The neuroendocrine pathways and mechanisms for the control of the reproduction in female pigs

Abstract Within the hypothalamic-pituitary-gonad (HPG) axis, the major hierarchical component is gonadotropin-releasing hormone (GnRH) neurons, which directly or indirectly receive regulatory inputs from a wide array of regulatory signals and pathways, involving numerous circulating hormones, neuropeptides, and neurotransmitters, and which operate as a final output for the brain control of reproduction. In recent years, there has been an increasing interest in neuropeptides that have the potential to stimulate or inhibit GnRH in the hypothalamus of pigs. Among them, Kisspeptin is a key component in the precise regulation of GnRH neuron secretion activity. Besides, other neuropeptides, including neurokinin B (NKB), neuromedin B (NMB), neuromedin S (NMS), α-melanocyte-stimulating hormone (α-MSH), Phoenixin (PNX), show potential for having a stimulating effect on GnRH neurons. On the contrary, RFamide-related peptide-3 (RFRP-3), endogenous opioid peptides (EOP), neuropeptide Y (NPY), and Galanin (GAL) may play an inhibitory role in the regulation of porcine reproductive nerves and may directly or indirectly regulate GnRH neurons. By combining data from suitable model species and pigs, we aim to provide a comprehensive summary of our current understanding of the neuropeptides acting on GnRH neurons, with a particular focus on their central regulatory pathways and underlying molecular basis.

The neuroendocrine pathways and mechanisms for the control of the reproduction in female pigs

Within the hypothalamic-pituitary-gonad (HPG) axis, the major hierarchical component is gonadotropin-releasing hormone (GnRH) neurons, which directly or indirectly receive regulatory inputs from a wide array of regulatory signals and pathways, involving numerous circulating hormones, neuropeptides, and neurotransmitters, and which operate as a final output for the brain control of reproduction. In recent years, there has been an increasing interest in neuropeptides that have the potential to stimulate or inhibit GnRH in the hypothalamus of pigs. Among them, Kisspeptin is a key component in the precise regulation of GnRH neuron secretion activity. Besides, other neuropeptides, including neurokinin B (NKB), neuromedin B (NMB), neuromedin S (NMS), α-melanocyte-stimulating hormone (α-MSH), Phoenixin (PNX), show potential for having a stimulating effect on GnRH neurons. On the contrary, RFamide-related peptide-3 (RFRP-3), endogenous opioid peptides (EOP), neuropeptide Y (NPY), and Galanin (GAL) may play an inhibitory role in the regulation of porcine reproductive nerves and may directly or indirectly regulate GnRH neurons. By combining data from suitable model species and pigs, we aim to provide a comprehensive summary of our current understanding of the neuropeptides acting on GnRH neurons, with a particular focus on their central regulatory pathways and underlying molecular basis.(AU)

Electrocardiographic aspects of singleton pregnancy and neonatal period in American Miniature horse breed

Background: During pregnancy, cardiovascular adaptations occur in order to meet maternal demands and adequate supportfor fetal development, but they are still unclear in the equine species, especially in the American Miniature horse breed.The main hemodynamic changes that occur during pregnancy are increased heart rate, cardiac output, and blood volume.It is necessary to use the reference values for the miniature breeds, in addition to the age range and reproductive condition,so the objective of this study was to evaluate the effect of pregnancy on electrocardiographic (ECG) parameters in maresand also of age in newborns foals of American Miniature horse breed.Materials, Methods & Results: Ten American Miniature Horse mares, between 7 and 19 years old (12.14 ± 4.05 years),116.85 ± 24.09 kg of body weight were used in the experiment. All these mares were pluriparous, with 5.9 ± 3.5 of births,minimum of 2, and maximum of 12 foaling times. They were maintained in common social group in an indoor house stablewith straw bed, with access to an outdoor paddock for several h per day. Twice a day they were fed with hay. Mineral supplements and water were available ad libitum. The ECG were obtained in 10 pregnant mares and in 10 neonates. All femaleswere examined at a representative time of each trimester of pregnancy, at 30, 210, 300 days before and 21 days after delivery.Neonates were examined on different times: first 24 h after delivery, weekly on the 7th, 14th, 21st, 28th and 35th days of age.The ECG parameters considered were the heart rate and rhythm, duration and intervals (P, PR, QRS, QT, T) and amplitude(P, R, S, T) of ECG waves. The mean of pregnancy duration was 319.4 ± 4.97 days. Heart Rate (HR) varied between 51 to59 bpm during pregnancy and 56 bpm on the 21st day after delivery. Comparing the clinical parameters of pregnant mares,non-pregnant mares and foal a difference was found for HR, Respiration Rate (RR) and...

