Large-mouth bass originally lived in rivers and lakes and now is often raised in recirculating aquaculture systems (RAS). However, the shortcoming of RAS is that there is very limited space for swimming fish in a high-density culture environment, thus leading to a lack of exercise. To investigate the effects of exercise training on growth performance, digestive enzymes, stress, and antioxidant capacity of large-mouth bass in a RAS, three training water flow velocities with three replicates were used in the present study: low water velocity: 0.5 body length per second (bl/s) (LV); medium water velocity: 1 bl/s (MV); and high water velocity: 1.5 bl/s (HV). 270 large-mouth bass (average initial body weight 47.51 ± 1.44 g, initial body length 12.71 ± 0.06 cm) were randomly divided into nine tanks (30 fish per tank). After 27 days experiment, the results showed that the growth performance of large-mouth bass, including feed intake, weight gain rate, and specific growth rate, in the HV group was significantly higher compared to the other groups. On the physiological level, the lipase and amylase activities were significantly increased in the HV group compared to the other groups. For the stress response parameters, the cortisol, glucose and lactate concentrations in the HV group were significantly increased, which may indicate higher stress in the HV group. Regarding the antioxidant enzyme activities, the activities of catalase (CAT) and glutathione peroxidase (GSH-PX) in the LV group were significantly higher than those in the HV group, which indicated that fish suffered higher oxidative stress in the LV group. Regarding the immune-related parameters, LZM and ACP activities had no significant differences among the groups, while AKP activities in the MV and HV groups were significantly higher than that in the LV group. Overall, the results demonstrated that exercise training had significant effects on the growth, digestion, stress, and immune response of large-mouth bass. It is suggested that exercise training with 1.5 bl/s can enhance fish growth, however, it also presents a potential risk of inducing stress in fish. Therefore, in rearing large-mouth bass in RAS, the setting of water flow velocity should not only focus on the growth of large-mouth bass but also consider its welfare.

中文翻译：

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运动训练对循环水养殖系统饲养的大口黑鲈（Micropterus salmoides）生长和生理的影响


大嘴鲈鱼最初生活在河流和湖泊中，现在经常在循环水产养殖系统（RAS）中饲养。但RAS的缺点是，在高密度养殖环境中，鱼类游动的空间非常有限，从而导致缺乏运动。为了研究运动训练对 RAS 中大口黑鲈生长性能、消化酶、应激和抗氧化能力的影响，本研究使用了三种训练水流速度和 3 个重复： 低水流速度：0.5 体长每秒 (bl/s) (LV)；介质水流速度：1 bl/s (MV)；高水流速度：1.5 bl/s (HV)。将270尾大口鲈鱼（平均初始体重47.51±1.44g，初始体长12.71±0.06cm）随机分为9个池（每池30条）。经过27天的实验，结果显示，HV组大口鲈鱼的生长性能，包括采食量、增重率、特定生长率均显着高于其他组。在生理水平上，与其他组相比，HV组的脂肪酶和淀粉酶活性显着增加。对于应激反应参数，HV组的皮质醇、葡萄糖和乳酸浓度显着升高，这可能表明HV组的应激更高。抗氧化酶活性方面，LV组过氧化氢酶（CAT）和谷胱甘肽过氧化物酶（GSH-PX）活性显着高于HV组，表明LV组鱼遭受更高的氧化应激。 免疫相关参数方面，LZM和ACP活性各组间无显着差异，而MV和HV组AKP活性显着高于LV组。总体而言，结果表明运动训练对大口鲈鱼的生长、消化、压力和免疫反应有显着影响。建议1.5 bl/s的运动训练可以促进鱼类生长，但也存在诱发鱼类应激的潜在风险。因此，在RAS养殖大口黑鲈时，水流速度的设置不仅要着眼于大口黑鲈的生长，还要考虑其福利。