Different dietary compositions shape reproductive physiology in Litopenaeus vannamei broodstock

Abstract Maintaining the reproductive performance of Litopenaeus vannamei broodstock toward the end of the breeding season remains a major challenge for commercial hatcheries, primarily due to physiological exhaustion. This study evaluated whether diversified dietary formulations could extend the breeding period and enhance larval quality. Broodstock (males: 50 ± 2 g; females: 69 ± 5 g) were allocated to four dietary treatments comprising worms ( Nereis spp., ragworm), squid ( Loligo forbesii ), and mussels ( Mytilus galloprovincialis ). Group 1: 80% worms and 20% squid; Group 2: 80% worms and 20% mussels; Group 3: 50% worms, 25% mussels, and 25% squid; and Group 4: equal proportions (25% each) of worms, mussels, squid, and chicken liver. Over a 30-day trial, reproductive indices (HSI, GSI, OMI), hemolymph biochemistry, hepatopancreatic antioxidant status, and the expression of key maturation-related genes ( vih , vtg , iag , igfbp1 ) were assessed, alongside histological examination of the hepatopancreas and gonads. Group 3 exhibited the highest reproductive efficiency, producing significantly greater egg output and larval yield compared with the worm-dominated control (Group 1). Molecular analyses showed a pronounced downregulation of vitellogenesis-inhibiting hormone ( vih ) in the eyestalks, accompanied by upregulation of vitellogenin ( vtg ) in the hepatopancreas of Groups 3 and 4. In males, expression of the insulin-like androgenic gland hormone ( iag ) peaked in Group 4, corresponding with enhanced histological structure of the vas deferens. Group 4 also exhibited enhanced hepatopancreatic antioxidant status, characterized by increased superoxide dismutase activity and reduced lipid peroxidation. Histological observations showed that diversified diets promoted healthy hepatopancreatic structure and sustained vitellogenic progression in the ovaries. Overall, reducing reliance on polychaetes and incorporating a balanced mix of mussels, squid, and chicken liver provides an effective nutritional strategy to rejuvenate aging broodstock. These findings offer a practical nutritional approach for hatcheries to enhance seed production and potentially prolong broodstock productivity, with the observed reproductive responses associated with changes in neuroendocrine-related marker gene expression.