Pre-Slaughter Stunning Methods Influence the Meat Quality of Arapaima gigas Fillets.

The aim of this study was to evaluate the influence of different stunning methods on the meat quality of Arapaima gigas fillets from fish farming. A total of 48 specimens of A. gigas in the weight class 11.1 to 14.0 kg were investigated; these fish were subjected to different stunning methods for slaughter: ice asphyxia (IA), air asphyxia (AA), electronarcosis (EE) and hypothermia followed by bleeding (HB). Then, data were obtained from the analysis of pH, rigor mortis index (RI), water activity (Aw), instrumental texture (compression strength, firmness and adhesiveness) and blood glucose and via instrumental colourimetry. During the study, for up to 15 days of refrigerated storage, the methods provided pH values below 6.0. A. gigas submitted to EE and HB remained longer in the pre-rigor status. In addition, they expressed lower percentages of Aw. The EE method resulted in better texture assignments in the fillets. The blood glucose values indicated that the fish subjected to EE were less stressed. Concerning instrumental colourimetry, the fillets submitted to EE and HB showed greater luminosity; the fillets subjected to AA showed greater red-green colour intensity, while the fillets subjected to EE showed greater yellow-blue colour intensity. Therefore, the fish did not suffer stress with electronarcosis, and the fillets showed better preservation, juiciness, and tenderness.

Morphological, histopathological, ultrastructural and phylogenetic analysis of Henneguya archosargus n. sp. (Cnidaria, Myxosporea) infecting the sparid fish Archosargus probatocephalus in Brazilian waters.

The introduction of new fish species to the aquaculture industry is essential to halt the progressive decline of natural fish stocks. The sheepshead Archosargus probatocephalus is a commercially valuable sparid fish with potential for breeding in captivity, but with limited information regarding parasitic infections that could pose a significant threat for its sustainable production. Thus, the present study aimed to study the myxozoan diversity infecting A. probatocephalus. A novel Henneguya sp. was detected forming plasmodia in the gill lamellae of specimens inhabiting the Brazilian coast, and is characterized based on morphological, histopathological, ultrastructural, molecular, and phylogenetic data. Myxospore total length was 21.3 ± 0.8 µm, with myxospore body 10.0 ± 0.5 µm long, 6.2 ± 0.3 µm wide, and 4.8 ± 0.5 µm thick. Caudal appendages were 10.3 ± 0.5 µm long and did not present any type of coating. Two pyriform polar capsules, 3.4 ± 0.3 µm long and 1.5 ± 0.2 µm wide, each containing an isofilar polar tubule with 4-5 coils. Histopathological analyses showed large intralamellar polysporic plasmodia associated with vascular congestion of the gill filament and gill lamellae, as well as epithelial hyperplasia causing partial or total fusion of gill lamellae. Maximum likelihood and Baysesian inference SSU rDNA-based phylogenetic analyses showed the novel sequence grouped within the marine clade of Henneguya spp. that mostly parasitize fishes belonging to Eupercaria incertae sedis.

Hemagglutination in gill capillaries of sheepshead, Archosargus probatocephalus (Perciformes: Sparidae), infected by a myxosporidean.

During a survey Myxozoa, four specimens of the sheepshead (18 ± 1.5 cm and 59 ± 2.5 g) (Archosargus probatocephalus) were collected in the Ipioquinha river (Maceió/AL). Transmission electron microscopy observations revealed erythrocyte agglutinations in gill capillaries located near spherical cysts containing myxospores of the genus Henneguya. This hemagglutination partially or totally obstructed the gill capillaries. Erythrocytes occurred in close adherence to each other, with a closed intercellular space. A few lysed erythrocytes were observed among agglutinated cells. The reduced lumen of the capillaries was partially filled with amorphous dense homogenous material adhering to the erythrocytes. In addition, heterogeneous masses of irregular lower electron density were observed in the reduced channel of the capillary. The agglutinated erythrocytes appeared dense and homogenous, lacking cytoplasmic organelles. The nuclei had the appearance of normal condensed chromatin masses, generally without visible nucleoli. This occurrence of hemagglutination only in the capillaries located in close proximity to the developing myxozoan cysts suggests that parasite development may be a factor triggering erythrocyte agglutination. This is supported by previous experimental studies that showed a probable correlation between parasitic infections and hemagglutination. Nonetheless, further studies are necessary in order to better understand the physicochemical processes involved in this phenomenon.

