Astaxanthin is a carotenoid known for its antioxidant properties and its contribution to the performance of aquatic organisms, especially during early development. However, its low stability and bioavailability limit its effectiveness in conventional forms. Nanotechnology offers a promising approach to enhance the absorption and protection of this molecule, improving its use in larviculture. This study evaluated the effects of different concentrations of astaxanthin nanocapsules on the growth of Penaeus vannamei larvae over a 20-day culture period, from the nauplius stage to postlarva 10. Water quality parameters—temperature, dissolved oxygen, pH, salinity, ammonia, nitrite, nitrate, phosphate, alkalinity, and CO₂—were monitored to maintain suitable conditions. Four nano-astaxanthin concentrations were tested, each with four replicates: 0 mg/L (control), 0.9375 mg/L, 1.875 mg/L, and 3.75 mg/L. Larvae were reared under controlled conditions, received stage-appropriate feeding, and nanocapsules were applied directly to the water twice daily. Growth was assessed at the end of the trial by measuring postlarval total length to compare performance across treatments.
Results showed a clear dose-dependent response of Penaeus vannamei larvae to nano-astaxanthin. The control group reached ~10 mm, while low (0.9375 mg/L) and intermediate (1.875 mg/L) concentrations resulted in reduced growth (8.8 and 8 mm, respectively), with the intermediate dose showing the highest variability. In contrast, the highest concentration (3.75 mg/L) significantly increased larval length (~13 mm), with consistent performance across individuals. Survival was also higher in treatments with astaxanthin addition (~50%) compared to the control (33%).
These findings indicate that only higher doses effectively enhance PL10 growth after 20 days. Nano-astaxanthin therefore shows promise as a nutritional supplement in larviculture, though further studies on survival, immunity, long-term effects, and cost-benefit are needed for commercial application.