title: A comparison of constant acceleration swimming speeds when acceleration rates are different with critical swimming speeds in Chinese bream under two oxygen tensions.
abstract: To investigate the effect of acceleration rates on the constant acceleration test speed (U cat) and to compare U cat with the critical swimming speed (U crit) in Chinese bream (Parabramis pekinensis), the U cat test at acceleration rates of 0.05, 0.1, 0.2, 0.4 and 0.8 cm s(-2) and the U crit test in juvenile fish at 20 °C in either normoxia (>90 % saturation oxygen tension) or hypoxia (30 % saturation) were compared. The lactate concentration ([lactate]) of white muscle, liver and plasma and the glycogen concentration ([glycogen]) of white muscle and liver were also measured to identify whether tissue substrate depletion or tissue lactate accumulation correlated with exhaustion. The U cat decreased with the acceleration rate, and there was no significant difference between U crit and U cat at lower acceleration rates. Hypoxia resulted in lower U cat and U crit, and the difference increased with decreased acceleration rates of the U cat test, possibly due to the increased contribution of aerobic components in U crit or U cat at low acceleration rates. Hypoxia elicited a significant decrease in muscle [glycogen] and an increase in muscle and liver [lactate] in resting fish. All post-exercise fish had similar muscle [lactate], suggesting that tissue lactate accumulation may correlate with exercise exhaustion. Unlike hypoxia, exercise induced an increase in muscle [lactate] and a significant increase in plasma [lactate], which were worthy of further investigation. The similar swimming speed and biochemical indicators after exercise in the U crit and U cat groups at low acceleration rates suggested that U cat can be an alternative for the more frequently adopted protocols in U crit in Chinese bream and possibly in other cyprinid fish species.
authors.affiliation: Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing, 401331, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Wang
authors.affiliation: Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing, 401331, China.
authors.forename: Zhen-Dong
authors.initials: ZD
authors.lastname: Cao
authors.affiliation: Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing, 401331, China. shijianfu9@cqnu.edu.cn.
authors.forename: Shi-Jian
authors.initials: SJ
authors.lastname: Fu
mesh_terms: D000054:Acceleration; D000818:Animals; D003530:Cyprinidae / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D000860:Hypoxia / Q000503:physiopathology*; D019344:Lactic Acid / Q000097:blood / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D009132:Muscles / Q000378:metabolism; D010100:Oxygen; D013550:Swimming
chemical_list: D019344:Lactic Acid; D006003:Glycogen; D005947:Glucose; D010100:Oxygen
keywords: Biochemical indicators; Chinese bream; Oxygen tension; Swimming protocol; Swimming speed