title: The effect of prolonged exercise training on swimming performance and the underlying biochemical mechanisms in juvenile common carp (Cyprinus carpio).
abstract: To investigate the effect of prolonged exercise training on swimming performance and the underlying biochemical mechanisms in juvenile common carp (Cyprinus carpio), we measured the critical swimming speed (Ucrit), the excess post-exercise oxygen consumption (EPOC), the activity of red and white muscle enzymes [pyruvate kinase (PK), lactate dehydrogenase (LDH) and citrate synthase (CS)], the tissue substrates (glycogen and glucose content of muscle and liver) and metabolite (the lactate content of plasma and muscle) content of exercise-trained (60% Ucrit for 4 weeks) and non-trained fish. We also measured the biochemical indices of both trained and non-trained fish immediately after Ucrit, after exhaustive exercise and 1h after exhaustive exercise. The aerobic swimming performance, as indicated by Ucrit, increased significantly after exercise training, most likely because of the higher tissue metabolic capacity, as suggested by the higher CS activity in the red muscle tissue, and the higher energy store and more efficient substrate utilization, as suggested by higher liver and muscle glycogen contents at rest but lower tissue glycogen contents after Ucrit. The lower lactate content after Ucrit is most likely because of higher aerobic metabolic capacity, and (or) the clearance rate of lactate in trained fish may also contribute to improved aerobic swimming performance. Compared to Ucrit, exhaustive exercise elicited higher plasma and muscle lactate contents. The anaerobic metabolic performance is not affected by the exercise training, as suggested by the EPOC. However, trained fish did show higher lactate clearance rates, as suggested by lower muscle lactate content after a 1h recovery period following exhaustive exercise compared to non-trained fish. Furthermore, trained fish decreased their liver and muscle glycogen contents more profoundly after exhaustive exercise, suggesting that training can improve the substrate utilization during anaerobic exercise.
authors.affiliation: Laboratory of Evolutionary Physiology and Behavior, Chongqing Key Laboratory of Animal Biology, Chongqing Normal University, Chongqing 400047, China.
authors.forename: Wei
authors.initials: W
authors.lastname: He
authors.forename: Wei
authors.initials: W
authors.lastname: Xia
authors.forename: Zhen-Dong
authors.initials: ZD
authors.lastname: Cao
authors.forename: Shi-Jian
authors.initials: SJ
authors.lastname: Fu
mesh_terms: D000818:Animals; D002347:Carps / Q000378:metabolism* / Q000502:physiology; D002950:Citrate (si)-Synthase / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D018482:Muscle, Skeletal / Q000201:enzymology; D010101:Oxygen Consumption; D010805:Physical Conditioning, Animal; D005082:Physical Exertion; D011770:Pyruvate Kinase / Q000378:metabolism; D013550:Swimming / Q000502:physiology*
chemical_list: D019344:Lactic Acid; D006003:Glycogen; D007770:L-Lactate Dehydrogenase; D002950:Citrate (si)-Synthase; D011770:Pyruvate Kinase; D005947:Glucose
keywords: Common carp; Enzyme activity; Exercise training; Glycogen; Lactate; Swimming performance