Global farmed shrimp production is projected to reach 6 million tons in 2025, yet hatchery inefficiencies, particularly in larval feeding protocols, limit survival and sustainability. Artemia remains the primary live feed for Litopenaeus vannamei larvae, but practices vary widely from 100% live instar I nauplii to decapsulated cysts or unstandardized mixtures often based on convenience rather than evidence. The optimal life stage and form for maximizing larval growth, immunity, and microbial stability remain unclear despite substantial global research investment.
We conducted a controlled feeding trial with four dietary treatments: T1 (100% live instar I nauplii), T2 (100% decapsulated cysts), T3 (60% live:40% decap), and T4 (40% live:60% decap). Larvae were assessed for proximate composition, ten essential amino acids, and essential fatty acids (18:2 n-6, 18:3 n-3, 20:5 n-3, 22:6 n-3, 20:4 n-6), as well as immune gene expression, including HSP60, HSP70, HSP90, penaeidins, crustins, prophenoloxidase, lysozyme, and lectins. Hepatopancreas histology and postlarval gut microbiome profiles were also evaluated. Microbiome profiling was performed using total DNA quantification (Total Genome Copies × 4.64 × 10⁶ bp × 660 g/mol ÷ 6.022 × 10²³), full-length 16S rRNA sequencing, rarefaction analysis to ensure coverage, and Linear Discriminant Analysis Effect Size (LEfSe) to identify discriminant taxa. All measured parameters were statistically analyzed using the MIXED model, with significance set at P ≤ 0.05.
Results indicated clear treatment-dependent effects. T4 (40% live:60% decap) produced the most stable microbiome, enriched in beneficial Erythrobacteraceae, and elicited moderate immune activation. T1 promoted high diversity dominated by Proteobacteria, T2 reduced diversity while enriching opportunistic Enterobacteriaceae, and T3 generated unstable intermediate profiles. Immune responses, including heat shock proteins and effector molecules, mirrored these microbial patterns. Overall study demonstrated that a 40:60 live:decapsulated Artemia feeding strategy optimizes larval nutrition, microbiome stability, and immune resilience, scalable protocol for global shrimp hatcheries to enhance survival, disease resistance, and sustainability.