Physiological responses in jeju, Hoplerythrinus unitaeniatus, (Characiformes, Erythrinidae), to atmospheric air exposure.

Abstract

The physiological responses to air exposure were analyzed in jeju, Hoplerythrinus unitaeniatus at 1, 6 and 12 hours of exposure and 1 e 6 hours after returning to water environment. Plasma cortisol and glucose were significantly higher than those of control group after 1, 6 and 12 hours of air exposure, respectively. Acid-base and ionic unbalances during air exposure were evidenced by plasma pH and Na+ and K+ concentration following pH recovery as fish returned to water environment. Ammonia accumulation was found in all experimental groups increasing continuously during air exposure. During the recovery period in water there was a reduction in plasma ammonia concentration but it was significantly higher than the controls. Plasma lactate showed a slightly increase during air exposure and was significantly higher than the controls only 1 hour after recovery in water while piruvate increased after 6 hour in water. Hematocrit, red blood cells, hemoglobin concentration and mean corpuscular hemoglobin concentration increased significantly during air exposure. Air exposure can be characterized as an stressor agent to H. unitaeniatus and imply in physiological adjustments to keep the O2 transfer from air to tissue and homeostasis as well as energy mobilization.