Electrocardiographic aspects of singleton pregnancy and neonatal period in American Miniature horse breed

Background: During pregnancy, cardiovascular adaptations occur in order to meet maternal demands and adequate supportfor fetal development, but they are still unclear in the equine species, especially in the American Miniature horse breed.The main hemodynamic changes that occur during pregnancy are increased heart rate, cardiac output, and blood volume.It is necessary to use the reference values for the miniature breeds, in addition to the age range and reproductive condition,so the objective of this study was to evaluate the effect of pregnancy on electrocardiographic (ECG) parameters in maresand also of age in newborns foals of American Miniature horse breed.Materials, Methods & Results: Ten American Miniature Horse mares, between 7 and 19 years old (12.14 ± 4.05 years),116.85 ± 24.09 kg of body weight were used in the experiment. All these mares were pluriparous, with 5.9 ± 3.5 of births,minimum of 2, and maximum of 12 foaling times. They were maintained in common social group in an indoor house stablewith straw bed, with access to an outdoor paddock for several h per day. Twice a day they were fed with hay. Mineral supplements and water were available ad libitum. The ECG were obtained in 10 pregnant mares and in 10 neonates. All femaleswere examined at a representative time of each trimester of pregnancy, at 30, 210, 300 days before and 21 days after delivery.Neonates were examined on different times: first 24 h after delivery, weekly on the 7th, 14th, 21st, 28th and 35th days of age.The ECG parameters considered were the heart rate and rhythm, duration and intervals (P, PR, QRS, QT, T) and amplitude(P, R, S, T) of ECG waves. The mean of pregnancy duration was 319.4 ± 4.97 days. Heart Rate (HR) varied between 51 to59 bpm during pregnancy and 56 bpm on the 21st day after delivery. Comparing the clinical parameters of pregnant mares,non-pregnant mares and foal a difference was found for HR, Respiration Rate (RR) and...(AU)

Boar seminal plasma: current insights on its potential role for assisted reproductive technologies in swine

Seminal plasma (SP) supports not only sperm function but also the ability of spermatozoa to withstand biotechnological procedures as artificial insemination, freezing or sex sorting. Moreover, evidence has been provided that SP contains identifiable molecules which can act as fertility biomarkers, and even improve the output of assisted reproductive technologies by acting as modulators of endometrial and embryonic changes of gene expression, thus affecting embryo development and fertility beyond the sperm horizon. In this overview, we discuss current knowledge of the composition of SP, mainly proteins and cytokines, and their influence on semen basic procedures, such as liquid storage or cryopreservation. The role of SP as modulator of endometrial and embryonic molecular changes that lead to successful pregnancy will also be discussed.

Boar seminal plasma: current insights on its potential role for assisted reproductive technologies in swine

Seminal plasma (SP) supports not only sperm function but also the ability of spermatozoa to withstand biotechnological procedures as artificial insemination, freezing or sex sorting. Moreover, evidence has been provided that SP contains identifiable molecules which can act as fertility biomarkers, and even improve the output of assisted reproductive technologies by acting as modulators of endometrial and embryonic changes of gene expression, thus affecting embryo development and fertility beyond the sperm horizon. In this overview, we discuss current knowledge of the composition of SP, mainly proteins and cytokines, and their influence on semen basic procedures, such as liquid storage or cryopreservation. The role of SP as modulator of endometrial and embryonic molecular changes that lead to successful pregnancy will also be discussed.(AU)

Cardiovascular evaluation in bitches in oestrus, pregnancy and puerperium

Background: Pregnancy may change maternal hemodynamic, which is considered a physiological mechanism for adaptation. Cardiac output tends to be influenced by reductions in vascular resistance and increases in uterine vasculature, as well as reduced autonomic tone combined with gestational physiological anaemia and increased blood volume due to increased plasma volume and hormonal mechanisms. In bitches, few studies have been conducted investigating the changes of the system and the clinical implications for the mother and foetuses due to poor cardiac adaptation during pregnancy.Materials, Methods & Results: Systolic blood pressure (SBP), electrocardiographic and Doppler echocardiographic measurements and serum sodium (Na), potassium (K), calcium (Ca) and phosphorus (P) levels were evaluated in six bitches of reproductive age. An evaluation was performed in oestrus (M0), followed by evaluations at 25 (M1), 45 (M2), and 60 days (M3) after the last natural or artificial insemination and 15 days after delivery (M4). For the statistical analysis, the means, medians and the standard deviation were calculated. The data were analysed using ANOVA and the Tukey test, with significance level of 5%. A descriptive analysis was performed for color Doppler in echocardiogram evaluation, cardiac axis and rhythm in electrocardiogram evaluation. In the electrolytic evaluation, significant differences were found only in the serum levels of Na, noticed as a reduction in M0-M1 and M3-M2 and an increase in M1-M2 and M3-M4. No significant differences were observed in the SBP, although there was a tendency to SBP reduction. ECG parameters were not significantly different, with no rhythm or conduction disturbances. There was not a significant difference in HR. Four animals (66.6%) had axis deviation to the right when comparing the oestrous phase with the final quarter of pregnancy. The echocardiographic parameters did not show significant changes.[...]