Hemagglutination in gill capillaries of sheepshead, Archosargus probatocephalus (Perciformes: Sparidae), infected by a myxosporidean / Hemaglutinação em capilares branquiais de sargo-de-dente, Archosargus probatocephalus (Perciformes: Sparidae) infectado por um mixosporídeo

Abstract During a survey Myxozoa, four specimens of the sheepshead (18 ± 1.5 cm and 59 ± 2.5 g) (Archosargus probatocephalus) were collected in the Ipioquinha river (Maceió/AL). Transmission electron microscopy observations revealed erythrocyte agglutinations in gill capillaries located near spherical cysts containing myxospores of the genus Henneguya. This hemagglutination partially or totally obstructed the gill capillaries. Erythrocytes occurred in close adherence to each other, with a closed intercellular space. A few lysed erythrocytes were observed among agglutinated cells. The reduced lumen of the capillaries was partially filled with amorphous dense homogenous material adhering to the erythrocytes. In addition, heterogeneous masses of irregular lower electron density were observed in the reduced channel of the capillary. The agglutinated erythrocytes appeared dense and homogenous, lacking cytoplasmic organelles. The nuclei had the appearance of normal condensed chromatin masses, generally without visible nucleoli. This occurrence of hemagglutination only in the capillaries located in close proximity to the developing myxozoan cysts suggests that parasite development may be a factor triggering erythrocyte agglutination. This is supported by previous experimental studies that showed a probable correlation between parasitic infections and hemagglutination. Nonetheless, further studies are necessary in order to better understand the physicochemical processes involved in this phenomenon.

Resumo Durante pesquisa de mixozoários foram coletados quatro espécimes do peixes sargo-de-dente (18 ± 1.5 cm e 59 ± 2.5 g) (Archosargus probatocephalus), no rio Ipioquinha (Maceió/AL). Observações por microscopia eletrônica de transmissão revelaram aglutinação de eritrócitos em capilares branquiais localizados próximos a cistos esféricos, contendo mixosporos do gênero Henneguya. Essa hemaglutinação obstruiu parcial ou totalmente os capilares branquiais. Os eritrócitos apareceram em forte aderência entre si, com espaço intercelular fechado. Foram observados poucos eritrócitos lisados entre as células aglutinadas. O lúmen reduzido dos capilares foi parcialmente preenchido com material homogêneo denso amorfo aderido aos eritrócitos, além de massas livres heterogêneas de densidade eletrônica baixa e irregular observadas no canal reduzido dos capilares. Os eritrócitos aglutinados pareciam densos e homogêneos, sem organelas citoplasmáticas. Os núcleos apareceram como massas normais de cromatina condensada, geralmente sem nucléolos visíveis. A ocorrência de hemaglutinação apenas nos capilares, localizados nas proximidades dos cistos mixozoários, sugere que o desenvolvimento parasitário pode ser um fator desencadeante da aglutinação eritrocitária. Isso é corroborado por estudos experimentais anteriores que mostraram uma provável correlação entre infecções parasitárias e hemaglutinação. No entanto, novos estudos são necessários para melhor compreender os processos físico-químicos envolvidos neste fenômeno.

Oil impact on the environment and aquatic organisms on the coasts of the states of Alagoas and Sergipe, Brazil - A preliminary evaluation.

The oil spill off the coast of the Brazilian Northeast region is one of the most significant global events regarding contamination and environmental impact in recent years. This work evaluates the effects of oil spills on the Northeast coasts between Alagoas and Sergipe states from October 2019 to January 2020. Analysis of some sampling points of seawater revealed the presence of Hg, Cd, Pb, and Cu in levels above the maximum concentration limits established by the Brazilian legislation. For water quality parameters, phosphorus, nitrite, and turbidity showed statistically different values. However, the chromatographic profiles of oil obtained from different beaches were quite similar. Seawater, fishes, and massunins (bivalve) presented the main polycyclic aromatic hydrocarbons: naphthalene, phenanthrene, fluoranthene, fluorene, and acenaphthalene. Therefore, the concentration of organic and inorganic contaminants determined in different environmental locations served as a subsidy to assess the effect of the preliminary oil spill on the Brazilian coast.

Timing and Duration of Observation Periods of Foraging Behavior in Natural Grasslands.

The goals of this study were to evaluate the length of time grazing which should be monitored over a 24-h period to predict the grazing behavior of beef heifers within a season and determine the patterns of foraging activity over 24 h. A database was constructed between 2010 and 2012 for beef heifers managed under rotational grazing in a natural grassland. Grazing, rumination, and other activity times were assessed visually during 24 h on 15 occasions. Data were classified according to climatic seasons, generating 12 replicates in summer, 18 in spring, 24 in autumn, and 36 in winter. Treatments were the evaluation of four distinct periods: from sunrise to sunset (DAY-SUN), daylight duration from dawn to nightfall (DAYLIGHT), DAYLIGHT plus 2 h (DAYLIGHT+2), DAYLIGHT to midnight (DAYLIGHT to 0), and the entire 24 h period (CONTROL). Differences for grazing, rumination, and other activities were found in all seasons for the evaluation periods. Sampling sufficiency was reached only with the DAYLIGHT to 0 and CONTROL for all four climatic seasons. The DAYLIGHT to 0 treatment covered 75% of a 24-h period and 95% of the mean foraging time took place during this time interval. Considering grazing distribution during a day, in the warm seasons, the major grazing period during mornings occurred earlier than in the cool seasons, and in cool seasons, the grazing peak was observed during the afternoon. Visual observations from dawn until midnight represented the total grazing time and natural behavior of heifers and could be used to represent grazing activities for the entire day.

Frequency of the TP53 R337H variant in sporadic breast cancer and its impact on genomic instability.

