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The aim of the study was to evaluate whether supplementation with different levels of selenium (Se) can change the biochemical and electrolytic components of semen, causing an improvement in seminal quality in rams. Thirty animals were kept in an intensive pen system, fed with hay and commercial ration, allocated into five groups (six animals/pen) and supplemented with a mineral mixture containing Omg (G1), 5mg (G2), 10mg (G3), 15mg (G4) and 20mg (G5) of Se/kg. Each group received a different treatment every 56 days and treatments were rotated between groups following a dynamic sequence. Semen samples were collected by electroejaculation after the end of each treatment to evaluate the levels of fructose, citric acid, potassium (K), sodium (Na), calcium (Ca), Se, zinc (Zn), manganese (Mn), sulfur (S) and lead (Pb). The statistical design was a 5x5 Latin square. The different levels of Se supplementation evaluated maintained the concentrations of electrolytes and minerals in the semen at the required levels and did not change the sperm quality, concluding that higher intakes of Se do not cause antagonistic effects on the absorption and subsequent action of other essential minerals supplied to the animals and still maintains electrolyte balance.

O objetivo do estudo foi avaliar se a suplementação com diferentes níveis de selênio (Se) pode alterar os componentes bioquímicos e eletrolíticos do sêmen, ocasionando, por conseguinte, uma melhoria na qualidade seminal em carneiros. Foram utilizados 30 animais, mantidos em sistema intensivo de baias, alimentados com feno e ração comercial, sendo alocados em cinco grupos (seis animais/baia) e suplementados com uma mistura mineral contendo 0mg (G1), 5mg (G2), 10mg (G3), 15mg (G4) e 20mg (G5) de Se/kg. Cada grupo recebeu um tratamento diferente a cada 56 dias, e foi realizado um rodízio de tratamentos entre os grupos seguindo uma sequência dinâmica. Amostras de sêmen foram colhidas por eletroejaculação após o fim de cada tratamento, a fim de se avaliarem os níveis de frutose, ácido cítrico, potássio (K), sódio (Na), cálcio (Ca), Se, zinco (Zn), manganês (Mn), enxofre (S) e chumbo (Pb). O desenho estatístico foi um quadrado latino 5x5. Os diferentes níveis de suplementação de Se avaliados mantiveram as concentrações de eletrólitos e de minerais do sêmen nos níveis exigidos e não modificaram a qualidade espermática, concluindo-se que maiores ingestões de Se não causam efeitos antagônicos na absorção e subsequente ação de outros minerais essenciais fornecidos aos animais e ainda mantêm o equilíbrio eletrolítico.

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Gonadal sex differentiation in teleost fish shows greater plasticity as compared to other vertebrates, as it can be influenced by a variety of factors such as exogenous sex steroids. Exogenous estrogens, such as 17ß-estradiol (E2), can induce feminization when administered during early embryonic development. However, the mechanisms underlying the E2-induced feminization are not fully understood, especially in Neotropical species. Therefore, the aim of this study was to evaluate the effects of E2 administration on the phenotypic sex characteristics, histological assessment of the gonads, and the expression of selected genes in Astyanax altiparanae exposed to dietary E2 prior to gonadal differentiation. At 4 days post-hatch (dph), groups of 30-40 undifferentiated larvae were fed with a diet containing varying amounts of E2 for 28 days, and fish were sampled at 90 dph. Previous studies revealed that ovary formation in A. altiparanae occurred at 58 dph, whereas the first sign of testis formation was found at 73 dph. In relation to the control, E2 exposure increased the proportion of phenotypic females in 120% and 148.4% for 4 and 6 mg E2/Kg, respectively. However, histological analysis revealed that treatments did not affect gonadal sex ratio between males and females, but induced intersex (testis-ova) in the group treated with 6 mg E2/Kg food. Treatment with E2 also altered gonadal transcript levels of a selected number of genes implicated in sexual differentiation. Males overexpressed dmrt1, sox9 and amh following E2 treatment as compared to control. Females showed increased mRNA levels of dmrt1 and sox9, which might be related to the down-regulation of cyp19a1a after E2 exposure. In summary, E2 exposure during early gonadal development affected male secondary characteristics without changing the gonadal sex ratio, and altered expression of genes implicated in sexual differentiation.