Cardiovascular evaluation in bitches in oestrus, pregnancy and puerperium

Background: Pregnancy may change maternal hemodynamic, which is considered a physiological mechanism for adaptation. Cardiac output tends to be influenced by reductions in vascular resistance and increases in uterine vasculature, as well as reduced autonomic tone combined with gestational physiological anaemia and increased blood volume due to increased plasma volume and hormonal mechanisms. In bitches, few studies have been conducted investigating the changes of the system and the clinical implications for the mother and foetuses due to poor cardiac adaptation during pregnancy.Materials, Methods & Results: Systolic blood pressure (SBP), electrocardiographic and Doppler echocardiographic measurements and serum sodium (Na), potassium (K), calcium (Ca) and phosphorus (P) levels were evaluated in six bitches of reproductive age. An evaluation was performed in oestrus (M0), followed by evaluations at 25 (M1), 45 (M2), and 60 days (M3) after the last natural or artificial insemination and 15 days after delivery (M4). For the statistical analysis, the means, medians and the standard deviation were calculated. The data were analysed using ANOVA and the Tukey test, with significance level of 5%. A descriptive analysis was performed for color Doppler in echocardiogram evaluation, cardiac axis and rhythm in electrocardiogram evaluation. In the electrolytic evaluation, significant differences were found only in the serum levels of Na, noticed as a reduction in M0-M1 and M3-M2 and an increase in M1-M2 and M3-M4. No significant differences were observed in the SBP, although there was a tendency to SBP reduction. ECG parameters were not significantly different, with no rhythm or conduction disturbances. There was not a significant difference in HR. Four animals (66.6%) had axis deviation to the right when comparing the oestrous phase with the final quarter of pregnancy. The echocardiographic parameters did not show significant changes.[...](AU)

Biometric testicular and serum testosterone concentration of Brazilian Ponies stallions / Biometria testicular e concentrações séricas de testosterona de garanhões Pôneis da raça Brasileira

Evaluation of the testis size is very important in stallions selection, since it is an indirect determinant of their reproductive potential. The aim of this study was to evaluate the biometric testicular traits, calculate the volume testicular and analyze the serum testosterone concentration of the stallion. During six months were measured the tests of adults Brazilian Ponies stallions from northern of Rio de Janeiro State, Brazil. The length, the width and the height of the testicles (TL, TW and TH) were measured. From these measurements, the total testicular volume (TTV) was calculated. The serum testosterone concentration was also evaluated. The data were studied by analysis of variance and were calculated the correlations among the traits. The average of the testis biometry were TL 5.8 ± 0.6 cm; TW 3.8 ± 0.5 cm; TH 4.7 ± 0.4 cm and 111.2 ± 27.7 for TTV. Mean of serum testosterone concentration was 0.89 ± 0.52 ng/dl. High correlations between biometry testicular traits with testicular volume were observed and low to moderate correlations were observed for testicular traits, testosterone and sperm output. The testis size could be an important trait that assists to the prediction of stallion's reproductive potential of the Brazilian ponies stallions. It is suggested that there would be no fluctuation in serum testosterone concentration in Brazilian ponies stallions that coult afect on its fertility.(AU)

Avaliação do tamanho dos testículos é muito importante na seleção de garanhões, uma vez que é um determinante indireto do seu potencial reprodutivo. O objetivo deste estudo foi avaliar as características de biometria testiculares, calcular o volume testicular e analisar a concentração sérica de testosterona de garanhões. Durante seis meses, foram medidos os testículos de garanhões Pôneis da raça Brasileiro adultos, criados no Norte do Estado do Rio de Janeiro, Brasil. O comprimento a largura e a altura dos testículo (TL, TW e TH) foram mensurados. A partir dessas medidas, calculou-se o volume testicular total (TTV). Os dados foram avaliados por análise de variância e foram calculadas as correlações entre as características. A média geral das características de biometria testicular e volume testicular foram: TL 5,8 ± 0,6 cm; TW 3,8 ± 0,5 cm; TH 4,7 ± 0,4 cm e TTV 111.2 ± 27,7. A média de concentração sérica de testosterona foi de 0,89 ± 0,52 ng/dl. Altas correlações foram observadas entre as características de biometria testicular e volume testicular. Baixas a médias correlações entre as características testiculares com produção espermática e com concentração de testosterona foram observadas. O tamanho testicular pode ser uma importante característica que auxilia na predição do potencial reprodutivo do garanhão pôneis da raça Brasileira. Sugere-se que não há variações na concentração sérica de testosterona nos pôneis da raça Brasileira que poderia afetar em sua fertilidade.(AU)

Biometric testicular and serum testosterone concentration of Brazilian Ponies stallions / Biometria testicular e concentrações séricas de testosterona de garanhões Pôneis da raça Brasileira

Evaluation of the testis size is very important in stallions’ selection, since it is an indirect determinant of their reproductive potential. The aim of this study was to evaluate the biometric testicular traits, calculate the volume testicular and analyze the serum testosterone concentration of the stallion. During six months were measured the tests of adults Brazilian Ponies stallions from northern of Rio de Janeiro State, Brazil. The length, the width and the height of the testicles (TL, TW and TH) were measured. From these measurements, the total testicular volume (TTV) was calculated. The serum testosterone concentration was also evaluated. The data were studied by analysis of variance and were calculated the correlations among the traits. The average of the testis biometry were TL 5.8 ± 0.6 cm; TW 3.8 ± 0.5 cm; TH 4.7 ± 0.4 cm and 111.2 ± 27.7 for TTV. Mean of serum testosterone concentration was 0.89 ± 0.52 ng/dl. High correlations between biometry testicular traits with testicular volume were observed and low to moderate correlations were observed for testicular traits, testosterone and sperm output. The testis size could be an important trait that assists to the prediction of stallion's reproductive potential of the Brazilian ponies stallions. It is suggested that there would be no fluctuation in serum testosterone concentration in Brazilian ponies stallions that coult afect on its fertility.

