Schizochytrium sp. as a promising Artemia tibetiana nauplii fortifier for yellow drum (Nibea albiflora) larviculture

This study evaluated the efficacy of enriching Artemia tibetiana nauplii with Schizochytrium sp. to improve nutritional quality and its impact on yellow drum (Nibea albiflora) larvae, focusing on growth, weaning performance, and stress resistance. Optimal enrichment conditions were determined as 50 nauplii/mL seawater with 40 g Schizochytrium sp. per ton for 12 hours, significantly increasing DHA levels in nauplii (P < 0.05), without affecting survival or size. A 10-day feeding trial with 12-day post-hatch larvae demonstrated that the treatment group (SCH, fed Schizochytrium sp.-enriched A. tibetiana) exhibited superior growth performance compared to the control group (CON, fed unenriched A. tibetiana). This enhancement was attributed to improved intestinal digestive functions, characterized by significant increases in muscular fold height, perimeter ratio, microvilli length, and microvilli density (P < 0.05). Liver lipid accumulation in the SCH group was significantly reduced, with decreased lipid droplet proportion and area (P < 0.05), supported by RNA-seq evidence of downregulated lipid synthesis and upregulated fatty acid catabolism genes in intestinal and liver tissues. In the weaning phase, SCH larvae maintained significantly higher growth rates over 5 days (P < 0.05) and showed greater desiccation stress resistance, linked to upregulated nonspecific immune-related gene expression. Collectively, Schizochytrium-enriched A. tibetiana nauplii improves larval growth, liver lipid metabolism, and stress resilience, highlighting a promising strategy for enhancing marine larviculture practices.