Ecophysiological interactions and water-related physicochemical parameters among freshwater stingrays / Interações ecofisiológicas e dos parâmetros físico-químico da água em arraias de água doce

Abstract The objective of this study was to compare and correlate the ecology of neonates and young individuals of Potamotrygon wallacei, Potamotrygon motoro and Paratrygon aiereba with regard to their hematological profile and the physicochemical parameters of the water that they inhabit. Principal component analysis (PCA) on the complete blood count revealed total variation of 72.92%, thus demonstrating a differentiation system for oxygen demand. On the other hand, P. motoro was considered to be an intermediate species, given that its complete blood count characteristics interacted with both P. wallacei and with P. aiereba. The interaction among the biochemical variables was shown to total 64.67% of the factors. This allowed differentiation of P. wallacei from P. aiereba, while P. motoro maintained an intermediate position. These characteristics of differentiation within the preferred environment corroborate the PCA of the present study and confirm that these species can be differentiated through considering the complete blood count and biochemical parameters. The PCA on water properties showed 68.57% differentiation, mainly comprising the x axis (49.44%). It can be affirmed that P. motoro has the capacity to inhabit the preferential areas of P. wallacei and P. aiereba, as well as occupying localities in which other stingrays are not found. In conclusion, P. wallacei presents patterns differentiating it from P. aiereba, while P. motoro is a species that presents intermediate characteristics. The latter can be considered to be a more broadly distributed species regarding its ecophysiological characteristics.

Resumo Este trabalho tem por objetivo investigar o perfil hematológico e os parâmetros físico-químicos da água, comparando e correlacionando ecologicamente entre neonatos e jovens de Potamotrygon wallacei (arraia cururu), Potamotrygon motoro e Paratrygon aiereba. A análise de componentes principais (PCA) do hemograma revelou um total 72,92% de variação, constituindo-se em um sistema de diferenciação na demanda por oxigênio. P. wallacei apresenta diferenciação no eixo X quando comparada a P. aiereba, por outro lado P. motoro constitui-se como uma espécie intermediária que apresenta as características do hemograma interagindo tanto com P. wallacei quanto com P. aiereba. A interação entre as variáveis bioquímica demonstram um total de 64,67% dos fatores, no qual foi possível diferenciar, a arraia P. wallacei de P. aiereba, tendo P. motoro uma aspecto de espécie intermediária entre as demais. Esses aspectos de diferenciação de ambiente de preferência corroboraram a PCA obtida no presente estudo e confirmam que essas espécies podem ser diferenciadas quando se considerar as variáveis referentes ao hemograma e a bioquímica. Nos íons, no trombograma e no leucograma, não foi possível diferenciar as espécies. O PCA das propriedades da água foi constituído por 68,57% de diferenciação que se constituiu principalmente no eixo x (49,44%). É possível confirmar que P. motoro tem a capacidade de habitar as áreas preferências de P. wallacei e P. aiereba, além do mais esta possui uma localidade que as demais arraias não são encontradas. Conclui-se que P. wallacei, apresenta padrões diferenciados de P. aiereba, além do mais P. motoro é uma espécie que apresenta características intermediárias entre as descritas, o qual pode ser considerado uma espécie com distribuição mais ampla em seus aspectos ecofisiológicos.

Cyrilia sp. (Apicomplexa: Haemogregarinidae) in the Amazonian freshwater stingray Potamotrygon wallacei (cururu stingray) in different hydrological phases of the Rio Negro / Cyrilia sp. (Apicomplexa: Haemogregarinidae) na arraia de água doce Amazônica Potamotrygon wallacei (arraia cururu) em diferentes fases do ciclo hidrológico do Rio Negro

Abstract Intraerythrocytic parasites are frequently found in fish, including elasmobranchs. The Amazonian rivers present well defined annual hydrological cycles that results in drastic modifications of the environmental conditions with deep implications in the life cycle of the whole associated biota in those fluvial systems. The freshwater stingray Potamotrygon wallacei (stingray cururu) is a new species restricted to the Middle Rio Negro basin and it is subject to strong alterations in their natural habitats (igapós) a result of the constant variations in the water level of Rio Negro. This work demonstrates the occurrence of intraerythrocytic parasite Cyrilia sp. in this stingray species. Additionally, the prevalence and quantification of hemoparasites in different phases of Rio Negro were also established. Field sampling was carried in the Archipelago of Mariuá, Middle Rio Negro, involving different stages of the water cycle. The intraerythrocytic parasites were quantified by direct counting in blood smears using a total counting of 2000 erythrocytes in each blood smear. The presence of parasites intraerythrocytic generates changes in the morphology of blood cell. The largest amount of the hemoparasites was recorded in the drought period. We observed a decreasing tendency in the number of parasites in the blood between the drought periods and inundation. We concluded that the level of Negro River influences the incidence of intraerythrocytic parasites in the cururu stingray and the drought represents the period of larger susceptibility to the infestation.

