Page 89 - 《水产学报》2025年第7期

艾同喜，等 水产学报, 2025, 49(7): 079107

Effects of water velocity on swimming behavior, antioxidant capacity
and energy metabolic enzymes in Anguilla japonica

1,2
1
1
1
1,2*
2
AI Tongxi , LIU Jialun , LIU Jianyi , YANG Jun , SHANG Meijuan , ZHAO Feng ,
1,2*
2
JIANG Keji , GAO Lei , XU Jiayuan 2
1. College of Fisheries and Life Sciences, Shanghai Ocean University, Shanghai 201306, China;
2. East China Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Shanghai 200090, China
Abstract: The Anguilla japonica is a migratory fish species of significant economic importance. In intensive aquaculture sys-
tems, unfavorable rearing conditions can lead to immunosuppression, rendering the species more susceptible to pathogenic
infections. Moreover, following stock enhancement releases, the transition from artificial aquaculture environments to natural
ecosystems exposes A. japonica to challenges such as food scarcity and predation, which may compromise its survival and
adaptability. Proper flow training during artificial rearing and prior to stock enhancement has been demonstrated to improve
health status and enhance survival capacity in the wild to some extent. To date, no studies have examined the effects of flow
training on the antioxidative capacity and immune system of A. japonica. Additionally, research on the behavioral biology of
adult A. japonica remains limited. This study investigates the relationship between critical swimming speed and body length, as
well as the effects of different flow velocities on oxygen consumption rate, energy consumption per unit distance, antioxidative
capacity, nonspecific immunity, and energy metabolism. Using swimming performance testing equipment and circular flow
systems, physiological parameters were measured under four flow velocity conditions: static water (0.0 m/s), 0.1 m/s, 0.2 m/s,
and 0.3 m/s. The results revealed a linear positive correlation between critical swimming speed (U crit ) and body length, with the
relationship modeled as: U crit =1.44L+12.57. The relative critical swimming speed (U crit ') was described by the equation:
U crit '=−0.004 1L+1.896 0. Additionally, the relationship between water velocity and oxygen consumption rate (Mo 2 ) was
2
–5
2
expressed as: Mo 2 =0.005 8V +3.808 3V+34.709 0, while the cost of transport (COT) was modeled as: COT=1.145 0×10 V −
0.001 6V + 0.185 8. Regarding antioxidant indices, increases in water velocity significantly enhanced total antioxidant capacity
(T-AOC), hydroxyl radical scavenging capacity (HFR-SC), reduced glutathione (GSH) levels, and catalase (CAT) activity in
the serum of A. japonica. Notably, T-AOC and CAT activities in the 0.3 m/s group were significantly higher than in the still
water group, while GSH levels peaked at 0.2 m/s. In terms of liver enzyme activity, glutamate dehydrogenase (GDH) activity
increased with velocity, peaking at 0.2 m/s before declining. Meanwhile, pyruvate kinase (PK) activity was significantly higher
in the 0.3 m/s group compared to the still water group (P<0.05). These findings suggest that appropriate flow training (0.2–0.3
m/s) enhances the antioxidative capacity and energy metabolism efficiency of A. japonica, promoting healthier growth and
improving survival in natural environments. This study provides valuable guidance for health management during A. japonica
aquaculture and flow training design prior to stock enhancement.

Key words: Anguilla japonica; swimming behavior; oxygen consumption rate; antioxidant enzymes; energy metabolic
enzymes

Corresponding authors: LIU Jianyi. E-mail: liujy@ecsf.ac.cn;
JIANG Keji. E-mail: jiangkj@ecsf.ac.cn
Funding projects: Fundamental Research Funds for the East China Sea Fisheries Research Institute, Chinese Academy of Fish-
ery Sciences (2021Z02); National Key Research and Development Program of China (2019YFD0900405)

中国水产学会主办 sponsored by China Society of Fisheries https://www.china-fishery.cn
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