Avaliação do tamanho dos testículos é muito importante na seleção de garanhões, uma vez que é um determinante indireto do seu potencial reprodutivo. O objetivo deste estudo foi avaliar as características de biometria testiculares, calcular o volume testicular e analisar a concentração sérica de testosterona de garanhões. Durante seis meses, foram medidos os testículos de garanhões Pôneis da raça Brasileiro adultos, criados no Norte do Estado do Rio de Janeiro, Brasil. O comprimento a largura e a altura dos testículo (TL, TW e TH) foram mensurados. A partir dessas medidas, calculou-se o volume testicular total (TTV). Os dados foram avaliados por análise de variância e foram calculadas as correlações entre as características. A média geral das características de biometria testicular e volume testicular foram: TL 5,8 ± 0,6 cm; TW 3,8 ± 0,5 cm; TH 4,7 ± 0,4 cm e TTV 111.2 ± 27,7. A média de concentração sérica de testosterona foi de 0,89 ± 0,52 ng/dl. Altas correlações foram observadas entre as características de biometria testicular e volume testicular. Baixas a médias correlações entre as características testiculares com produção espermática e com concentração de testosterona foram observadas. O tamanho testicular pode ser uma importante característica que auxilia na predição do potencial reprodutivo do garanhão pôneis da raça Brasileira. Sugere-se que não há variações na concentração sérica de testosterona nos pôneis da raça Brasileira que poderia afetar em sua fertilidade.

Effect of supplementation frequency in feeding behavior, displacement patterns and forage intake of beef heifers / Efeito de frequências de suplementação no comportamento ingestivo, padrões de deslocamento e ingestão de forragem por novilhas de corte

Our work was carried out to evaluate forage intake, feeding behavior and displacement patterns of beef heifers fed exclusively on pasture or receiving oat grain, either daily (frequent) or from Monday to Friday (infrequent), in two phenological stages of Alexandergrass (Urochloa plantaginea Link.): Vegetative and Reproductive. The grazing method was continuous, with a variable number of animals. The experimental design was completely randomized with measures repeated in time with three feeding frequencies and two phenological stages. Forage intake was estimated using the chromic oxide technique as an indicator of fecal output. Heifers on exclusive Alexandergrass pasture and frequently supplemented had higher forage intake of dry matter (DM, 2.91 kg DM 100 kg BW-1) than those that were infrequently supplemented (2.00 kg DM 100 kg BW-1). Forage intake was greater in the Vegetative stage. The use of feeding stations is modified in response to supplementation frequency and phenological stages of Alexandergrass. Bite mass was higher for daily supplemented heifers, and these animals spent less time grazing. Also, bite mass was the item that best explained DM total ingestion. Bite mass and grazing time were similar throughout the phenological stages, whereas bite rate decreased in the reproductive stage. Feeding behavior and forage intake responses of beef heifers were influencedby supplementation frequency and phenological stages of Alexandergrass.(AU)

Nos estádios fenológicos Vegetativo e Reprodutivo do papuã (Urochloa plantaginea Link.) foram avaliados a ingestão de matéria seca, o comportamento ingestivo e os padrões de deslocamento de novilhas em pastejo ou recebendo grão de aveia diariamente (frequente) ou de segunda a sexta-feira (infrequente). O método de pastejo foi contínuo com número variável de animais. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo com três frequências alimentares e dois estádios fenológicos. A ingestão de matéria seca foi estimada por meio de técnica do óxido de cromo como indicador da produção fecal. Animais em pastagem exclusiva de papuã e com suplemento diário consumiram mais forragem (2,91 kg MS 100 kg PC-1) que os animais que receberam suplemento infrequente (2,00 kg MS 100 kg PC-1). O consumo de forragem foi maior no estádio Vegetativo do que no Reprodutivo. O uso das estações alimentares é modificado em resposta as frequências de suplementação e estádios fenológicos. Novilhas que receberam suplemento diariamente pastejaram por menor tempo e colheram bocados mais pesados. A massa de bocado é o item que melhor explica a ingestão total de MS. O peso do bocado e o tempo de pastejo foram semelhantes nos estádios fenológicos do pasto enquanto a taxa de bocado diminuiu no estádio reprodutivo. Mudanças na frequência de suplementação e nos estádios fenológicos do papuã modificam o comportamentoingestivo e o consumo de forragem de novilhas de corte.(AU)