Resumo Parasitas intraeritrocitários são frequentemente encontrados em peixes, incluindo elasmobrânquios. Os rios Amazônicos possuem ciclos hidrológicos anuais que resultam em modificações drásticas nas condições ambientais, com implicação profunda no ciclo de vida associada a biota dos sistemas fluviais. A arraia de água doce Potamotrygon wallacei (arraia cururu) é uma nova espécie restrita a bacia do médio Rio Negro e sujeita a fortes alterações em seus habitats naturais (igapós) resultantes das constantes variações do nível de água do Rio Negro. Este trabalho demonstra a ocorrência de parasita intraeritrocitário Cyrilia sp. em espécimes de arraias de água doce. Além disso, a prevalência e quantificação de hemoparasitas em diferentes fases do Rio Negro foi estabelecida. Coletas de campo foram realizadas no Arquipélago de Mariuá, médio Rio Negro, envolvendo diferentes fases do ciclo hidrológico. Os parasitas intraeritrocitários foram quantificados por contagem direta em esfregaços de sangue usando a contagem total de 2000 eritrócitos em cada esfregaço sanguíneo. A presença de parasitas intraeritrocitários gera alterações na morfologia da célula sanguínea. A maior quantidade dos hemoparasitas foi registrado no período de seca. Observou-se a tendência de diminuição no número de parasitas no sangue entre o período de seca e de cheia. Concluiu-se que o nível de Rio Negro influencia a incidência de parasitas intraeritrocitários na arraia cururu, e a seca representa o período de maior susceptibilidade à infestação.

Ecophysiological interactions and water-related physicochemical parameters among freshwater stingrays.

The objective of this study was to compare and correlate the ecology of neonates and young individuals of Potamotrygon wallacei, Potamotrygon motoro and Paratrygon aiereba with regard to their hematological profile and the physicochemical parameters of the water that they inhabit. Principal component analysis (PCA) on the complete blood count revealed total variation of 72.92%, thus demonstrating a differentiation system for oxygen demand. On the other hand, P. motoro was considered to be an intermediate species, given that its complete blood count characteristics interacted with both P. wallacei and with P. aiereba. The interaction among the biochemical variables was shown to total 64.67% of the factors. This allowed differentiation of P. wallacei from P. aiereba, while P. motoro maintained an intermediate position. These characteristics of differentiation within the preferred environment corroborate the PCA of the present study and confirm that these species can be differentiated through considering the complete blood count and biochemical parameters. The PCA on water properties showed 68.57% differentiation, mainly comprising the x axis (49.44%). It can be affirmed that P. motoro has the capacity to inhabit the preferential areas of P. wallacei and P. aiereba, as well as occupying localities in which other stingrays are not found. In conclusion, P. wallacei presents patterns differentiating it from P. aiereba, while P. motoro is a species that presents intermediate characteristics. The latter can be considered to be a more broadly distributed species regarding its ecophysiological characteristics.

Cyrilia sp. (Apicomplexa: Haemogregarinidae) in the Amazonian freshwater stingray Potamotrygon wallacei (cururu stingray) in different hydrological phases of the Rio Negro.

Intraerythrocytic parasites are frequently found in fish, including elasmobranchs. The Amazonian rivers present well defined annual hydrological cycles that results in drastic modifications of the environmental conditions with deep implications in the life cycle of the whole associated biota in those fluvial systems. The freshwater stingray Potamotrygon wallacei (stingray cururu) is a new species restricted to the Middle Rio Negro basin and it is subject to strong alterations in their natural habitats (igapós) a result of the constant variations in the water level of Rio Negro. This work demonstrates the occurrence of intraerythrocytic parasite Cyrilia sp. in this stingray species. Additionally, the prevalence and quantification of hemoparasites in different phases of Rio Negro were also established. Field sampling was carried in the Archipelago of Mariuá, Middle Rio Negro, involving different stages of the water cycle. The intraerythrocytic parasites were quantified by direct counting in blood smears using a total counting of 2000 erythrocytes in each blood smear. The presence of parasites intraerythrocytic generates changes in the morphology of blood cell. The largest amount of the hemoparasites was recorded in the drought period. We observed a decreasing tendency in the number of parasites in the blood between the drought periods and inundation. We concluded that the level of Negro River influences the incidence of intraerythrocytic parasites in the cururu stingray and the drought represents the period of larger susceptibility to the infestation.

