Respostas fisiológicas e bioquímicas do jeju Hoplerythrinus unitaeniatus (Characiformes, Erythrinidae) a exposição aérea
Abstract
The physiological and biochemical responses to air exposure were analyzed in jeju,
Hoplerythrinus unitaeniatus at 1(T1), 6 (T6) and 12 (T12) hours of exposure and 1
(TR1) e 6 (TR6) hours after returning to water environment. Plasma cortisol and
glucose were significantly higher than those of control group (T0) after 1 and 6 hours
and 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 (from
102.20 nmol/mL in T0 to 339.53 nmol/mL in T12). 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 (from 4115.42
nmol/mL in T0 to 6423.84 nmol/mL in TR1) while piruvate increased after 6 hour in
water (from 171.87 nmol/mL in T0 para 243.96 nmol/mL in TR6). Hematocrit, red
blood cells, hemoglobin concentration and mean corpuscular hemoglobin concentration
increased significantly during air exposure. On the first hour of air exposure the lipid
hydroperoxide (HP) increased. There was a reduction of catalase (CAT) and superoxide
dismutase (SOD) activity and an increase of glutathione peroxidase (GPX) 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.