RT Journal Article T1 Evidence of gastrointestinal sensing and gut-brain communication in rainbow trout (Oncorhynchus mykiss) in response to the aqueous extract of fishmeal and its free amino acid fraction A1 Calo Rodríguez, Jessica A1 Soengas Fernández, José Luis A1 Pastor, Jose J. A1 Blanco Imperiali, Ayelén Melisa A1 Morais, Sofía K1 2401.13 Fisiología Animal K1 3105.02 Piscicultura AB Using rainbow trout (Oncorhynchus mykiss) as a model, we aimed to obtain information about the gastrointestinal tract (GIT) amino acid sensing capacity and hormone production along regions of the GIT, in response to proline (Pro), to a solution of free amino acids (FAA) mimicking the composition of a fishmeal (FM) aqueous extract (FM-FAA), or to the whole FM aqueous extract (FM-AQE). In addition, we evaluated central responses (in hypothalamus) in mechanisms regulating food intake, 2 h following intragastric administration of these treatments. The presence of Pro in the GIT elicited changes in amino acid sensing systems and in the production of GIT hormones, especially in the more proximal regions in parallel with an anorectic response in hypothalamus. The intragastric administration of FM-AQE induced increased production of the anorectic hormones peptide tyrosine-tyrosine (PYY) and cholecystokinin (CCK) that occurred 20 min post-treatment in the proximal and middle intestine of this treatment. These changes occurred in parallel with an anorectic response in the hypothalamus 2 h post-treatment. The treatment with FM-FAA elicited a comparable anorectic response in the hypothalamus at 2 h post-treatment, which was associated however with a more complex response in the GIT. This included a comparable increased production of the anorectic hormones PYY and CCK in the proximal and middle intestine, but also a decreased production of the orexigenic hormone ghrelin (GHRL) in the stomach, 20 min after FM-FAA administration. These effects were also accompanied by some changes in parameters related to amino acid sensing systems mediated by receptors, which were not observed in the FM-AQE treatment. Overall, results indicate that all treatments elicited a response in elements of gut sensing mechanisms and gut-brain axis, despite important differences in the specific genes (likely having different substrate specificities), GIT areas and times in which responses were observed PB Aquaculture SN 00448486 YR 2023 FD 2023-03-30 LK http://hdl.handle.net/11093/4413 UL http://hdl.handle.net/11093/4413 LA eng NO Aquaculture, 567, 739264 (2023) NO Xunta de Galicia | Ref. ED431B 2022/01 DS Investigo RD 03-dic-2024