THE CONSUMPTION OF RED PUPUNHA (BACTRIS GASIPAES KUNTH) INCREASES HDL CHOLESTEROL AND REDUCES WEIGHT GAIN OF LACTATING AND POST-LACTATING WISTAR RATS.

INTRODUCTION: The lactating and post-lactating periods are marked by large metabolic change. Production of milk is 60% lipid dependent. We reported in a recent scientific meeting that Red pupunha palm tree fruit increases HDL cholesterol in lactating rats. This study evaluated if consumption of Red Pupunha by adult female rats has a beneficial impact on the lipid metabolism of lacting and post-lacting adult rats. OBJECTIVE: Evaluate if consumption of red pupunha has a beneficial effect in the lipid metabolism of lacting and post-lacting adult Wistar rats. RESEARCH METHODS: Four groups including two for control; (1) control adult lactating rats, (2) control adults post-lactating rats; and two experimental groups; (3) pupunha adults lactating rats and (4) pupunha adult post-lactating rats were evaluated and compared regarding: weight gain, food consumption, plasma total protein, glucose, total lipid, triglycerides, total cholesterol and HDL-cholesterol levels. The mean difference and its 95% confidence intervals were used for group comparisons. Group comparisons were evaluated by using analysis of variance (one-way ANOVA). The statistical significance of the pairwise differences among groups was assessed by using the two-sided Tukey test. RESULTS: There were no important differences in food consumption, plasma glucose, total lipids and triglycerides among groups. The red pupunha lactating group gain less weight showing lower body mass index (BMI) than controls (p < 0.05). Total cholesterol was lower in red pupunha lactating than in controls but not in the red pupunha post-lactating group as compared to controls. Triglycerides were lower in the post-lactating red pupunha group as compared to the control group (p = 0.039) but not for the lactating groups. Red pupunha lactating and post-lactating groups had higher HDL-cholesterol than their corresponding control groups (p ≤ 0.01). CONCLUSION: Original findings include the beneficial effect of red pupunha in post-lactating rats increasing the HDL-cholesterol and lowering the BMI. Red pupunha was confirmed to increase HDL-cholesterol in lactating rats. These results suggest that red pupunha is a healthy fruit to be consumed during lactating and post-lactating periods as it is related to better lipid profile and less body weight gain.

Stress responses of the endemic freshwater cururu stingray (Potamotrygon cf. histrix) during transportation in the Amazon region of the Rio Negro.

Potamotrygon cf. histrix (cururu stingray) are endemic freshwater stingrays from the middle region of the Rio Negro in the Brazilian Amazon basin and are exported worldwide as ornamentals caught by artisanal fishermen. The transport process from capture to final destination is long and stressful. This study quantified stress related changes in corticosterone, blood and water samples (baseline, pre-transport, 3h, 12h and 24h) analyzed during a transport experiment which tested two water additives (tetracycline and the probiotic Efinol). There was a significant stepwise increase in corticosterone levels in stingrays over transport time in combination with osmoregulatory disturbances suggesting a stress related role of this corticosteroid. There were significant increases in water conductivity, Na(+) and K(+) losses and ammonia excretion. Blood parameters such as glucose, hematocrit, red blood count and urea did not change significantly during the experiment. Glucose levels did not increase significantly during transport and this may be due to the fact that other elasmobranchs have been shown to rely more on ketone bodies for energy rather than glucose and produce ammonia as their main nitrogenous waste. The mineralocorticoid action of this hormone has been shown in elasmobranchs and most likely plays a role in osmotic homeostasis. The use of probiotic and especially antibiotic should be avoided since no beneficial effects were observed.

Enzymes of energy metabolism in hatchlings of amazonian freshwater turtles (Testudines, Podocnemididae).

