Browsing by Author "Lopes, Tiago da Santa"
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- Can lysine and branched-chain amino acids improve lumpfish health and stress resilience?Publication . Lopes, Tiago da Santa; Costas, Benjamin; Ramos-Pinto, Lourenço; Pimentel, Christopher; Pinto-Cunha, Francisco; Reynolds, Patrick; Imsland, Albert K. D.; Aragão, Cláudia; Fernandes, Jorge M. O.The expansion of lumpfish use as a cleaner fish has recently come to a halt, in part due to the concerns around their welfare. While refining handling procedures and operational standards is necessary, improving aquafeeds has the potential to alleviate the burden caused by chronic stress. This study examined the influence of different inclusions of dietary branched-chain amino acids (BCAAs) and lysine (Lys) on lumpfish health, immunity, stress response, growth and plasma amino acid profiles for 10 weeks. Stress and metabolic biomarkers (cortisol, lactate, glucose, triglycerides) showed modest but measurable alterations, such as lower triglycerides and higher glucose in fish fed the diet with limiting Lys and BCAAs. Metabolic differences were also visible from plasma amino acid profiles. Limiting Lys and BCAAs in diets seems to increase the glucogenic activity in stressed fish, increasing glucogenic amino acid levels in plasma. Diets with increased Lys and BCAAs levels increased antiprotease activity and lowered GABA plasma concentrations. These findings suggest that Lys- and BCAAs-enriched diets might provide relevant nutritional support, which allows the organism to adapt to a mild chronic stress. Immunonutrition can prove to be an effective strategy to ameliorate welfare in the face of chronic stress.
- Lumpfish physiological response to chronic stressPublication . Lopes, Tiago da Santa; Costas, Benjamin; Ramos-Pinto, Lourenço; Reynolds, Patrick; Imsland, Albert K. D.; Fernandes, Jorge M. O.; Aragão, CláudiaIn this study, we explored the effects of chronic stress on lumpfish (Cyclopterus lumpus) physiological, immune response, health, and plasma free amino acids. 3 groups of lumpfish were exposed to 1-minute air exposure. 1 group was exposed to stress once per week, a second group exposed 2 times per week, and a third group exposed 4 times per week. The present study revealed significant alterations in immunity and increased nutritional demands, particularly the branched chain amino acids and lysine. Cortisol levels fluctuated, with significantly higher levels halfway through the experiment on the groups that were stressed more often. Though, by the end of the experiment, there were no significant differences in cortisol levels between groups. Regardless of stress exposure, cataract developed in virtually all sampled fish, pointing toward a potential dietary imbalance. A transient immunomodulation of stress was visible. While in early stages stress had an immune enhancing effect, as seen by the increase in plasma nitric oxide and peroxidase in the group most frequently exposed to stress, these differences were not apparent by the end of the experiment. Additionally, the worst health condition was found in this group. Our results underscore the complex interplay between stress, immunity and nutrition, highlighting the need for tailored dietary strategies and improved rearing practices.