The current study examined how feeding gilthead seabream with copepod Acartia tonsa impacts the ontogeny of the digestive system and the skeleton. Six cylindroconical tanks of 100 L each were stocked with 10,000 seabream eggs. In three tanks, Acartia tonsa was also administrated from 3 to 17 days after hatching (DAH) and Brachionus sp. until 25 DAH—end of the experiment (Copepods group), while in the other three tanks, only Brachionus sp. (Control group). On days 16 to 20 DAH, the fish in all tanks began to be fed with Artemia nauplii, and enriched Artemia metanauplii were used from 18 to 25 DAH. Copepod‐fed larvae exhibited significantly greater intestinal villi length and surface area, higher hepatic lipid accumulation, and earlier appearance of goblet cells compared to the control ( p < 0.05). Skeletal ontogeny was improved, since all the examined structures appeared and completed earlier in the Copepods group, and the cleithrum was the only fully calcified structure, observed exclusively in copepod‐fed fish. Moreover, skeletal deformities were significantly reduced, and swim bladder inflation success was higher ( p < 0.05). Although scoliosis was observed in both groups on 7 DAH and most likely originated from the notochord rather than the vertebral column, by the end of the experiment, its incidence was much lower in the Copepods group, indicating that copepod feeding might have contributed to recovery from early deformities. Copepod‐fed fish showed higher total length at the end of the trial, demonstrating that the benefits of copepod inclusion persisted beyond the feeding period. Overall, larvae reared with copepods under these conditions (3–17 DAH) showed superior digestive, skeletal, and growth performance, supporting the inclusion of A. tonsa in early feeding protocols to improve larval quality and reduce deformities, which could improve the commercial seabream production.
Loufi et al. (Thu,) studied this question.