The R337H is a TP53 germline pathogenic variant that has been associated with several types of cancers, including breast cancer. Our main objective was to determine the frequency of the R337H variant in sporadic breast cancer patients from Paraná state, South Brazil, its association with prognosis and its impact in genomic instability. The genotyping of 805 breast cancer tissues revealed a genotypic and allelic frequency of the R337H variant of 2.36% and 1.18%, respectively. In these R337H+ cases a lower mean age at diagnosis was observed when compared to the R337H-cases. Array-CGH analysis showed that R337H+ patients presented a higher number of copy number alterations (CNAs), compared to the R337H-. These CNAs affected genes and miRNAs that regulate critical cancer signaling pathways; a number of these genes were associated with survival after querying the KMplot database. Furthermore, homozygous (R337H+/R337H+) fibroblasts presented increased levels of copy number variants when compared to heterozygous or R337H- cells. In conclusion, the R337H variant may contribute to 2.36% of the breast cancer cases without family cancer history in Paraná. Among other mechanisms, R337H increases the level of genomic instability, as evidenced by a higher number of CNAs in the R337H+ cases compared to the R337H-.

Ultrastructure of intracytoplasmic Rickettsia-like infection of the gills of the teleost Archosargus probatocephalus (Sparidae) in northeastern Brazil.

A histopathological survey was conducted to investigate the presence of microparasites in fish Archosargus probatocephalus in a river near Maceió, Brazil. Light microscope observations of fragments of gill showed the presence of small cysts containing numerous myxospores that were morphologically identified as Henneguya. Transmission electron microscopy observations further revealed several gill cells containing groups of prokaryotic cells within large cytoplasmic vacuoles. Each infected host cell displayed a single vacuole containing a variable number of Rickettsia-like cells (up to 11), some of which presented the dumbbell shape characteristic of binary fission. The Rickettsia-like cells were pleomorphic, without a nucleus and with chromatin dispersed in the cytoplasm. They had a thin electron-dense wall of Gram-negative type. The morphology of these prokaryotic was similar to those of the order Rickettsiales and was described as a Rickettsia-like organism. Histopathological evaluation showed that several vacuole membranes had a lysed appearance. Some had ruptured, thus allowing direct contact between the Rickettsia-like organism and the cytoplasm of the host cell. The rupturing of the branchial epithelium may have contributed towards reduction of the surface area of the gills, but it is not possible to say that this was the cause of the host's death.

Genetic characterization of tambaqui stocks from two pisciculture stations in the lower São Francisco River / Caracterização genética de estoques de tambaqui de duas estações de piscicultura no baixo rio São Francisco

Pisciculture has been an important part of the economy in many regions of Brazil, and the tambaqui (Colossoma macropomum) stands out as one of the country's most commercialized native freshwater fish species. Loss of genetic variability can affect characteristics such as reproduction and growth rates, as well as disease resistance and is of great concern in this field. Molecular markers such as mitochondrial DNA genes have been increasingly used to understand genetic variability in species of economic importance. This study aimed to characterize the genetic variability of tambaqui populations reared in two fish farms (Itiúba, AL and Betume, SE) of the lower São Francisco River by analyzing the control region and ATPase genes of mitochondrial DNA. Sequencing of samples from progenies and breeding individuals identified 42 haplotypes (32 unique), of which four haplotypes were shared between the two fish farms as a result of a founder effect, because individuals from Itiúba formed the stock of the Betume fish farming Station. Haplotype diversity was high in both locations. Analysis of Molecular Variance (AMOVA) revealed greater genetic variation within populations (96.76%) than between them (3.24%) and the FST value (0.03) indicated low genetic differentiation between the two populations. The observed high genetic variability can be explained by the number of breeders in the two fish farms (200 in Itiúba and 1400 in Betume) and the breeding management system, which seems to be effective in maintaining stock variability.

A piscicultura tem ocupado um lugar de destaque na economia de muitas regiões do Brasil, e o tambaqui (Colossoma macropomum) se sobressai por ser uma das espécies nativas de peixes de água doce mais comercializadas do país. A diminuição da variabilidade genética pode afetar características como as taxas de reprodução e crescimento, bem como resistência a doenças e é de grande preocupação nesse ramo. Marcadores moleculares, como os genes do DNA mitocondrial, vem sendo cada vez mais utilizados para investigar a variabilidade genética em espécies de importância econômica. Assim, este estudo teve como objetivo caracterizar a variabilidade genética de populações de tambaqui cultivados em duas pisciculturas (Itiúba, AL e Betume, SE) do baixo Rio São Francisco, utilizando a região controle e os genes da ATPase do DNA mitocondrial. O sequenciamento de amostras de progênies e reprodutores identificou 42 haplótipos (32 únicos). Destes, quatro haplótipos foram compartilhados entre as duas pisciculturas estudadas, o que é resultado de um efeito fundador, uma vez que indivíduos de Itiúba foram levados para compor o estoque da Estação de Piscicultura de Betume. A diversidade haplotípica foi alta em ambas as localidades. Análise de Variância Molecular (AMOVA) demonstrou maior variação genética dentro das populações (96.76%) do que entre elas (3.24%) e o valor de Fst (0.03) indicou pouca diferenciação genética entre as duas populações analisadas. A alta variabilidade genética encontrada pode ser explicada pelo número de reprodutores nas duas pisciculturas (200 em Itiúba e 1400 em Betume) e o manejo reprodutivo, que parece ser eficaz na manutenção da variabilidade de estoques.

