Hematologia e bioquímica sangüínea do boto Vermelho Inia Geoffrensis (de Blainville, 1817)

Abstract

The river dolphins are the less known and more threatened cetaceans of the world. The Amazon river dolphin (Inia geoffrensis) is endemic and widely distributed in the Orinoco and Amazon River Basins. Looking forward to improve the knowledge about its biology and physiology, the present study reports hematological and plasma constituents values from 109 wild Amazon river dolphins from Sustainable Development Reserve Mamirauá. The blood samples were done during November of 2004 and 2005. The blood was drawn from the ventral surface of caudal peduncle, and occasionally from the vessels of the caudal fluke and flippers. A comparison between stored samples was done to verify the viability of them after 60 days in a –80°C freezer. Correlation tests between the blood parameters and the cardiac and respiratory frequencies were done to evaluate the effects of stress in blood values. Few hematological and plasma chemical differences were found between males and females, with exception of mean corpuscular hemoglobin concentration (MCHC) and alkaline phosphatase activity, both higher in males. Among age classes, the calves showed the highest values to almost all parameters. Younger, growing animals characteristically showed higher levels of calcium and alkaline phosphatase activity associated with the continued bone development. The calves also had higher creatine phosphokinase activity; higher lymphocyte counts and higher total leucocytes counts. This significant elevated number of leucocytes may be due to the still development immune system of immature animals. Only the erythrocyte sedimentation rate and the eosinophil percentage were higher in adults. Pregnant females showed characteristically higher values of four plasma constituents involved in energetic metabolism: Albumin, amylase, cholesterol, triglyceride; and urea either, probably as a result of higher food consumption in order to supply the energetic requirements during pregnancy. The freezing storage of the serum for 60 days markedly changed 13 of 19 serum plasma constituents. The aspartate aminotrasferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase activities decreased about 27%, 23% e 23%, respectively. The albumin, calcium, cholesterol, iron, glucose, magnesium and urea levels also decreased after freezing (22%, 40%, 26%, 47%, 40% e 48%, respectively). Otherwise, the gamma glutamyl transpeptidase (GGT) activity, and the free and total bilirrubin levels, showed small but significant increase. The positive correlation found between the leukocyte count and the respiratory frequency was induced by the highest number of these cells in immature animals, as well as the naturally elevated respiratory frequency in this age class. It is not possible to affirm that apparently more stressed animals (higher respiratory frequency) have higher number of circulating leucocytes.