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The stink bug Pachycoris torridus is a pest of great agricultural importance due to its records on culture of physic nut (Jatropha curcas), which is the raw material for biodiesel production. An interesting feature of this insect is its high phenotypic variability, a characteristic that resulted in it being classified as a new species on eight separate occasions. In the suborder Heteroptera, the heterochromatin pattern is specific and often allows species to be differentiated. To confirm whether there is differentiation between specimens of P. torridus with different color patterns (yellow, orange, brown, and red), samples were analyzed cytogenetically using the C-banding method. During meiotic prophase, the four color patterns analyzed showed a large heterochromatic chromocenter, consisting of a combination of both sex chromosomes (X and Y). Thus, the present study reports chromosomal homogeneity in different color patterns of P. torridus and highlights the importance of this tool in the description of new species.

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The stink bug Pachycoris torridus is listed among the most polyphagous insects in the world and it is a major pest of diverse crops, in particular the physic nut Jatropha curcas, which is used as a raw material for biodiesel production. A peculiar characteristic of this species is its high phenotypic variability, a characteristic that makes identification difficult: P. torridus has been described as a new species eight times. Thus, to aid in identification, genetic characterization of this insect was performed. We verified that, due to the high genetic variability of P. torridus, several genetic patterns exist that result in the same phenotype.

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Few cytogenetic studies have been undertaken using aquatic heteropterans and the nucleolar behavior of these insects has been described in only four species, Limnogonus aduncus, Brachymetra albinerva, Halobatopsis platensis, and Cylindrostethus palmaris. The nucleolus is a cellular structure related to biosynthetic activity and it exhibits a peculiar behavior in the heteropterans of the Triatominae subfamily; it persists during all stages of meiosis. Thus, this study aims to analyze spermatogenesis in Martarega brasiliensis, with an emphasis on nucleolar behavior. Twenty M. brasiliensis adult males were used and collected from the Municipal reservoir in the city of São José do Rio Preto, São Paulo, Brazil. The species were fixed in methanol:acetic acid (3:1), then dissected, and the testicles were extracted, torn apart, and impregnated with silver ions. During prophase, the nuclei of M. brasiliensis were composed of the nucleolus and nucleolar corpuscles, which varied in number from one to four, emphasizing that this insect has great synthetic activity during meiosis. The analysis of cells in metaphase I showed that M. brasiliensis presents a nucleolar organizing region in at least one autosome. Furthermore, the phenomenon of nucleolar persistence was not observed. All spermatids presented nucleolar markings that varied in number and position according to the stage of elongation. Moreover, it was also possible to highlight the presence of a vesicle in spermatids. Thus, this paper describes the nucleolar behavior of M. brasiliensis and highlights important characteristics during spermatogenesis, thus, increasing the knowledge about the biology of these aquatic heteropterans.

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The development of piatã grass fertilized with phosphorus sources with different solubilities in water was evaluated. The experiment was developed in the unit of Aquidauana of UEMS, MS, from February to August, 2012. Four treatments were evaluated: control (without phosphorus fertilization), slow solubility, fast solubility (readily available), and mixed solubility sources of phosphorus (FH Pasture(r)). It was adopted a randomized blocks design with four blocks and four replicates in a total of 16 pastures (0.5 ha each one). Measurements were performed weekly to evaluate structural characteristics and morphogenic variables of the plants. Data were submitted to a variance analysis according to the model. When necessary, the means of treatments with different phosphorus fertilizer sources were compared with the control using the Dunnett test and with other treatments by using student's t test. The significance level of 5% was adopted in all analysis. No significant effect was observed (P 0.05) in the evaluated traits in the first year of the experiment.

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The development of piatã grass fertilized with phosphorus sources with different solubilities in water was evaluated. The experiment was developed in the unit of Aquidauana of UEMS, MS, from February to August, 2012. Four treatments were evaluated: control (without phosphorus fertilization), slow solubility, fast solubility (readily available), and mixed solubility sources of phosphorus (FH Pasture(r)). It was adopted a randomized blocks design with four blocks and four replicates in a total of 16 pastures (0.5 ha each one). Measurements were performed weekly to evaluate structural characteristics and morphogenic variables of the plants. Data were submitted to a variance analysis according to the model. When necessary, the means of treatments with different phosphorus fertilizer sources were compared with the control using the Dunnett test and with other treatments by using student's t test. The significance level of 5% was adopted in all analysis. No significant effect was observed (P 0.05) in the evaluated traits in the first year of the experiment.(AU)

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