Heifers rearing on natural grassland under rotational grazing during warm season / Recria de novilhas em pastagem natural sob pastoreio rotativo na primavera-verão

ABSTRACT: This study aimed to evaluate the effect of two rest intervals between grazing on the structural characteristics of pasture and performance of beef heifers in Campos grassland under rotational grazing. The treatments were two intervals between 375 and 750 DD (degree-days) grazing, based on the cumulative thermal sum for leaf expansion of native grasses belonging to capture and conservation groups of resources dominant in a natural grassland. The experiment was conducted during 151 days from October 2015 to March 2016, and twenty-four Braford heifers tests mean age = 12 months; mean body weight = 220kg (± 27.8) were used. The pre-grazing total forage mass (FMt) was on average 3791 kgMSha-1 and did not differ between treatments and season, the same occurred with the non-tussock FM. The average stocking rate was 469 kg ha-1 in both treatments. The average daily gain varied only between seasons, 0.102 kg animal-1 day-1 during spring and 0.372 kg animal-1 day-1 during summer. During the 151 evaluation days, the gain per area was a 103 kgha-1. The use of rest intervals between grazing based on the leaf elongation of dominant grasses, when applied to the areas of Campos grasslands, provided nutritional conditions to reach the target body weight for breeding 24 months old beef heifers.

RESUMO: O estudo objetivou avaliar o efeito de dois intervalos de descanso entre pastoreios nas características estruturais do pasto e desempenho de novilhas de corte em pastagens naturais manejadas em pastejo rotativo. Os tratamentos foram dois intervalos entre pastejos de 375 e 750 GD (graus dia), baseados na soma térmica da duração de elongação foliar média de gramíneas de grupos de captura e conservação dos recursos dominantes de uma pastagem natural. O experimento foi conduzido no período de outubro de 2015 a março de 2016, com duração de 151 dias e os períodos experimentais divididos em primavera e verão. Foram utilizadas 24 novilhas teste da raça Braford, com idade inicial na média de 12 meses, e de peso corporal médio de 220 kg (± 27,8). A Massa de forragem total (FMt) pré-pastejo foi em média de 3791 kgMSha-1 e não diferiu entre tratamentos e estação, o mesmo ocorreu com a FM de estrato não touceira. A taxa de lotação média foi de 469 kgha-1 em ambos os tratamentos. O ganho médio diário variou apenas entre estações, com médias de 0,102 kganimal-1dia-1 na primavera e 0,372 kganimal-1dia-1 no verão. O ganho por área durante os 151 dias de avaliação foi em média de 103 kgha-1. As pastagens naturais submetidas a intervalos de descanso entre pastoreios baseados na elongação foliar de gramíneas dominantes, independente do tratamento utilizado, proporcionam ritmos de ganhos médios diários compatíveis com a meta de peso corporal, a ser atingida aos 24 meses, para que as novilhas possam ser acasaladas.

Genetic characterization of tambaqui stocks from two pisciculture stations in the lower São Francisco River / Caracterização genética de estoques de tambaqui de duas estações de piscicultura no baixo rio São Francisco

Pisciculture has been an important part of the economy in many regions of Brazil, and the tambaqui (Colossoma macropomum) stands out as one of the country's most commercialized native freshwater fish species. Loss of genetic variability can affect characteristics such as reproduction and growth rates, as well as disease resistance and is of great concern in this field. Molecular markers such as mitochondrial DNA genes have been increasingly used to understand genetic variability in species of economic importance. This study aimed to characterize the genetic variability of tambaqui populations reared in two fish farms (Itiúba, AL and Betume, SE) of the lower São Francisco River by analyzing the control region and ATPase genes of mitochondrial DNA. Sequencing of samples from progenies and breeding individuals identified 42 haplotypes (32 unique), of which four haplotypes were shared between the two fish farms as a result of a founder effect, because individuals from Itiúba formed the stock of the Betume fish farming Station. Haplotype diversity was high in both locations. Analysis of Molecular Variance (AMOVA) revealed greater genetic variation within populations (96.76%) than between them (3.24%) and the FST value (0.03) indicated low genetic differentiation between the two populations. The observed high genetic variability can be explained by the number of breeders in the two fish farms (200 in Itiúba and 1400 in Betume) and the breeding management system, which seems to be effective in maintaining stock variability.(AU)

