Evaluation of immune‐response biomarkers in gilthead seabream fed with novel feed formulations

Trabajo presentado en el 6th International Symposium on Genomics in Aquaculture, celebrado en Granada (España) del 05 al 07 de mayo de 2021.The aquaculture industry continues to grow faster than any other food production sector. This growth was also convoyed by increased consumer environmental awareness and knowledge. Hence, the necessity to make aquaculture as sustainable as possible became more obvious day-byday. This work is part of GAIN project and aims to rise solutions to this need. For that four diets were formulated for in gilthead seabream (Sparus aurata) rich in animal protein (PAP), without animal protein (NOPAP) and a combination of diverse emerging ingredients (MIX), against a control diet. The selected ingredients were defined based on circularity principles, maximizing resource efficiency. The immune parameters analyzed (bactericidal, IgM, protease and antiprotease activity) suggest that fish fed with NOPAP diet showed a slight stimulation of innate immunity. This is corroborated by the head kidney gene expression results, which also showed that il-8 was up-regulated in NOPAP, PAP and MIX groups. The PAP group presented a strong proinflammatory profile, evidenced not only by the up regulation of il-8 but also other cytokines (il1β, tnf-α), chemokines (ck8) and chemokine receptors (ccr3). The same pattern was found for the T-cell markers cd3x, cd4-full and cd8a, whereas the expression of the mucosal igt-m was consistently down-regulated. Both MIX- and NOPAP-fed fish showed a more attenuated response, since compared to the control diet, only a reduced number of genes was differentially expressed, il8 in NOPAP-fed fish, and il-8, il-1β and ck8 in the MIX diet group. These results support the hypothesis that these new formulations are viable options for seabream feed, in particular the NOPAP