FOLHAS DE MORINGA OLEIFERA E ENZIMAS EXÓGENAS EM DIETAS DE GALINHAS POEDEIRAS

Objetivou-se estudar o efeito da inclusão de farelo de folhas de Moringa oleífera em dietas suplementadas com enzimas exógenas sobre o desempenho, qualidade de ovos, bioquímica sérica, órgãos do sistema digestório, reprodutor e glândulas anexas, assim como verificar possíveis influências destes sobre a morfometria intestinal de galinhas poedeiras na idade de pico de postura. Foram utilizadas 288 aves de postura da linhagem Dekalb White com 32 semanas de idade distribuídas em um delineamento inteiramente casualizado em arranjo fatorial 2 x 4 (presença e ausência de farinha de folhas de Moringa oleífera x 4 formas de suplementação enzimática) totalizando oito tratamentos com seis repetições de seis aves por unidade experimental. Os tratamentos consistiram em uma dieta controle, a base de milho e farelo de soja, e uma dieta com suplementação de 5% de farinha de folhas de moringa seguida de três formas de suplementação enzimática (xilanase, fitase e mix das duas enzimas). A associação enzimática nas dietas com FMO influenciou positivamente a produção, peso e massa de ovos. O consumo foi superior nas suplementações com xilanase quando comparada as outras dietas. A moringa aumentou significativamente a altura de albúmen e a unidade Haugh, enquanto a espessura da casca e escore de ovoscopia foram melhorados na presença da FMO e fitase. O FMO proporcionou intensificação da cor das gemas dos ovos e diminuiu as concentrações plasmáticas de colesterol e LDL dos animais. Concluiu-se que o FMO ao nível de 5% não compromete o desempenho de galinhas poedeiras e que a suplementação enzimática, isolada ou em associação com FMO nas dietas podem melhorar o peso dos ovos. A xilanase, sozinha ou associada com a fitase, teve um papel importante na diminuição do tamanho relativo do intestino delgado e cecos, assim como proporcionou melhorias na morfologia intestinal através do aumento da altura de vilosidades, profundidade de criptas, relação altura de vilosidades:profundidade de criptas, comprimento de mucosa e largura das vilosidades, caracterizando assim, melhorias nos processos de digestão e absorção de nutrientes. Conclui-se que os PNAs presentes no FMO exercem diversos efeitos no intestino, tais como aumento do tamanho do intestino e glândulas anexas, além de influenciarem as características morfométricas intestinais. Logo, FMO tem o potencial de aumentar a intensidade da cor das gemas e sua associação com a enzima fitase melhora a qualidade da casca. Os PNAs presentes no FMO exercem diversos efeitos no intestino, tais como aumento do tamanho do intestino e glândulas anexas além de influenciarem as características morfométricas intestinais. A ação da xilanase, com degradação desses nutrientes, parece reestabelecer a saúde intestinal das aves o que pode levar a melhor desempenho das poedeiras.

The objective was to study the effect of including Moringa oleifera leaf meal in diets supplemented with exogenous enzymes on performance, egg quality, serum biochemistry, digestive and reproductive system organs and attached glands, as well as to verify possible influences of these on the intestinal morphometry of laying hens at peak laying period. A total of 288 laying hens of the 32-week-old Dekalb White lineage were distributed in a completely randomized design in a 2 x 4 factorial arrangement (presence and absence of Moringa oleifera leaf flour x 4 forms of enzymatic supplementation) totaling eight treatments with six replicates of six birds per experimental unit. The treatments consisted of a control diet, based on corn and soybean meal, and a diet supplemented with 5% moringa leaf flour followed by three forms of enzymatic supplementation (xylanase, phytase and a mix of the two enzymes). The enzymatic association in diets with OMF positively influenced egg output, weight and egg mass. Laying hens fed xylanase supplemented diet had higher feed intake than those fed other diets. Moringa significantly increased albumen height and Haugh unit, while shell thickness and candling score were improved in the presence of FMO and phytase. FMO enhanced the egg color yolks and decreased the plasma concentrations of cholesterol and LDL. It was concluded that FMO at the 5% level does not compromise the performance of laying hens and that enzyme supplementation, alone or in association with FMO in the diets, can improve egg weight. Xylanase, alone or associated with phytase, played an important role in decreasing the relative size of the small intestine and cecum, as well as providing improvements in intestinal morphology through increased villous height, crypt depth, villous height:depth ratio of crypts, mucosal length and villi width, thus characterizing improvements in the processes of digestion and absorption of nutrients. It is concluded that the PNAs present in the FMO exert several effects on the intestine, such as increasing the size of the intestine and adnexal glands, in addition to influencing the intestinal morphometric characteristics. Therefore, FMO has the potential to increase the color intensity of yolks and its association with the enzyme phytase improves the quality of the shell. The PNAs present in FMO exert several effects on the intestine, such as increasing the size of the intestine and adnexal glands, in addition to influencing the intestinal morphometric characteristics. The action of xylanase, with degradation of these nutrients, seems to restore the intestinal health of the birds, which can lead to better performance in laying hens.

Avaliação cardiorrespiratória dos efeitos da anestesia inalatória em capivaras (Hydrocoaerus hydrochaeris) submetidas à cirurgia contraceptiva pela técnica convencional e videocirurgia

