Scaling effects on hypoxia tolerance in the Amazon fish Astronotus ocellatus (Perciformes: Cichlidae): contribution of tissue enzyme levels

• Published in: Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology Vol. 125; no. 2; pp. 219 - 226
• Main Authors: Almeida-Val, V.M.F, Val, A.L, Duncan, W.P, Souza, F.C.A, Paula-Silva, M.N, Land, S
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 01-02-2000
• Subjects: Amazon basin; Animals; Astronotus; Body Weight; Brain - enzymology; Cichlids; Enzyme scaling; Hypoxia survivorship; L-Lactate Dehydrogenase - metabolism; Liver - enzymology; Malate Dehydrogenase - metabolism; Muscle Fibers, Fast-Twitch - enzymology; Myocardium - enzymology; Oxygen - physiology; Perches - physiology; Seasons; Statistics as Topic; Tissue Extracts; Hypoxia survivorship; Enzyme scaling; Amazon basin; Astronotus; Cichlids
• ISSN: 1096-4959; 1879-1107
• DOI: 10.1016/S0305-0491(99)00172-8

Astronotus ocellatus is one of the most hypoxia tolerant fish of the Amazon; adult animals can tolerate up to 6 h of anoxia at 28°C. Changes in energy metabolism during growth have been reported in many fish species and may reflect the way organisms deal with environmental constraints. We have analyzed enzyme levels (lactate dehydrogenase, LDH: EC 1.1.1.27; and malate dehydrogenase, MDH: EC 1.1.1.37) in four different tissues (white muscle, heart, liver, and brain) from different-sized animals. Both enzymes correlate with body size, increasing the anaerobic potential positively with growth. To our knowledge, this is the first description of scaling effects on hypoxia tolerance and it is interesting to explore the fact that hypoxia survivorship increases due to combining effects of suppressing metabolic rates and increasing anaerobic power as fish grow.