de Fátima Pereira de Faria Camila, de Andrade Beatriz Ullian, Urbinati Elisabeth Criscuolo
São Paulo State University (UNESP), Aquaculture Center of UNESP, Jaboticabal, Sao Paulo, Brazil.
School of Agricultural and Veterinary Sciences, São Paulo State University (UNESP), Jaboticabal, Sao Paulo, Brazil.
Fish Physiol Biochem. 2025 Jan 14;51(1):9. doi: 10.1007/s10695-024-01445-z.
This study examined the energy-dependent physiological responses, including stress, innate immune, and antioxidant systems, as well as indicators of energy mobilization, in pacu (Piaractus mesopotamicus) exposed to intermittent cold, aiming to assess the correlations between these responses. The fish were acclimated to 28 °C, divided into two groups, a control group maintained at 28 °C, and another exposed to 16 °C for two 24 h periods with a 5-day interval between them. The fish were sampled at six time points: baseline (after acclimatization to 28 °C), 24 h after the 1st exposure to 16 °C, after 5 days of recovery at 28 °C, 24 h after the 2nd exposure to 16 °C, and after 24 and 48 h of recovery at 28 °C. The reduction in temperature activated the stress response, the innate immune system, and the antioxidative system as well as mobilized lipids from the visceral stores and preserved the circulating levels of triglycerides. Intermittent exposure of fish to cold increased plasma cortisol after both exposures, activated leukocyte respiratory activity after the 2nd exposure, and triggered the compensatory lysozyme response after temperature recovery in both cold exposures in addition to increasing the number of circulating monocytes and granulocytes. The activity of the enzymes catalase (CAT) and superoxide dismutase (SOD) increased after the 1st and 2nd cold exposures, respectively. Glutathione peroxidase (GPx) activity increased after the 2nd exposure compared to the control. The subtropical fish pacu was sensitive to intermittent cold exposure and was able to display protective physiological responses.
本研究检测了暴露于间歇性低温环境下的淡水白鲳（Piaractus mesopotamicus）的能量依赖性生理反应，包括应激、先天免疫和抗氧化系统，以及能量动员指标，旨在评估这些反应之间的相关性。将鱼适应于28°C，分为两组，一组为对照组，维持在28°C，另一组在16°C下暴露两个24小时时间段，中间间隔5天。在六个时间点对鱼进行采样：基线（适应28°C后）、第一次暴露于16°C后24小时、在28°C恢复5天后、第二次暴露于16°C后24小时，以及在28°C恢复24小时和48小时后。温度降低激活了应激反应、先天免疫系统和抗氧化系统，同时动员了内脏储存的脂质，并维持了甘油三酯的循环水平。鱼间歇性暴露于低温后，两次暴露后血浆皮质醇均升高，第二次暴露后激活了白细胞呼吸活性，除了增加循环单核细胞和粒细胞数量外，在两次低温暴露温度恢复后均引发了溶菌酶的代偿性反应。过氧化氢酶（CAT）和超氧化物歧化酶（SOD）的活性分别在第一次和第二次低温暴露后增加。与对照组相比，第二次暴露后谷胱甘肽过氧化物酶（GPx）活性增加。亚热带鱼类淡水白鲳对间歇性低温暴露敏感，并能够表现出保护性生理反应。
