Melhorando o bem-estar dos peixes na aquacultura com analgésicos naturais

The PAINLESSFISH project aims to investigate the potential analgesic effects of natural compounds, namely thymol, menthol, 24-epibrassinolide (24-EPI) and oleanolic acid (OA), in fish subjected to a painful stimulus. The ultimate goal is its application in aquaculture during potentially painful procedures, thus promoting the well-being of the fish while promoting sustainability and aquaculture financial return. For this, several objectives will be achieved during the course of the project. With the first task, we aim to find the natural compound and its concentration with the greatest analgesic efficacy. For this purpose, the compounds thymol, menthol, 24-EPI and OA will be screened based on their potential analgesic properties and absence of toxic effects. The compounds will be tested in zebrafish larvae under painful WW stimulation. Zebrafish larvae exposed to the WW stimulus but treated with effective analgesics are expected to behave at control levels and not show aversion to warm temperature. The compound and its concentration with the greatest analgesic efficacy will be used in subsequent tasks. The second task aims to evaluate the physiologic and biochemical indicators of fish welfare under WW stimulus and analgesic inhibition, and to investigate the mechanisms of action of these potential natural analgesics in the zebrafish larvae used in the first task. At the end of the second task, we expect to elucidate the cellular and biochemical changes that occur during the noxious stimuli with or without the presence of natural analgesics. In the third task, we intend to evaluate the analgesic properties of the most promising natural compound and its concentration, chosen in the first task, in adult zebrafish subjected to the WW stimulus. We also intend to find the best analgesic protocol, and to this end we will test whether pre-treatment or post-treatment with the natural analgesic will improve its efficacy. At the end of this task, we expect to confirm the analgesic efficacy of the chosen compound in the adult zebrafish and establish the best analgesic protocol. The antinociception efficacy of the chosen protocol will then be tested in adult rainbow trout under the WW stimulus in the fourth task, since rainbow trout is one of the most important fish species in aquaculture and also a representative species of the salmonid family. Another objective of the fourth task is to effectively deliver the analgesic compound through mucoadhesive nanoparticles (MANPs). MANPs adhere to the mucosal surfaces of fish, allowing the concentration of the compound to be used to be reduced, while also allowing its controlled release. At the end of this task, we expect to fulfill the objective of confirming the analgesic efficacy of the chosen compound and establishing the analgesic protocol with that natural compound to be implemented in aquaculture when potentially painful procedures are necessary. If successful, the results regarding the effectiveness of the natural compound and its respective analgesic protocol with potential application in aquaculture will be subject to patent pre-registration.