A piscicultura tem ocupado um lugar de destaque na economia de muitas regiões do Brasil, e o tambaqui (Colossoma macropomum) se sobressai por ser uma das espécies nativas de peixes de água doce mais comercializadas do país. A diminuição da variabilidade genética pode afetar características como as taxas de reprodução e crescimento, bem como resistência a doenças e é de grande preocupação nesse ramo. Marcadores moleculares, como os genes do DNA mitocondrial, vem sendo cada vez mais utilizados para investigar a variabilidade genética em espécies de importância econômica. Assim, este estudo teve como objetivo caracterizar a variabilidade genética de populações de tambaqui cultivados em duas pisciculturas (Itiúba, AL e Betume, SE) do baixo Rio São Francisco, utilizando a região controle e os genes da ATPase do DNA mitocondrial. O sequenciamento de amostras de progênies e reprodutores identificou 42 haplótipos (32 únicos). Destes, quatro haplótipos foram compartilhados entre as duas pisciculturas estudadas, o que é resultado de um efeito fundador, uma vez que indivíduos de Itiúba foram levados para compor o estoque da Estação de Piscicultura de Betume. A diversidade haplotípica foi alta em ambas as localidades. Análise de Variância Molecular (AMOVA) demonstrou maior variação genética dentro das populações (96.76%) do que entre elas (3.24%) e o valor de Fst (0.03) indicou pouca diferenciação genética entre as duas populações analisadas. A alta variabilidade genética encontrada pode ser explicada pelo número de reprodutores nas duas pisciculturas (200 em Itiúba e 1400 em Betume) e o manejo reprodutivo, que parece ser eficaz na manutenção da variabilidade de estoques.(AU)

Ultrastructure of intracytoplasmic Rickettsia-like infection of the gills of the teleost Archosargus probatocephalus (Sparidae) in northeastern Brazil / Ultraestrutura de Rickettsia intracitoplasmática infectando as brânquias do teleósteo Archosargus probatocephalus (Sparidae) no Nordeste do Brasil

A histopathological survey was conducted to investigate the presence of microparasites in fish Archosargus probatocephalus in a river near Maceió, Brazil. Light microscope observations of fragments of gill showed the presence of small cysts containing numerous myxospores that were morphologically identified as Henneguya. Transmission electron microscopy observations further revealed several gill cells containing groups of prokaryotic cells within large cytoplasmic vacuoles. Each infected host cell displayed a single vacuole containing a variable number of Rickettsia-like cells (up to 11), some of which presented the dumbbell shape characteristic of binary fission. The Rickettsia-like cells were pleomorphic, without a nucleus and with chromatin dispersed in the cytoplasm. They had a thin electron-dense wall of Gram-negative type. The morphology of these prokaryotic was similar to those of the order Rickettsiales and was described as a Rickettsia-like organism. Histopathological evaluation showed that several vacuole membranes had a lysed appearance. Some had ruptured, thus allowing direct contact between the Rickettsia-like organism and the cytoplasm of the host cell. The rupturing of the branchial epithelium may have contributed towards reduction of the surface area of the gills, but it is not possible to say that this was the cause of the hosts death.(AU)

Um levantamento histopatológico foi realizado para pesquisar a presença de microparasitas, no peixe Archosargus probatocephalus, em um rio próximo a Maceió, Brasil. Observações ao microscópio óptico de fragmentos de brânquias mostraram a presença de pequenos cistos contendo numerosos mixósporos, identificados morfologicamente como Henneguya. Ocasionalmente, na microscopia eletrônica de transmissão, foram observados vários corpos citoplasmáticos de inclusão, grupo aparentemente de células procarióticas que vivem dentro de um grande vacúolo citoplasmático de algumas células branquiais. As células hospedeiras infectadas tinham um único vacúolo contendo um número variável de células do tipo Rickettsia, até 11, algumas das quais em forma do haltere, característica da fissão binária. Essas células eram pleomórficas sem núcleo, tendo a cromatina dispersa no citoplasma e possuíam uma parede densa de elétrons finos do tipo Gram-negativo. A morfologia dessas células procarióticas foi semelhante àquelas da ordem Rickettsiales e foram descritas como organismos tipo Rickettsiae. A histopatologia mostra várias membranas de vacúolos circundantes com aspetos lisados, enquanto outras apresentam rupturas que mostram contato direto do organismos tipo Rickettsiae com o citoplasma da célula hospedeira. A ruptura do epitélio branquial pode ter contribuído para a redução da superfície das brânquias, mas não é possível afirmar que foi a causa da morte do hospedeiro.(AU)

Heifers rearing on natural grassland under rotational grazing during warm season / Recria de novilhas em pastagem natural sob pastoreio rotativo na primavera-verão

This study aimed to evaluate the effect of two rest intervals between grazing on the structural characteristics of pasture and performance of beef heifers in Campos grassland under rotational grazing. The treatments were two intervals between 375 and 750 DD (degree-days) grazing, based on the cumulative thermal sum for leaf expansion of native grasses belonging to capture and conservation groups of resources dominant in a natural grassland. The experiment was conducted during 151 days from October 2015 to March 2016, and twenty-four Braford heifers tests mean age = 12 months; mean body weight = 220kg (± 27.8) were used. The pre-grazing total forage mass (FMt) was on average 3791 kgMSha-1 and did not differ between treatments and season, the same occurred with the non-tussock FM. The average stocking rate was 469 kg ha-1 in both treatments. The average daily gain varied only between seasons, 0.102 kg animal-1 day-1 during spring and 0.372 kg animal-1 day-1 during summer. During the 151 evaluation days, the gain per area was a 103 kgha-1. The use of rest intervals between grazing based on the leaf elongation of dominant grasses, when applied to the areas of Campos grasslands, provided nutritional conditions to reach the target body weight for breeding 24 months old beef heifers.(AU)