A capivara é um roedor, hospedeiro do carrapato-estrela (Amblyomma cayennensis) e potencial disseminador da Febre Maculosa Brasileira. Por se adaptar facilmente a diversos ambientes e possuir alta capacidade reprodutiva, o controle populacional de alguns grupos de capivara pode se fazer necessário, sendo que os métodos mais adequados, considerando-se as características hierárquicas da espécie e a patogenia da febre maculosa, são a vasectomia e ligadura tubária. Sabendo-se das dificuldades na manutenção anestésica, da falta de literatura relacionada à anestesia nessa espécie e que as técnicas videolaparocópicas geralmente apresentam vantagens sobre as correspondentes abertas convencionais, objetiva-se avaliar a utilização da anestesia inalatória para os procedimentos de salpingectomia e deferentectomia em capivaras submetidas a duas diferentes abordagens pela técnica convencional e por videocirurgia. Foi realizado um estudo piloto com 32 animais capturados com peso médio de 53,9 ± 10,97 kg (32,3 - 69 kg). Todos os animais apresentaram instabilidade respiratória durante o procedimento cirúrgico, com valores de CO2 expirado chegando a 68 mmHg (62 ± 5 mmHg). Não houve necessidade de intervenção medicamentosa durante o procedimento cirúrgico, já que os animais apresentaram grau de relaxamento muscular e antinociceptivo satisfatórios com manutenção no isofluorano. Todos os animais apresentaram acúmulo de conteúdo gasoso intestinal, sendo necessária a canulação do ceco para diminuir a pressão abdominal, o qual foi tratado após introdução de cateter nº16. Em relação ao estudo experimental, 16 capivaras foram contidas quimicamente com a associação de cetamina (6,8 ± 1,6 mg/kg) com dexmedetomidina (7,9 ± 2 mcg/kg) e mantidas com isofluorano associado ou não a fármacos analgésicos. Foram avaliadas as variáveis de frequência cardíaca (FC) e ritmos cardíacos, pressão arterial sistólica, média e diastólica (PAS, PAM e PAD), temperatura retal, frequência respiratória (f), a tensão de dióxido no final da expiração (ETCO2 - mmHg) bem como as concentrações inspiradas e expiradas de isofluorano, a saturação da oxihemoglobina no sangue periférico (SpO2) nos momentos Basal, Incisão de Pele, Tracionamento, Sutura e Final. Foram coletadas amostras de sangue arterial no momento após a captura, anterior a oxigenação, anterior a intubação e ao término do procedimento cirúrgico, para obtenção dos valores de potencial hidrogeniônico no sangue arterial (pH), pressão parcial de dióxido de carbono no sangue arterial (PaCO2 - mmHg), pressão parcial de oxigênio no sangue arterial (PaO2 - mmHg), concentração plasmática de íon bicarbonato (HCO3 - - mmol/L), déficit de base (BE - mmol/L) e níveis séricos de lactato. O protocolo de contenção química proposto permitiu grau de relaxamento e sedação satisfatórios, permitindo coleta de amostras sanguíneas e paramentação dos animais para os procedimentos cirúrgico e anestésico. Em relação ao procedimento cirúrgico, a técnica convencional interferiu menos na dinâmica anestésica, apesar de não haverem diferenças significativas entre os parâmetros hemogasométricos, PAS, PAM, PAD, fração expirada de isofluorano e débito cardíaco, o monitoramento e a necessidade de diminuir a pressão intra-abdominal se fez necessário. Houve diferença principalmente em relação à frequência respiratória, e os animais do grupo Vídeo requereram maior necessidade de ventilação mecânica (P = 0,01328). Também não houve diferença entre os grupos em relação ao requerimento de fentanil. Com os dados obtidos, foi possível observar a importância da utilização de anestesia inalatória para a espécie em procedimentos invasivos de longa duração, permitindo maior estabilidade durante o período trans-cirúrgico sem a necessidade de reaplicação farmacológica.

Capybara is a rodent, host of the tick (Amblyomma cayennensis) and potential disseminator of Brazilian Macular Fever. By adapting easily to diverse environments and having a high reproductive capacity, the population control of some groups of capybara may be necessary, and the most appropriate methods, considering the hierarchical characteristics of the species and the pathogenesis of spotted fever, are the vasectomy and tubal ligation. Difficulties in anesthesia maintenance, the lack of literature related to anesthesia in this species and the fact that video-surgical techniques generally have advantages over the conventional open correspondents, the objective is to evaluate the use of inhalation anesthesia for salpingectomy and deferentectomy procedures in capybaras submitted to two different approaches by conventional technique and video-surgery. A pilot study was carried out with 32 animals captured with an average weight of 53.9 ± 10.97 kg (32.3 - 69 kg). All animals presented respiratory instability during the surgical procedure, with values of CO2 expired reaching 68 mmHg (62 ± 5 mmHg). There was no need for medication intervention during the surgical procedure, since all patients presented satisfactory muscular and antinociceptive relaxation with maintenance of isoflurane. All animals had an accumulation of intestinal gaseous contents and the cannulation of the cecum was necessary to reduce abdominal pressure which was treated after the introduction of catheter # 16. Regarding the experimental study, 16 capybaras were chemically contained with the association of ketamine (6.8 ± 1.6 mg/kg) with dexmedetomidine (7.9 ± 2 mcg/kg) and maintained with isoflurane associated or not with analgesic drugs. Heart rate (HR) and heart rate, systolic blood pressure (SBP), rectal temperature, respiratory rate (f), end-expired dioxide tension (ETCO2 - mmHg) as well as inspiratory and expired concentrations of isoflurane and the inspired fraction of oxygen (FIO2 -%), oxyhemoglobin saturation in the peripheral blood (SpO2) at Basal, Skin Incision, Traction, Suture and Final moments. Samples of arterial blood will be collected at the moment after intubation and at the end of the surgical procedure, in order to obtain the values of arterial hydrogenation potential (pH), arterial carbon dioxide partial pressure (PaCO2 - mmHg), partial pressure of arterial blood oxygen concentration (PaO2 - mmHg), plasma bicarbonate ion concentration (HCO3 - mmol / L), and baseline (BE - mmol / L) deficits. The proposed chemical restraint protocol allowed a satisfactory degree of relaxation and sedation, allowing the collection of blood samples and the preparation of the animals for surgical and anesthetic procedures. Regarding the surgical procedure, the conventional technique interfered less in the anesthetic dynamics, although there were no significant differences between the hemogasometric parameters, SBP, MAP, DBP, expired fraction of isoflurane and cardiac output, monitoring and the need to reduce intraabdominal pressure. There was a difference mainly regarding respiratory rate, and the animals in the Video group required greater need for mechanical ventilation (P = 0.01328). There was also no difference between groups regarding the requirement for fentanyl. With the data obtained, it was possible to observe the importance of using inhalation anesthesia for the species in long-term invasive procedures, allowing greater stability during the trans-surgical period without the need for pharmacological reapplication.

