Transition from endogenous to exogenous feeding in hatchery-cultured European eel larvae

The transition from endogenous to exogenous feeding is critical during fish early life, where appropriate feed availability and timing of initiation influence survival. For European eel (Anguilla anguilla), establishing first culture at a pioneering state, successful production larvae has recently enabled experiments. In the present study, three diets potential benefits yolk-sac stage were explored, including molecular analyses genes involved in digestive functions growth. Three consecutive trials performed using hatchery produced offspring. Feeding regimes 1 3, expression npy cck (appetite regulation) was higher, while pomca (food intake) lower non-prefed larvae, indicating increased fasting higher starvation risk. contrast, regime 2 led highest survival ever registered for i.e. 20% 20 dph, spite that prefeeding resulted reduced rate stage. This associated with initial hsp90 (stress/repair) upregulation receiving prefeeding, however, subsequent downregulation feeding. Notably, growth related gh prefed prefeeding. Likewise, as well try, tgl, amyl2a (digestion) upregulation, providing evidence beneficial maturation gut functionalities. Essentially, demonstrated continuous growth, appetite digestion genes, which combination suggest dietary requirements partially met. Moreover, 2, tgl expressed level than control, might be advantageous observed mortality, but further research needed, application.