O estudo objetivou avaliar o efeito de dois intervalos de descanso entre pastoreios nas características estruturais do pasto e desempenho de novilhas de corte em pastagens naturais manejadas em pastejo rotativo. Os tratamentos foram dois intervalos entre pastejos de 375 e 750 GD (graus dia), baseados na soma térmica da duração de elongação foliar média de gramíneas de grupos de captura e conservação dos recursos dominantes de uma pastagem natural. O experimento foi conduzido no período de outubro de 2015 a março de 2016, com duração de 151 dias e os períodos experimentais divididos em primavera e verão. Foram utilizadas 24 novilhas teste da raça Braford, com idade inicial na média de 12 meses, e de peso corporal médio de 220 kg (± 27,8). A Massa de forragem total (FMt) pré-pastejo foi em média de 3791 kgMSha-1 e não diferiu entre tratamentos e estação, o mesmo ocorreu com a FM de estrato não touceira. A taxa de lotação média foi de 469 kgha-1 em ambos os tratamentos. O ganho médio diário variou apenas entre estações, com médias de 0,102 kganimal-1dia-1 na primavera e 0,372 kganimal-1dia-1 no verão. O ganho por área durante os 151 dias de avaliação foi em média de 103 kgha-1. As pastagens naturais submetidas a intervalos de descanso entre pastoreios baseados na elongação foliar de gramíneas dominantes, independente do tratamento utilizado, proporcionam ritmos de ganhos médios diários compatíveis com a meta de peso corporal, a ser atingida aos 24 meses, para que as novilhas possam ser acasaladas.(AU)

Heifers rearing on natural grassland under rotational grazing during warm season

ABSTRACT: This study aimed to evaluate the effect of two rest intervals between grazing on the structural characteristics of pasture and performance of beef heifers in Campos grassland under rotational grazing. The treatments were two intervals between 375 and 750 DD (degree-days) grazing, based on the cumulative thermal sum for leaf expansion of native grasses belonging to capture and conservation groups of resources dominant in a natural grassland. The experiment was conducted during 151 days from October 2015 to March 2016, and twenty-four Braford heifers tests mean age = 12 months; mean body weight = 220kg (± 27.8) were used. The pre-grazing total forage mass (FMt) was on average 3791 kgMSha-1 and did not differ between treatments and season, the same occurred with the non-tussock FM. The average stocking rate was 469 kg ha-1 in both treatments. The average daily gain varied only between seasons, 0.102 kg animal-1 day-1 during spring and 0.372 kg animal-1 day-1 during summer. During the 151 evaluation days, the gain per area was a 103 kgha-1. The use of rest intervals between grazing based on the leaf elongation of dominant grasses, when applied to the areas of Campos grasslands, provided nutritional conditions to reach the target body weight for breeding 24 months old beef heifers.

RESUMO: O estudo objetivou avaliar o efeito de dois intervalos de descanso entre pastoreios nas características estruturais do pasto e desempenho de novilhas de corte em pastagens naturais manejadas em pastejo rotativo. Os tratamentos foram dois intervalos entre pastejos de 375 e 750 GD (graus dia), baseados na soma térmica da duração de elongação foliar média de gramíneas de grupos de captura e conservação dos recursos dominantes de uma pastagem natural. O experimento foi conduzido no período de outubro de 2015 a março de 2016, com duração de 151 dias e os períodos experimentais divididos em primavera e verão. Foram utilizadas 24 novilhas teste da raça Braford, com idade inicial na média de 12 meses, e de peso corporal médio de 220 kg (± 27,8). A Massa de forragem total (FMt) pré-pastejo foi em média de 3791 kgMSha-1 e não diferiu entre tratamentos e estação, o mesmo ocorreu com a FM de estrato não touceira. A taxa de lotação média foi de 469 kgha-1 em ambos os tratamentos. O ganho médio diário variou apenas entre estações, com médias de 0,102 kganimal-1dia-1 na primavera e 0,372 kganimal-1dia-1 no verão. O ganho por área durante os 151 dias de avaliação foi em média de 103 kgha-1. As pastagens naturais submetidas a intervalos de descanso entre pastoreios baseados na elongação foliar de gramíneas dominantes, independente do tratamento utilizado, proporcionam ritmos de ganhos médios diários compatíveis com a meta de peso corporal, a ser atingida aos 24 meses, para que as novilhas possam ser acasaladas.

Description of a new myxozoan Kudoa eugerres n. sp. and reclassification of two Sphaerospora sensu lato species.