Great unexpected differences between two populations of the intertidal crab Neohelice granulata inhabiting close but contrasting habitats (Crustacea: Decapoda: Brachyura)

Two populations of the Southwestern Atlantic burrowing crab, Neohelice granulata (Dana, 1851), are separated by only 190 km. They inhabit bays that drain into a Patagonian gulf in the southernmost limit of the geographical distribution of the species: San Antonio Bay (SAO) and San José Gulf (RSJ). The population from SAO has been extensively studied, whereas that of RSJ has not. The main goal of this study is to compare the ecological and habitat characteristics of the two populations, based on samples collected on successive days during the middle of the reproductive season of the crab. The substrate of SAO is composed of a high proportion of gravel and scarce organic matter, whereas the substrate of RSJ presents twice as much silt and clay, and greater organic matter content. Crabs of both sexes were larger at RSJ. Fecundity and reproductive output were greater at RSJ. The size of females at maturity was smaller and their range was shorter at RSJ. Burrows were longer and wider at RSJ. Our results indicate that there are strong differences between the two populations, which might be correlated with local environmental differences, mainly substrate granulometry and food availability.

Great unexpected differences between two populations of the intertidal crab Neohelice granulata inhabiting close but contrasting habitats (Crustacea: Decapoda: Brachyura)

Two populations of the Southwestern Atlantic burrowing crab, Neohelice granulata (Dana, 1851), are separated by only 190 km. They inhabit bays that drain into a Patagonian gulf in the southernmost limit of the geographical distribution of the species: San Antonio Bay (SAO) and San José Gulf (RSJ). The population from SAO has been extensively studied, whereas that of RSJ has not. The main goal of this study is to compare the ecological and habitat characteristics of the two populations, based on samples collected on successive days during the middle of the reproductive season of the crab. The substrate of SAO is composed of a high proportion of gravel and scarce organic matter, whereas the substrate of RSJ presents twice as much silt and clay, and greater organic matter content. Crabs of both sexes were larger at RSJ. Fecundity and reproductive output were greater at RSJ. The size of females at maturity was smaller and their range was shorter at RSJ. Burrows were longer and wider at RSJ. Our results indicate that there are strong differences between the two populations, which might be correlated with local environmental differences, mainly substrate granulometry and food availability.(AU)

Reproductive biology of Macrobrachium surinamicum (Decapoda: Palaemonidae) in the Amazon River mouth / Biologia reprodutiva do camarão Macrobrachium surinamicum (Decapoda: Palaemonidae) na foz do rio Amazonas

Macrobrachium surinamicum is an indigenous prawn distributed from the lower Amazon and Tocantins river basins to Venezuela in the Orinoco Delta region. It is common bycatch fauna of Macrobrachium amazonicum artisan fishing in the states of Pará and Amapá. The aim of this study was to investigate aspects on reproductive biology (reproductive period, size of sexual maturity population, fecundity, reproductive output and recruitment) of M. surinamicum from four important areas to artisanal prawn fishing located at the Amazon River mouth (Amapá and Pará). The specimens were captured using 20 handcrafted traps called "matapi". A number of 675 prawns were captured, 258 males, 409 females and eight juveniles, resulting in 1:1.6 (Male: Female) sex ratio. The reproductive peak period occurred from March to July, coinciding with the higher rainfall period. The juvenile prawn occurred only in May and July. Total length of egg-bearing females ranged from 12.12 to 38.30 mm, with mean female length at first maturity (L50) of 23.7 mm. Fecundity increased with prawn size and varied between 174 and 1780 eggs per female. Mean egg volume increased gradually from 0.031 (Stage I) to 0.060 mm³ (Stage III) during embryogenesis. Macrobrachium surinamicum depends on brackish water to complete the larval development. Irrespective of female size, reproductive output of M. surinamicum varied between 4.3 % and 35.5 % of their body weight for egg production. The knowledge of the reproductive biology reported in the present study is an important tool to define strategies to preserve M. surinamicum in Amazon River mouth.(AU)

