Tese Michele Fagundes.pdf - Caunesp

Abstract
The number of species farmed in Brazil, including the pintado (Pseudoplatystoma
corruscans) has been increasing making necessary better knowledge of their physiology
and farming techniques. The aim of this study was evaluate the circadian variations of
blood cortisol and glucose without stresfull agents and physiological responses (blood
levels of cortisol and glucose; liver and muscle glycogen; plasma chloride and
osmolarity; hemathocrit, number e volume of red cells and hemoglobin) of juvenile fish
submitted to different farming conditions (12h transport; alteration of photoperiod - 24
h exposure to continuous light or continuous darkness; exposure to benzocaine,
phenoxyethanol and clove oil). There was no statistical among cortisol levels, but
numerically the day profile was different of the night profile, showing peaks of cortisol
secretion at the set up of the darkness and light. Blood glucose was not correlated to
cortisol profile and had the levels more constant during the night. In the transport
experiment, the cortisol levels increased along the procedure followed by a gradual
reduction that reached values below the control 48, 72 and 96 h after the operation.
Glucose increased after transport returning to basal levels within 72h as well muscle
lipid levels. Blood colesterol and protein also increased. Chloride was reduced after
transport as well as hematocrit, number of red cells and hemoglobin. Metabolic data
suggest the use of another energy source in place of glucose to attend the stress demand.
In the experiment in which fish were submitted to 24 h of light or darkness, blood
cortisol did not differ statistically, but the values found in fish under 24 h of light were
numerically higher compared to those of fish under darkness and both compared to
control fish. Glicemia was numerically reduced in fish under darkness. No
osmorregulatory disturbance was seen. Hematocrit, number of red cells and hemoglobin
had the same profile increasing after 24 and 72 h of exposure of either light or darkness
trending to be higher in fish exposed to light. Lately, fish were exposed to anesthetic
(25, 50 and 75 mg/L benzocaine; 0.2, 0.4 and 0.8 mL/L of phenoxyethanol and clove
oil). Blood cortisol levels reduced as the eugenol concentration increased, and the same
profile was observed with phenoyethanol. No difference was observed regarding
benzocaine. Similarly, glucose reduced with the anesthetics increased, being the lower
levels found in the lower concentrations of both anesthetics. Similar profile of reduction
was seen regarding to benzocaine and eugenol in hematocrit, number of red cells and
hemoglobin. In all three anesthetics, the lowest concentrations promoted the higher time
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