Ultrastructural and phylogenetic description of a fish-infecting myxosporean found infecting the gallbladder wall of the teleostean Eugerres brasilianus Cuvier, 1830, collected from the Atlantic coast near the city of Maceió (Alagoas State), Brazil. Groups of mature pseudo-conical myxospores, agglutinated forming pseudocyst structures, occurring in the mucosa of gallbladder were 5.2 ± 0.8 µm (4.5-6.0) (n = 30) long, 4.3 ± 0.6 µm (3.8-4.7) (n = 25) thick, and 2.9 ± 0.2 µm (2.7-3.2) (n = 25) wide. The two ellipsoidal polar capsules, 1.8 ± 0.4 × 1.2 ± 0.4 µm (n = 25), opened close to the sutural line, each containing an isofilar polar tubule. The latter consisted of a single coil with five to six turns, arranged obliquely to the axis of the polar capsule. This myxosporean parasite, while being morphologically similar to Sphaerospora spp., displays tissue tropism and phylogenetic relationships distinct from the latter. Bayesian inference (BI) and maximum likelihood (ML) analyses showed the parasite and two other related species clustering within the marine clade, more specifically within a subclade of the larger Kudoa (Multivalvulida) clade. Consequently, this atypical new myxozoan species was classified as Kudoa eugerres n. sp. and two other histozoic Sphaerospora spp. sensu lato were transferred to the genus Kudoa.

Ultrastructure of phagocytes and oocysts of Nematopsis sp. (Apicomplexa, Porosporidae) infecting Crassostrea rhizophorae in Northeastern Brazil.

This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.

Ultrastructure of phagocytes and oocysts of Nematopsis sp. (Apicomplexa, Porosporidae) infecting Crassostrea rhizophorae in Northeastern Brazil / Ultraestrutura de fagócitos e oocistos de Nematopsis sp. (Apicomplexa, Porosporidae) infectando Crassostrea rhizophorae no Nordeste brasileiro

Abstract This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis (Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.

Resumo Este trabalho descreve a morfologia ultraestrutural detalhada do fagócito encarcerando um oocisto de Nematopsis (Apicomplexa) encontrado em Crassostrea rhizophorae, na cidade de Maceió (AL), Brasil. Os hospedeiros muito infectados apresentavam valvas entreabertas com retração fraca e lenta dos músculos abdutores. Número variável de oócitos de forma elipsoide, isolados e ou agrupados foi encontrado entre as miofibrilas do músculo abdutor. Cada oocisto estava encarcerado num vacúolo parasitóforo do fagócito uninucleado do hospedeiro. Os oocistos eram compostos por uma parede densa contendo um esporozoíto vermiforme uninucleado. A parede dos oocistos finos era composta de material electron-lucente homogêneo formado por três camadas de espessura igual, possuindo um orifício circular - micrópila, obstruída pelo opérculo. Os oocistos apresentavam morfologia elipsoide, sua parede era circundada por uma complexa rede de numerosas microfibrilas. Detalhes de valor taxonômico importantes foram visualizados tais como: a organização ultraestrutural da parede do oocisto e a organização da micrópila e do opérculo, além das microfibrilas que se projetam da parede do oocisto, estrutura apenas observada em microscopia eletrônica de transmissão (MET) e que pode auxiliar na identificação da espécie. Contudo, para esclarecer a posição sistemática da maioria das espécies relatadas do gênero Nematopsis é importante prosseguir com as análises genéticas.

Ultrastructure of phagocytes and oocysts of Nematopsis sp. (Apicomplexa, Porosporidae) infecting Crassostrea rhizophorae in Northeastern Brazil / Ultraestrutura de fagócitos e oocistos de Nematopsis sp. (Apicomplexa, Porosporidae) infectando Crassostrea rhizophorae no Nordeste brasileiro

This work describes the detailed ultrastructural morphology of the phagocyte imprisoning an oyster of Nematopsis(Apicomplexa) found in Crassostrea rhizophorae, in the city of Maceió (AL), Brazil. The highly infected hosts had half-open leaflets with weak, slow retraction of the adductor muscles. Variable number of ellipsoid oocytes, either isolated and or clustered, was found between myofibrils of the adductor muscle. Each oocyst was incarcerated in a parasitophorous vacuole of host uninucleated phagocyte. The oocysts were composed of a dense wall containing a uninucleate vermiform sporozoite. The wall of the fine oocysts was composed of homogeneous electron-lucent material formed by three layers of equal thickness, having a circular orifice-micropyle obstructed by the operculum. The oocysts presented ellipsoid morphology with their wall was surrounded by a complex network of numerous microfibrils. Important details of the taxonomic value were visualized such as the ultrastructural organization of the oocyst wall and the organization of the micropyle and operculum, beyond the microfibrils that protrude from the oocyst wall only observed by transmission electron microscopy (TEM) and that may aid in the identification of the species. However, in order to clarify the systematic position of the species reported of the genus Nematopsis, it is important to proceed with genetic analyses.(AU)

