Enhancing growth, pigmentation, and health in Penaeus vannamei through zeaxanthin supplementation

Carotenoids are essential dietary components in aquaculture, widely used to enhance pigmentation, improve stress tolerance, and boost immune responses in aquatic animals. An 8-week feeding trial was conducted to evaluate the effects of varying dietary levels of zeaxanthin (Zea) on the growth performance, carotenoid composition, antioxidant capacity, intestinal microbiota, biochemical parameters, and immune-physiological responses of Penaeus vannamei. A total of 600 juveniles (initial weight: 1.21 ± 0.12 g) were fed with five iso‑nitrogenous and isolipidic experimental diets containing incremental levels of Zea (0, 50, 100, 200, and 400 mg/kg diet). The results showed that dietary Zea supplementation significantly improved carotenoid deposition in shrimp tissues. Additionally, changes in carotenoid levels within the shrimp body demonstrated significant positive correlations (P < 0.05) with growth performance indicators, survival, feed conversion ratio, DHA deposition, hemato-immunological enzymes (alkaline phosphatase, lysozyme, acid phosphatase), antioxidant capacities (total antioxidant capacity and peroxidase), digestive enzymes activities, hypoxia tolerance response (LT₅₀), and redness and yellowness parameters (a^⁎and b^⁎). While dietary Zea did not affect the total bacterial load, it significantly influenced intestinal microbiota diversity indices (Simpson, Shannon, and Chao) and relative abundance of dominant phyla, such as Proteobacteria. Furthermore, a comprehensive evaluation using Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), combined with broken-line regression analysis, revealed that dietary Zea supplementation between 110.5 and 187.4 mg/kg diet resulted in distributed improvements across multiple parameters, including growth, antioxidant capacity, stress tolerance, enzyme activity, digestion, and body coloration. These findings highlight the potential of Zea as an alternative to traditional carotenoids in aquaculture. This study provides valuable insights into optimizing shrimp feed formulation, enhancing sustainability, and reducing production costs while maintaining high product quality.