Hematological responses of the grey carpet shark (Chiloscyllium punctatum) and the epaulette shark (Hemiscyllium ocellatum) to anoxia and re-oxygenation.
We compared the hematological responses of wild and captive populations of two closely related sharks to a standardized anoxic challenge and during a 12 hr recovery period in normoxia: the epaulette shark (Hemiscyllium ocellatum, Bonnaterre, 1788) and the grey carpet shark (Chiloscyllium punctatum, Müller and Henle, 1838). Compared to normoxic controls, a significant increase in hematocrit (captive 22.3%; wild 35.9%) coupled with a decline in mean corpuscular hemoglobin concentration occurred in epaulette sharks indicating erythrocyte swelling in response to anoxia. However, the grey carpet shark had a significantly increased hematocrit (captive 27.2%; wild 29.3%), erythrocyte count (captive 37.6%; wild 46.3%) and hemoglobin concentration (captive 31.9%; wild 31.5%), suggesting a release of erythrocytes into the circulation and/or hemoconcentration in response to anoxia. Plasma glucose concentrations were maintained in both wild and captive epaulette sharks and in wild grey carpet sharks during anoxia but increased significantly after 2 hr of re-oxygenation (epaulette: captive 55.8%; wild 50.1%; grey carpet shark: wild 70.3%) and remained elevated for 12 hr. Captive grey carpet sharks had an immediate increase in plasma glucose concentrations after anoxia (96.4%), which was sustained for 12 hr of re-oxygenation. Lactate concentrations significantly increased in captive and wild animals of both species after anoxia, reaching a peak at 2 hr of re-oxygenation. Both species showed significant, yet divergent, hematological changes in response to anoxia and re-oxygenation, which may not only prolong their survival and assist in recovery but also reflect their respective ecophysiological adaptations to the extreme environments that they inhabit.
Chapman
Clint A
CA
Hypoxia and Ischemia Research Unit, School of Physiotherapy and Exercise Science, Griffith University, Gold Coast Campus, Queensland, Australia.
Renshaw
Gillian M C
GM
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D004195:Disease Models, Animal; D004906:Erythrocyte Count; D006400:Hematocrit; D006454:Hemoglobins / Q000032:analysis; D000860:Hypoxia / Q000097:blood*; D019344:Lactic Acid / Q000097:blood; D015427:Reperfusion Injury / Q000097:blood*; D012754:Sharks / Q000502:physiology*; D013045:Species Specificity
D001786:Blood Glucose; D006454:Hemoglobins; D019344:Lactic Acid