Este trabalho descreve a morfologia ultraestrutural detalhada do fagócito encarcerando um oocisto de Nematopsis(Apicomplexa) encontrado em Crassostrea rhizophorae, na cidade de Maceió (AL), Brasil. Os hospedeiros muito infectados apresentavam valvas entreabertas com retração fraca e lenta dos músculos abdutores. Número variável de oócitos de forma elipsoide, isolados e ou agrupados foi encontrado entre as miofibrilas do músculo abdutor. Cada oocisto estava encarcerado num vacúolo parasitóforo do fagócito uninucleado do hospedeiro. Os oocistos eram compostos por uma parede densa contendo um esporozoíto vermiforme uninucleado. A parede dos oocistos finos era composta de material electron-lucente homogêneo formado por três camadas de espessura igual, possuindo um orifício circular - micrópila, obstruída pelo opérculo. Os oocistos apresentavam morfologia elipsoide, sua parede era circundada por uma complexa rede de numerosas microfibrilas. Detalhes de valor taxonômico importantes foram visualizados tais como: a organização ultraestrutural da parede do oocisto e a organização da micrópila e do opérculo, além das microfibrilas que se projetam da parede do oocisto, estrutura apenas observada em microscopia eletrônica de transmissão (MET) e que pode auxiliar na identificação da espécie. Contudo, para esclarecer a posição sistemática da maioria das espécies relatadas do gênero Nematopsis é importante prosseguir com as análises genéticas.(AU)

Biologia populacional da carapeba listrada, Eugerres brasilianus (Cuvier, 1830), próximo à foz do Rio São Francisco (Brasil) / Populational biology of Brazilian mojarra Eugerres brasilianus (Cuvier, 1830) next to the São Francisco River mouth (Brazil)

Eugerres brasilianus é uma das principais espécies de peixe comerciais no Nordeste do Brasil e no baixo rio São Francisco. O objetivo deste estudo foi avaliar a estrutura populacional da espécie na região. Os peixes foram coletados mensalmente com rede de emalhe, entre maio e dezembro de 2013. De 95 indivíduos capturados, 80% eram fêmeas com comprimento padrão oscilando entre as classes de 17,0 cm e 29,0 cm. A relação peso/comprimento em fêmeas e machos durante os períodos de chuva e estiagem evidenciou crescimento do tipo alométrico negativo. Os estágios de maturação gonadal variaram de B (em maturação) a C (maduro) para as fêmeas durante o período chuvoso, indicando atividade reprodutiva, fato confirmado pelo índice gonadossomático e pelo fator de condição (K), cujos valores foram superiores nas fêmeas (p>0,05). Os resultados indicam que o desenvolvimento da espécie pode estar relacionado ao período pré-reprodutivo, pois o crescimento em comprimento foi maior que em peso.

Eugerres brasilianus is one of the main marketable species in Northeastern Brazil and in the lower São Francisco River. The objective of this study was to evaluate the population structure of this species in the region. Fish were collected monthly through gillnet from May to December 2013. About 80% of 95 individuals captured were females ranging between the classes 17.0 - 29.0 cm of standard length. The weight/length ratio in females and males during the rainy and dry seasons presented a negative allometric type of growth. Gonadal maturation stages varied from B (under maturation) to C (mature) for females during the rainy season, indicating reproductive activity, a fact confirmed by the gonadosomatic index and the condition factor K, whose values were superior in females (p> 0.05). The results indicate that the species development may be related to the prereproductive period, because the growth in length was greater than in weight.

Biologia populacional da carapeba listrada, Eugerres brasilianus (Cuvier, 1830), próximo à foz do Rio São Francisco (Brasil) / Populational biology of Brazilian mojarra Eugerres brasilianus (Cuvier, 1830) next to the São Francisco River mouth (Brazil)

Eugerres brasilianus é uma das principais espécies de peixe comerciais no Nordeste do Brasil e no baixo rio São Francisco. O objetivo deste estudo foi avaliar a estrutura populacional da espécie na região. Os peixes foram coletados mensalmente com rede de emalhe, entre maio e dezembro de 2013. De 95 indivíduos capturados, 80% eram fêmeas com comprimento padrão oscilando entre as classes de 17,0 cm e 29,0 cm. A relação peso/comprimento em fêmeas e machos durante os períodos de chuva e estiagem evidenciou crescimento do tipo alométrico negativo. Os estágios de maturação gonadal variaram de B (em maturação) a C (maduro) para as fêmeas durante o período chuvoso, indicando atividade reprodutiva, fato confirmado pelo índice gonadossomático e pelo fator de condição (K), cujos valores foram superiores nas fêmeas (p>0,05). Os resultados indicam que o desenvolvimento da espécie pode estar relacionado ao período pré-reprodutivo, pois o crescimento em comprimento foi maior que em peso.(AU)

Eugerres brasilianus is one of the main marketable species in Northeastern Brazil and in the lower São Francisco River. The objective of this study was to evaluate the population structure of this species in the region. Fish were collected monthly through gillnet from May to December 2013. About 80% of 95 individuals captured were females ranging between the classes 17.0 - 29.0 cm of standard length. The weight/length ratio in females and males during the rainy and dry seasons presented a negative allometric type of growth. Gonadal maturation stages varied from B (under maturation) to C (mature) for females during the rainy season, indicating reproductive activity, a fact confirmed by the gonadosomatic index and the condition factor K, whose values were superior in females (p> 0.05). The results indicate that the species development may be related to the prereproductive period, because the growth in length was greater than in weight.(AU)