47 research outputs found

    Blood chemistry of wild brazilian coscoroba swans during molt

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    The Coscoroba Swan (Coscoroba coscoroba) is an unusual member of the Anatidae found in South America, from the Falkland Islands and Tierra del Fuego through Chile and Argentina, Uruguay, and Paraguay as far north as Mato Grosso do Sul in Brazil. The species is not threatened globally, but some local populations have declined and the status of others is unknown. The objective of this study was to quantify the plasma chemistry of a wild population of Coscoroba Swans in southern Brazil during their molting period. We captured 12 chicks, 14 juveniles, and 31 mature birds. The following blood parameters were measured: glucose, cholesterol, triglycerides, HDL cholesterol, uric acid, creatin-kinase, aspartate amino transferase, alanine-aminotransferase, alkaline phosphatase, amylase, and pancreatic amylase. Significant differences between males and females were not observed for any of the parameters, and only the levels of alkaline phosphatase differed significantly among age groups. © Wildlife Disease Association 2010.Peer Reviewe

    Morphometric sex determination of young Ospreys Pandion haliaetus using discriminant analysis

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    Capsule Discriminant functions based on morphometric variables provide a reliable method for sex identification of free-living and hacked young Ospreys. Aims To describe an easy, accurate and low-cost method for sex determination of fully grown nestling and fledgling Ospreys Pandion haliaetus based on morphometric measurements. Methods Four different measurements were taken in 114 birds (40-73 days old) and a DNA analysis, using PCR amplification, was carried out for sex identification. A forward stepwise discriminant analysis was performed to build the best explanatory discriminant models, which were subsequently validated using statistics and external samples. Results Our best discriminant function retained forearm and tarsus as the best predictor variables and classified 95.1% of the sample correctly, supported also by external cross-validations with both hacked and free-living birds. Moreover, a discriminant function with only forearm as predictor showed a similar high correct classification power (93.4%). Conclusions These discriminant functions can be used as a reliable and immediate method for sex determination of young Ospreys since they showed high discriminant accuracy, close to that of molecular procedures, and were supported by external cross-validations, both for free-living and hacked birds. Thus, these morphometric measurements should be considered as standard tools for future scientific studies and management of Osprey populations. © 2010 British Trust for Ornithology.Peer Reviewe

    Genes involved in sex determination and the influence of temperature during the sexual differentiation process in fish: A review

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    This review attempts to group the recent hypotheses involved in the complex system of determination and sex differentiation in fish. Based on recent literature, we relate the key genes involved in the genomic cascade as the Cyp19, Dmrt1, Sox9, Foxl2, Esr, Dax1, Sf1 and Amh1, and still little known action of temperature on them. As the sex reversal is a highly desired process in fish farming aiming at obtaining male mono-sexual populations (due to weight gain of males), several techniques based on direct and indirect manipulation of phenotypic sex are being tested. Recent surveys show the use of temperature as alternative to the process of sex reversal. However, high or low temperatures have limited effect, in addition to there being a window of sex reversal in which temperature acts, varying from species to species. Thus, we draw a parallel with the role of temperature in the process of sex reversal and its effect on genes of the genomic cascade, which has been the subject of several studies that attempt to explain how temperature would be acting in this process. Intracellular receptors, such as those used for steroid hormones, act as transcription factors to regulate target genes moving between the nucleus and cytoplasm and, in the hormone absence, are linked to the complex of heat shock protein 90 kDa (Hsp90). Through this mechanism, it is possible to predict that fluctuations in temperature can influence the action of hormones, the increased transcription of genes involved in steroidogenesis and hence in sexual differentiation, becoming an alternative to explain where the temperature is acting. However, this literature review discusses the correlations between the genomic cascade, the action of intracellular receptors and the influence of temperature within this large system of determination and sex differentiation in fish.Keywords: Fish, gene, sex differentiation, temperatureAfrican Journal of Biotechnology Vol. 12(17), pp. 2129-214

    Morphometry and Mortality of Nile Tilapia fingerlings in two different treatments with temperature

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    The objective of this work is to present the mortality rates of Nile Tilapia (Oreochromis niloticus) subjected to two different temperature treatments, the morphometric measurements and body mass in two different phases in terms of age for each temperature and, morphologically identify differences that may be attributed to sexual dimorphism and that will determine the best age to collect animals for gonads analysis. Two treatments with water temperature were performed: 35° C and 25° C. Animals were killed in two steps: 35° C (71 and 92 days after hatching) and 25° C (112 and 131 days after hatching). The mortality record was performed by direct visualization, morphometry and weighing. The sexing was performed by gonadal histopathology. The treatment at 35° C showed lower mortality indicating that the fish would be more suited to higher temperatures. In contrast, the treatment at 25° C showed significant difference between variables and males with when the animals were 131 days after hatching. Through the morphometric data analysis, animals aged less than 131 days after hatching are morphologically able to gonadal identification on the Supreme strain

    Occurrence of Apicomplexa protozoa in wild birds in the Northeast region of Brazil

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    Abstract Protozoa of the Apicomplexa phylum are worldwide distributed with capacity to infect endothermic animals. The study of these protozoa in wild birds in Brazil is scarce. This study aimed to evaluate the occurrence of apicomplexan protozoa in wild birds in the Northeast of Brazil. From October to December 2019, brain tissue samples were collected from 71 captive birds from the Wild Animal Screening Center of the Pernambuco State (CETRAS-Tangara) and 25 free-living birds from the Caatinga biome in Rio Grande do Norte, totaling 96 animals (41 species). Brain fragments were subjected to molecular diagnosis by nested PCR for the 18s rDNA gene of Apicomplexa parasites, followed by DNA sequencing. This gene was detected in 25% (24/96) of the samples, and it was possible to perform DNA sequencing of 14 samples, confirming three genera: Isospora, Sarcocystis and Toxoplasma from eight bird species (Amazona aestiva, Coereba flaveola, Egretta thula, Paroaria dominicana, Sporophila nigricollis, Cariama cristata, Columbina talpacoti, Crypturellus parvirostris). The occurrence these coccidia in wild birds provides important epidemiological information for the adoption of preventive measures for its conservation. Future studies are needed to better understand the consequence of Apicomplexa infection in birds in Caatinga and Atlantic Forest biomes

