Hematologia, bioquímica do sangue, parasitologia, microbiologia, algas epizoárias e histopatologia de Phrynops geoffroanus (Schweigger, 1812) (Testudinata, Chelidae), expostos a diferentes influências antrópicas no rio Uberabinha, Minas Gerais.

Abstract

Comparative studies of morphometry, microbiology, hematology, blood biochemistry, histopathology, hematozoary research, ectoparasites and epizoary algae were performed between two subpopulations of the freshwater turtle Phrynops geoffroanus captured in two areas of the Uberabinha River. One area drains regional agriculture (18º58'35 S and 48º17'11 W), while the second is predominantely urban (18º5'10 S and 48º18'09 W). From December, 1999 to January 2001, field and laboratory work were accomplished characterizing the two areas as to the geographical relief, the plant life on the river margins, the air temperature and relative humidity, microbiology and several physical-chemical parameters of the water and residues of organochlorine (agricultural chemical) from the river sediment. To test differences between the two areas, climatic data, twelve physical-chemical parameters and water instantaneous speed were analyzed using the Wilcoxon test at a 5% significance level. Significant differences in the relative humidity of the air, total dissolved solids, suspended solids, electric conductivity, temperature, transparency, nitrites and turbidity of the river water were all verified. The urbanized area presented smaller conservation in the margins vegetation, lowest air relative humidity, water with larger concentrations of total dissolved solids, suspended solids, nitrite, larger electric conductivity, smaller transparency, larger turbidity, larger variety of microorganisms and organochlorate residues, being that the transheptachlor, endossulfan and atrazine indexes were higher in the agricultural area.The different human-related influences on soil use were reflected in the composition of the flora on the river s margins and in the aquatic ecosystem, resulting in high levels mainly of phosphate, nitrogen, atrazine, transheptaclor, endosulfan and BHC, as well as water bacterial contamination. The fifty eight P. geoffroanus were captured in January of 2000, being 16 males and 16 females coming from the urban area and 12 males and 14 females from the agricultural area. To collect the Phrynops two funnel traps were used containing fish, chicken viscera and bovine heart as bait. The Phrynops were transported to the Reptiles Section at the Federal University of Uberlândia where they were sexed, marked individually and housed in concrete tanks. The ectoparasites and samples of the algae attached to the shells were collected and preserved. Blood samples were drawn for the glicemia determination. The morphometric data and the blood sample for hematozoary investigations together with hematological and biochemical blood analyses were also obtained from the turtles. Later, three males and three females from each subpopulation were sacrificed by decapitation for macroscopic analysis of the organs and histopathological studies. All the blood tests were performed during the summer. Analysis of the 15 morphometric characters and of the body mass data (ANOVA and ACP, 5% significance level) evidenced an accentuated sexual dimorphism; however, the different environmental conditions to which the two subpopulations were exposed didn't interfere in the size or in the form of the turtles. The microbiological analysis of the samples collected from the oral cavity, cloaca and the neck folds showed that the subpopulation from the urban area had a larger proportion of microorganisms in relation to that of the agricultural area (x2 = 31,0; P < 0,001). There were no significant differences among the proportions of microorganisms on body parts in relation to the geographical areas (x2= 0,017; P > 0,05). In both sample the oral cavity was the most infected (x2= 1,5897; P < 0,05). In the two subpopulations, the number of species of isolated microorganisms in the turtles was superior to the number of species found in the water of the river, with a few differences in the urban area. Although in this area a larger diversity of microorganisms, in the water and in the turtles, was found. A higher percentage of occurrence of the alga Basicladia chelonum, in the turtles shells was verified in the urban sample (43,8%) in relation to the agricultural sample (30,8%). Hemogregarine intraeritrocitary gametocytes were found in 27,6% of blood smears from P. geoffroanus, with a larger occurrence in the urban area. Ectoparasitism by leeches (Placobdella bistriata) was verified only in specimens from the urban area, and of the nine, six turtles were also infected by hemogregarine. Among the P. geoffroanus sacrificed, specimens from the agricultural area presented smaller amounts of fatty reserve tissue, more compact skeletal muscles, a more strong red color and dilation of some lung alveoli, indicating more physical activity compared with those from the urban area. The turtles from the urban area presented larger alterations as evidenced by the histopathological analysis, such as: discreet edema in the encephalon and the heart; cartilaginous formation in pulmonary alveolus and focal pneumonia; liver, pancreas, splein, kidney and stomach with inflamatory infiltrate and suggestive trematodes granulomas; hemossiderose in the liver and spleen. The hematological and biochemical data from the blood analysis were analyzed by analysis of variance (ANOVA, at a 5% significant level) for hypothesis testing and a difference of averages test (Tukey s test) to verify differences among the averages. Significant differences in relation to sex were obtained in 50% of the blood parameters (leucocyte numbers, eosinophyle percentages, hemoglobin, iron, phosphate, medium corpuscular hemoglobin, medium corpuscular hemoglobin concentration, prothrombin time, fibrinogen, ionized calcium, total proteins, albumin, alpha 1, alpha 2, gamma globulin, cholesterol high density lipoprotein and very low density lipoprotein, triglyceride, creatine kinase, gamma glutamil transferin, amilasys, lipase, uric acid, chloride and magnesium). In relation to the two geographical areas, 88% of the parameters were statistically significant (eritrocyte numbers, leucocytes, eosinophils, monocytes, heterophils, azurophils, hemoglobin, hematocrite, medium corpuscular hemoglobin and all the biochemical parameters, except to clotting blood). For the interaction area-sex analysis, 16% of the variables were significantly different (medium corpuscular hemoglobin, medium corpuscular hemoglobin concentration, leucocytes number, alkaline phosphatases, uric acid, beta globulin, iron and magnesium) between the two samples. The impact due to human intervention in terms of the different soil uses apparently caused environmental degradation interfering in most of the hematological and biochemical blood parameters between the two turtle subpopulations of the Uberabinha River. That, associated with the histopathological results, parasitological and the microbiological findings indicates that the environmental conditions, especially those related to the aquatic ecosystem, interfered in the physiology and could compromise the health of these turtles. Although the reference intervals of hemogram, electrophoresis and biochemical blood parameters used in the present study are important tools in the health control and diagnosis animal of diseases, they should not be considered as standard for this species, whose geographical distribution is wide, inhabiting ponds, streams and rivers with very diversified hidrogeochemical characteristics. Keywords: Phrynops geoffroanus, environmental contamination, morphometry, bacteria, epizoary algae, parasite infestation, hematology, histopathology, clinical biochemistry.