The metabolic profiles of selected tissues were analyzed in hatchlings of the Amazonian freshwater turtles Podocnemis expansa, P. unifilis and P. sextuberculata. Metabolic design in these species was judged based on the key enzymes of energy metabolism, with special emphasis on carbohydrate, lipid, amino acid and ketone body metabolism. All species showed a high glycolytic potential in all sampled tissues. Based on low levels of hexokinase, glycogen may be an important fuel for these species. The high lactate dehydrogenase activity in the liver may play a significant role in carbohydrate catabolism, possibly during diving. Oxidative metabolism in P. sextuberculata appears to be designed for the use of lipids, amino acids and ketone bodies. The maximal activities of 3-hydroxyacyl-CoA dehydrogenase, malate dehydrogenase, glutamine dehydrogenase, alanine aminotransferase and succinyl-CoA keto transferase display high aerobic potential, especially in muscle and liver tissues of this species. Although amino acids and ketone bodies may be important fuels for oxidative metabolism, carbohydrates and lipids are the major fuels used by P. expansa and P. unifilis. Our results are consistent with the food habits and lifestyle of Amazonian freshwater turtles. The metabolic design, based on enzyme activities, suggests that hatchlings of P. unifilis and P. expansa are predominately herbivorous, whereas P. sextuberculata rely on a mixed diet of animal matter and vegetation.

Enzymes of energy metabolism in hatchlings of amazonian freshwater turtles (Testudines, Podocnemididae) / Enzimas do metabolismo energético em quelônios amazônicos (Testudines, Podocnemididae) recém-eclodidos

The metabolic profiles of selected tissues were analyzed in hatchlings of the Amazonian freshwater turtles Podocnemis expansa, P. unifilis and P. sextuberculata. Metabolic design in these species was judged based on the key enzymes of energy metabolism, with special emphasis on carbohydrate, lipid, amino acid and ketone body metabolism. All species showed a high glycolytic potential in all sampled tissues. Based on low levels of hexokinase, glycogen may be an important fuel for these species. The high lactate dehydrogenase activity in the liver may play a significant role in carbohydrate catabolism, possibly during diving. Oxidative metabolism in P. sextuberculata appears to be designed for the use of lipids, amino acids and ketone bodies. The maximal activities of 3-hydroxyacyl-CoA dehydrogenase, malate dehydrogenase, glutamine dehydrogenase, alanine aminotransferase and succinyl-CoA keto transferase display high aerobic potential, especially in muscle and liver tissues of this species. Although amino acids and ketone bodies may be important fuels for oxidative metabolism, carbohydrates and lipids are the major fuels used by P. expansa and P. unifilis. Our results are consistent with the food habits and lifestyle of Amazonian freshwater turtles. The metabolic design, based on enzyme activities, suggests that hatchlings of P. unifilis and P. expansa are predominately herbivorous, whereas P. sextuberculata rely on a mixed diet of animal matter and vegetation.

O perfil metabólico de vários tecidos foi analisado em quelônios aquáticos recém-eclodidos: Podocnemis expansa, P. unifilis e P. sextuberculata. O potencial metabólico dessas espécies foi avaliado por meio das atividades absolutas das enzimas do metabolismo energético com ênfase no metabolismo dos carboidratos, lipídios, aminoácidos e corpos cetônicos. Todas as espécies estudadas apresentaram alto potencial glicolítico em todos os tecidos analisados. Com base nos baixos níveis da enzima hexoquinase, as reservas de glicogênio podem ser importantes substratos energéticos para estas espécies. A alta atividade da lactato desidrogenase no fígado pode indicar que este órgão desempenha um importante papel no metabolismo dos carboidratos, possivelmente relacionado com a resistência ao mergulho prolongado. O perfil metabólico de P. sextuberculata parece organizado para utilizar preferencialmente lipídios, aminoácidos e corpos cetônicos. Os dados das atividades máximas das enzimas 3-hidroxi-acil-Co A desidrogenase, malato desidrogenase e succinil-Co A ceto-transferase, especialmente no músculo branco e no fígado dessa espécie corroboram esta hipótese. Por outro lado, os carboidratos e os lipídios parecem ser os principais substratos metabólicos de P. expansa e P. unifilis, muito embora, os corpos cetônicos e aminoácidos sejam importantes metabólitos para sustentar o potencial oxidativo nessas espécies. Os dados enzimáticos parecem estar correlacionados com o hábito alimentar e o estilo de vida dos quelônios de água doce da Amazônia. O perfil metabólico sugere que os recém-eclodidos de P. unifilis e P. expansa são predominantemente herbívoros, enquanto que P. sextuberculata pode depender de uma dieta mista de material vegetal e proteína animal.

Biochemical and hematological reference ranges for Amazon freshwater turtle, Podocnemis expansa (Reptilia: Pelomedusidae), with morphologic assessment of blood cells.

