and tissue integrity while alleviating physiological stress in Nile tilapia, supporting its application as a sustainable plant-based feed additive for intensive aquaculture systems. • Artemisia annua extract improves growth and survival rates of Nile tilapia farmed in net cages in tropical winter conditions. • Supplementation with Artemisia annua extract enhances feed conversion ratio and overall growth performance in Nile tilapia. • Nile tilapia supplemented with Artemisia annua extract exhibit reduced stress levels and enhanced immune function. • The antioxidant defense system is upregulated in Nile tilapia following Artemisia annua extract supplementation • Plant-based additives such as Artemisia annua represent sustainable alternatives to improve productivity in aquaculture.