Gilthead Seabream Larvae Growth and Survival Using New Co‐Feeding Regimes With Early Microdiet Application

To be economically viable and improve welfare, innovative feeding regimes are imperative for achieving high growth and survival rates in gilthead seabream larval production. In a gilthead seabream ( Sparus aurata ) larvae trial, we compared four novel feeding regimes to the standard diet (Std‐Art), which included consecutive feeding of Brachionus plicatilis (Rot) and Artemia salina (Art) from 4 days post‐hatching (dph) until weaning at 32 dph, followed by microdiet (MD) until 56 dph. All newly formulated feeding regimes included MD mostly from first‐feeding, with variations in live feeds provided. The first regime included initial consecutive feeding of Acartia tonsa nauplii (Cop) and then Artemia until weaning at 26 dph (MDe‐Cop‐Art). The second regime involved rotifer feeding until 20 dph (MDe‐Rot), while the third provided A. tonsa until 20 dph (MDe‐Cop). The fourth regime featured consecutive feeding of two copepods species, the regularly used A. tonsa and a newly tested tropical species, Apocyclops panamensis (from nauplii to copepodite) until 20 dph, introducing MD at 18 dph (MDa‐2Cop). The MDe‐Cop‐Art regime substantially outperformed all other regimes in survival rate (37.5% ± 2.7% vs. 21.1% ± 2.7% of Std‐Art) and total biomass production per tank (69 ± 7 g vs. 16 ± 7 g of Std‐Art). This highlights the advantage of feeding copepods over rotifers and emphasises the importance of a short Artemia inclusion, potentially improving feeding activity, digestion and assimilation. Co‐feeding live feed with MD from first‐feeding was found to enhance growth and survival, indicating the progressive adaptation of larvae to the physical and biochemical characteristics of the MD. This adaptation likely promoted earlier maturation of the digestive system and improved nutrient uptake and utilisation. Considering the overall growth and survival performance, the incorporation of MD from first‐feeding, coupled with A. tonsa and followed by a short Artemia feeding is highly recommended for gilthead seabream larvae commercial rearing.