Epsilon Archive for Student Projects

Abstract

The rapid growth of the aquaculture industry has brought increased attention to fish welfare, especially with rising demand for ethical and sustainable aquaculture practices. Traditional anaesthetics, like MS-222 (Tricaine), are effective but raise concerns related to fish welfare, environmental impact, and humane consumption due to their chemical nature. This study addresses these concerns by evaluating the efficacy of a novel herbal formulation combined with isoeugenol, a plant-derived anaesthetic, in promoting welfare outcomes for salmonids, specifically in rainbow trout and brown trout. The research involved a detailed assessment of the anaesthetic’s impact on welfare parameters, examining stress biomarkers (cortisol) and tissue integrity through histological analysis of gills. Preliminary trials compared induction times, recovery rates, isoeugenol dose responses, and sedation depth of the herbal-isoeugenol formulation against MS-222. High-performance liquid chromatography (HPLC) was employed to analyse skin-on-fillet tissue concentrations, providing data to determine safe withdrawal periods for human consumption of isoeugenol-treated fish. Results showed that MS-222 achieved faster induction than lower doses of isoeugenol, while higher isoeugenol concentrations improved induction times. Nutraceutical additions had minimal impact on recovery times and anaesthesia depth but were associated with increased structural changes in S. trutta gills and elevated cortisol levels at higher doses. HPLC analysis detected residual isoeugenol in tissues 48 hours post-exposure, indicating potential influence of nutraceuticals on retention. The findings suggest that the herbal formulation combined with isoeugenol could offer a more sustainable, welfare-friendly alternative to conventional anaesthetics, with potential benefits for reducing stress, supporting recovery, and enhancing overall fish health. However, it is essential for future research to further investigate and refine optimal dosing and formation impacts. This research provides valuable insights into humane and environmentally responsible aquaculture practices, aligning with consumer demand for ethically produced seafood.