    Swimming with Predators and Pesticides: How Environmental Stressors Affect the Thermal Physiology of Tadpoles

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    To forecast biological responses to changing environments, we need to understand how a species’s physiology varies through space and time and assess how changes in physiological function due to environmental changes may interact with phenotypic changes caused by other types of environmental variation. Amphibian larvae are well known for expressing environmentally induced phenotypes, but relatively little is known about how these responses might interact with changing temperatures and their thermal physiology. To address this question, we studied the thermal physiology of grey treefrog tadpoles (Hyla versicolor) by determining whether exposures to predator cues and an herbicide (Roundup) can alter their critical maximum temperature (CTmax) and their swimming speed across a range of temperatures, which provides estimates of optimal temperature (Topt) for swimming speed and the shape of the thermal performance curve (TPC). We discovered that predator cues induced a 0.4uC higher CTmax value, whereas the herbicide had no effect. Tadpoles exposed to predator cues or the herbicide swam faster than control tadpoles and the increase in burst speed was higher near Topt. In regard to the shape of the TPC, exposure to predator cues increased Topt by 1.5uC, while exposure to the herbicide marginally lowered Topt by 0.4uC. Combining predator cues and the herbicide produced an intermediate Topt that was 0.5uC higher than the control. To our knowledge this is the first study to demonstrate a predator altering the thermal physiology of amphibian larvae (prey) by increasing CTmax, increasing the optimum temperature, and producing changes in the thermal performance curves. Furthermore, these plastic responses of CTmax and TPC to different inducing environments should be considered when forecasting biological responses to global warming.Peer reviewe

    Epidemiological trends of HIV/HCV coinfection in Spain, 2015-2019

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    Altres ajuts: Spanish AIDS Research Network; European Funding for Regional Development (FEDER).Objectives: We assessed the prevalence of anti-hepatitis C virus (HCV) antibodies and active HCV infection (HCV-RNA-positive) in people living with HIV (PLWH) in Spain in 2019 and compared the results with those of four similar studies performed during 2015-2018. Methods: The study was performed in 41 centres. Sample size was estimated for an accuracy of 1%. Patients were selected by random sampling with proportional allocation. Results: The reference population comprised 41 973 PLWH, and the sample size was 1325. HCV serostatus was known in 1316 PLWH (99.3%), of whom 376 (28.6%) were HCV antibody (Ab)-positive (78.7% were prior injection drug users); 29 were HCV-RNA-positive (2.2%). Of the 29 HCV-RNA-positive PLWH, infection was chronic in 24, it was acute/recent in one, and it was of unknown duration in four. Cirrhosis was present in 71 (5.4%) PLWH overall, three (10.3%) HCV-RNA-positive patients and 68 (23.4%) of those who cleared HCV after anti-HCV therapy (p = 0.04). The prevalence of anti-HCV antibodies decreased steadily from 37.7% in 2015 to 28.6% in 2019 (p < 0.001); the prevalence of active HCV infection decreased from 22.1% in 2015 to 2.2% in 2019 (p < 0.001). Uptake of anti-HCV treatment increased from 53.9% in 2015 to 95.0% in 2019 (p < 0.001). Conclusions: In Spain, the prevalence of active HCV infection among PLWH at the end of 2019 was 2.2%, i.e. 90.0% lower than in 2015. Increased exposure to DAAs was probably the main reason for this sharp reduction. Despite the high coverage of treatment with direct-acting antiviral agents, HCV-related cirrhosis remains significant in this population

    First successful breeding of reintroduced ospreys pandion haliaetus in mainland Spain

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    In 2003 a reintroduction program of osprey started in the region of Andalusia, SW Spain, in order to recover the former breeding population in mainland Spain and to improve the situation of the species in the Mediterranean basin. From 2003 to 2009, 129 young ospreys were released by means of hacking. In 2009, the first breeding pair reared successfully three chicks in the Odiel Marshes for the first time in mainland Spain since 1981, when the species become extinct. The first breeding pair constitutes a significant indicator for the evaluation of the project and the beginning of a future population.Peer Reviewe

    Plasma alkaline phosphatase as a sensitive indicator of age and skeletal development in wild coscoroba swans

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    Context. Recent studies have suggested that plasma alkaline phosphatase (ALP) can be used to assess skeletal development as well as health status in wild animals. Aims. However, the information about age-related dynamics of ALP in birds, especially in precocial species, is very scarce. Therefore, before ALP measurements can be effectively interpreted, it is necessary to determine its normal variation for each species, age group and sex. Methods. Here, we report total-ALP levels of free-living coscoroba swans (Coscoroba coscoroba) from the most important breeding and moulting population in Brazil. Data were gathered during the moulting period and categorised according to sex and the following three different age classes: chick (n=11), young (n=14) and mature (n=29). Key results. ALP levels were related to the longitudinal measure of the bones, gradually diminishing with age and showing significant differences among birds of different age classes. In all age groups, no effect of sex on T-ALP concentration was detected. Conclusions. We conclude that measuring ALP facilitates the discrimination among different-aged individuals with similar plumage characteristics and body size. © CSIRO 2010.Peer Reviewe
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