Blood parameters are useful to measure physiological disturbances in chelonians. Thus they can provide important information for the diagnosis and prognosis of diseases. The aim of this paper was to determine the reference range of plasma glucose, total protein, triglycerides, cholesterol and urea levels, as well as hematocrit, hemoglobin, red blood cell, thrombocyte and white blood cell counts for healthy Podocnemis expansa (Schweigger, 1812), bred in a turtle farm in the Amazonas State, Brazil. Plasma glucose, hemoglobin, mean corpuscular volume (MCV), lymphocytes and heterophils were the parameters with the smallest variations. Significant (p<0.001) correlations between red blood cells count and hematocrit and hemoglobin concentration were found. Turtle P. expansa had lymphocytes, azurophils, heterophils, eosinophils and basophils with morphologic features similar to the ones of others turtles species. No investigated blood parameter was influenced by sex. In further studies, the established reference ranges might be useful for the health assessment of this turtle species.

Antioxidant processes of the wild tambaqui, Colossoma macropomum (Osteichthyes, Serrasalmidae) from the Amazon.

Colossoma macropomum, locally called tambaqui, is a freshwater migratory teleost that shows good tolerance to oxygen and pH changes in water, and both chemical-physical parameters change markedly during the day time and seasonal water level oscillations in the Amazon Basin. In order to obtain a general view about the basal levels of antioxidants in different tissues of wild tambaqui, enzymatic (superoxide dismutase and catalase) and non-enzymatic (alpha-tocopherol, beta-carotene, and glutathione) antioxidants and lipid peroxidation levels were assessed in the liver, blood and plasma of ten specimens collected during the dry season (September) in a pond near Manaus-AM, Brazil. Superoxide dismutase, catalase, and lipid peroxidation levels were high in the liver and low in the blood and plasma. Confirming previous results on tambaqui, catalase was detected in the blood of one specimen only. beta-Carotene was not found in any analyzed tissue, while alpha-tocopherol was found only in the liver (7.8 +/- 7.0 nmol g(-1), mean +/- S.E.M.) and plasma (4.3 +/- 0.9 nmol ml(-1)). Blood glutathione concentrations (2.4 +/- 0.17 mmol l(-1)) of tambaqui were comparable with those found in other Amazonian teleosts. Antioxidant defenses and lipid peroxidation contents from liver. blood and plasma exhibited interesting correlations. These relationships suggest that antioxidant defenses located in different tissues and in different sub-cellular compartments act in concert.

[Intermittent infusions of dobutamine in the treatment of chronic cardiac failure in the terminal stage]. / Perfusions intermittentes de dobutamine dans le traitement des défaillances cardiaques chroniques au stade terminal.

This study was designed to evaluate the efficacy of intermittent dobutamine infusions in patients with end-stage congestive heart failure. Twenty-four patients with NYHA Stage IV congestive heart failure were included. Mean age was 65.8 years (range 40-85). All patients were under optimal medical therapy with digitalis, diuretics and vasodilating agents. Diagnosis was coronary heart disease in 11 patients, dilated cardiomyopathy in 9, and valvular incompetence in 4. Dobutamine was given in an initial dosage of 2.5 micrograms/kg/min increased by 2.5 micrograms/kg/min every 15 minutes until the desired effect was achieved. Mean dosage was 10 micrograms/kg/min. Patients were given an identical infusion two weeks later, then at monthly intervals after improvement of the clinical status. Heart failure stage was improved in all patients: 14 patients were stage II and 10 were stage III. Ejection fraction failed to improve (19.5 +/- 10 to 18.5 +/- 5). Mortality rate was 5% at one year, 24% at two years, and 45% at four years.

Erythrocytic nucleoside triphosphates in marine fish.

1. Whole blood purine nucleotides were determined in 19 species of selachians and 27 species of marine teleosts. Concomitant ATP and GTP were revealed inside the erythrocytes of almost all species studied. 2. ATP seems to be the main potential modulator of oxygen affinity in rays, sharks and teleosts, and GTP was not detected in only two teleost species. 3. The mean erythrocytic NTP concentration and the ratio between NTP and intraerythrocytic Hb concentrations in rays were the lowest (2.3 mM and 0.6 respectively), increasing in sharks (3.8 mM and 1.0), and further in teleosts (5.9 mM and 2.1). 4. The intraerythrocytic phosphate contents probably reflect different adaptative strategies associated with the fish habits and habitats, and with the Root effect expression.