Combined transcriptomic and metabolomic analyses revealed the mechanisms by which preferential baits regulate feeding and appetite responses in Neptunea arthritica cumingii Crosse

Neptunea arthritica cumingii Crosse is a large carnivorous marine snail with high economic value and aquaculture potential in the northern waters of China. Due to its low feeding response to existing feeds and other limiting factors, large-scale artificial cultivation of this species remains unachieved. To address this limitation, we used behavioral observation to compare this snail’s preferences for five different baits, and we also analyzed the biochemical composition of the baits. We also conducted transcriptomic and metabolomic analyses of the snail’s water tubes and olfactory organs using RNA-sequencing and liquid chromatography tandem mass spectrometry to identify genes and metabolites associated with feeding and fasting states. The results showed significant differences in feeding preferences among the five baits, with the highest frequency observed for Ezo scallops ( Mizuhopecten yessoensis ) and the lowest for Korean rockfish ( Sebastes schlegelii ). Comparative analysis of the bait compositions revealed that L-glycine and L-glutamic acid might be key food attractants. We found that the differentially expressed genes and differential metabolites in the snails were enriched in nutrient-related pathways, including neuroactive ligand-receptor interactions, the phosphoinositide 3-kinase–protein kinase B signaling pathway, and the oxytocin signaling pathway. After feeding on M. yessoensis , differentially expressed genes were linked to appetite stimulation, increased feeding rate, and biosynthesis of phenylalanine, tyrosine, and tryptophan. In summary, we identified the preferred bait and potential food attractants for N. cumingii , thereby establishing a theoretical basis for understanding its feeding regulation mechanism and developing artificial compound feeds, with both theoretical significance and practical application value.