How does weaning anticipation affect gilthead seabream (Sparus aurata) larvae digestive capacity, growth and survival?

The gilthead seabream is one of the most important Mediterranean aquaculture fish species. It is important to study the ability of fish larvae to grow and survive with respect to their feed. The attempt to shorten the period consumed by fish larvae depending on live food would reduce the production cost. Hence, the current study aimed to evaluate the effect of anticipating weaning as early as 27 days old on fish digestive capacity, intestinal histomorphology, growth, and survival. Fish larvae were weaned at 27 (W27), 35 (W35), and 43 (W43) days after hatching (DAH), with a co-feeding of 5 days. Samples were collected at the weaning day (T0), 1 week (T1), and 4 weeks after the weaning (T4) to determine their digestive enzymes. Sea bream larvae weaned at different age stages exhibited similar growth and survival rates, aligned with normal intestinal morphology. Regardless of their weaning age, the experimental groups showed an identical pattern of digestive enzyme activities variation. W27 fish were able to recover, and at 70 DAH digestive enzymes activities were similar among experimental groups. These results indicate that fish age/size influences the magnitude of digestive enzyme activities. Weaning gilthead sea bream at 27 DAH can have a high economic advantage on hatcheries by reducing the production and labor costs of live feeds production.