Metabolomic dynamics during egg development and hatching in the invasive apple snail Pomacea canaliculata

The highly invasive freshwater snail Pomacea canaliculata is distinguished by exceptional fecundity, making the egg stage a critical focus for understanding its reproductive biology. Characterizing the metabolic dynamics of this period can reveal the key metabolites and pathways that sustain embryonic development, hatching, and the embryo-to-juvenile transition, and thus illuminate the metabolic basis of the species' reproductive capacity and ecological success. Using non-targeted metabolomics, this study profiled dynamic metabolic changes across egg development and hatching in P. canaliculata, spanning three embryonic stages and one post-hatching stage: Stage I (first day post-oviposition), Stage II (head-foot differentiation), Stage III (formation of major internal and external organs), and the 1-day post-hatching juvenile stage (1-dph). Amino acids and their derivatives, including phenylalanine, serine, and isoleucine, were the most abundant class of differential metabolites across all stages, implicating them in metabolic changes potentially associated with early nervous system development during embryogenesis and in the physiological remodeling associated with hatching and juvenile emergence. Pathway enrichment analysis highlighted purine and pyrimidine metabolism, ABC transporters, and core metabolic networks as particularly active, reflecting the demands of cell division and differentiation, energy provision, immune regulation, and intercellular signaling. Carotenoids, including astaxanthin and β-carotene derivatives, were also detected and are likely to contribute to antioxidant defense and lipid metabolic regulation. The progressive color changes of the egg masses during incubation appear to arise primarily from the dynamic remodeling of perivitelline carotenoid-protein complexes rather than from fluctuations in free carotenoid levels. Together, these results define a metabolic framework for egg development and the embryo-to-juvenile transition in P. canaliculata, with broader implications for the developmental biology of oviparous freshwater gastropods.