Effects of replacement of inorganic trace elements by organic trace elements in alternative diets of Tenebrio molitor on growth performance, antioxidant capacity, immunity and intestinal flora of Litopenaeus vannamei

This study evaluated the effects of replacing inorganic trace elements with organic forms in T enebrio molitor -based diets on the growth performance, antioxidant capacity, immune response, and intestinal microbiota of Pacific white shrimp ( Litopenaeus vannamei ). A total of 480 juvenile shrimp (initial body weight 0.26 ± 0.01 g) were randomly assigned to four dietary treatments with three replicates per treatment for a 10-week feeding trial. A fishmeal-based diet supplemented with inorganic trace elements served as the control. In the negative control, 40 % of fishmeal was replaced with T. molitor . Based on this diet, inorganic iron, manganese, and zinc were replaced with 40 % or 60 % organic forms. Shrimp fed the diet containing 60 % organic trace elements showed significantly lower final body weight, weight gain rate, and specific growth rate, as well as a higher feed conversion ratio, compared with the 40 % replacement group. Although fishmeal replacement with T. molitor reduced antioxidant capacity, supplementation with organic trace elements significantly increased the activities of superoxide dismutase, catalase, and glutathione peroxidase. The activities of acid phosphatase and alkaline phosphatase and the expression of immune-related genes were significantly enhanced in shrimp fed the diet containing 40 % organic trace elements. In addition, organic trace element supplementation partially improved intestinal microbiota composition by reducing potential pathogenic bacteria. In conclusion, the 40 % replacement of inorganic iron, manganese, and zinc with organic forms was identified as the optimal proportion, as it enhanced antioxidant and immune responses without compromising growth performance in L. vannamei . • Optimal 40 % organic replacement enhances immune response and antioxidant capacity in Pacific white shrimp. • Excessive 60 % organic substitution inhibits growth but improves intestinal microbiota diversity. • A 40 % organic substitution strategy optimizes health and supports sustainable aquafeeds.