Macrobrachium surinamicum é uma espécie nativa de camarão de água doce distribuída do Brasil, nas bacias do rio Amazonas e Tocantins até a Venezuela na região do Delta do Orinoco. Este é fauna acompanhante comum da pesca artesanal de Macrobrachium amazonicum nos estados do Pará e Amapá. O objetivo deste trabalho foi abordar aspectos gerais da biologia reprodutiva (período reprodutivo, tamanho de primeira maturação, fecundidade, investimento reprodutivo e recrutamento) de M. surinamicum de quatro importantes áreas de pesca artesanal de camarão localizada na foz do rio Amazonas (Amapá e Pará). Os exemplares foram capturados usando 20 armadilhas artesanais, conhecidas localmente como matapi. Um total de 675 camarões foi capturado, 258 machos, 409 fêmeas e oito juvenis, resultando uma razão sexual geral de 1: 1,6 (macho:fêmea). Os picos reprodutivos ocorreram de março a julho, coincidindo com o período mais chuvoso. Os jovens foram observados em maio e julho. O comprimento total das fêmeas ovígeras variou de 12,12 a 38,30 mm, com o comprimento de primeira maturação (L50) estimado em 23,7 mm. A fecundidade aumentou com o tamanho das fêmeas, variando entre 174 e 1780 ovos por espécime. Volume médio dos ovos aumentou gradualmente durante a embriogênese saindo de 0,031 (Estágio I) para 0,060mm³ (Estágio III). Macrobrachium surinamicum dependem de água salobra para completar seu desenvolvimento larval. Independentemente do tamanho da fêmea, o investimento reprodutivo de M. surinamicumvariou entre 4,3 % e 35,5% do seu peso corporal para a produção de ovos. O conhecimento da biologia reprodutiva relatada no presente estudo é uma ferramenta importante para ajudar a definir estratégias para preservar M. surinamicum na foz do Rio Amazonas.(AU)

Reproductive biology of Macrobrachium surinamicum (Decapoda: Palaemonidae) in the Amazon River mouth / Biologia reprodutiva do camarão Macrobrachium surinamicum (Decapoda: Palaemonidae) na foz do rio Amazonas

Macrobrachium surinamicum is an indigenous prawn distributed from the lower Amazon and Tocantins river basins to Venezuela in the Orinoco Delta region. It is common bycatch fauna of Macrobrachium amazonicum artisan fishing in the states of Pará and Amapá. The aim of this study was to investigate aspects on reproductive biology (reproductive period, size of sexual maturity population, fecundity, reproductive output and recruitment) of M. surinamicum from four important areas to artisanal prawn fishing located at the Amazon River mouth (Amapá and Pará). The specimens were captured using 20 handcrafted traps called "matapi". A number of 675 prawns were captured, 258 males, 409 females and eight juveniles, resulting in 1:1.6 (Male: Female) sex ratio. The reproductive peak period occurred from March to July, coinciding with the higher rainfall period. The juvenile prawn occurred only in May and July. Total length of egg-bearing females ranged from 12.12 to 38.30 mm, with mean female length at first maturity (L50) of 23.7 mm. Fecundity increased with prawn size and varied between 174 and 1780 eggs per female. Mean egg volume increased gradually from 0.031 (Stage I) to 0.060 mm³ (Stage III) during embryogenesis. Macrobrachium surinamicum depends on brackish water to complete the larval development. Irrespective of female size, reproductive output of M. surinamicum varied between 4.3 % and 35.5 % of their body weight for egg production. The knowledge of the reproductive biology reported in the present study is an important tool to define strategies to preserve M. surinamicum in Amazon River mouth.

Macrobrachium surinamicum é uma espécie nativa de camarão de água doce distribuída do Brasil, nas bacias do rio Amazonas e Tocantins até a Venezuela na região do Delta do Orinoco. Este é fauna acompanhante comum da pesca artesanal de Macrobrachium amazonicum nos estados do Pará e Amapá. O objetivo deste trabalho foi abordar aspectos gerais da biologia reprodutiva (período reprodutivo, tamanho de primeira maturação, fecundidade, investimento reprodutivo e recrutamento) de M. surinamicum de quatro importantes áreas de pesca artesanal de camarão localizada na foz do rio Amazonas (Amapá e Pará). Os exemplares foram capturados usando 20 armadilhas artesanais, conhecidas localmente como matapi. Um total de 675 camarões foi capturado, 258 machos, 409 fêmeas e oito juvenis, resultando uma razão sexual geral de 1: 1,6 (macho:fêmea). Os picos reprodutivos ocorreram de março a julho, coincidindo com o período mais chuvoso. Os jovens foram observados em maio e julho. O comprimento total das fêmeas ovígeras variou de 12,12 a 38,30 mm, com o comprimento de primeira maturação (L50) estimado em 23,7 mm. A fecundidade aumentou com o tamanho das fêmeas, variando entre 174 e 1780 ovos por espécime. Volume médio dos ovos aumentou gradualmente durante a embriogênese saindo de 0,031 (Estágio I) para 0,060mm³ (Estágio III). Macrobrachium surinamicum dependem de água salobra para completar seu desenvolvimento larval. Independentemente do tamanho da fêmea, o investimento reprodutivo de M. surinamicumvariou entre 4,3 % e 35,5% do seu peso corporal para a produção de ovos. O conhecimento da biologia reprodutiva relatada no presente estudo é uma ferramenta importante para ajudar a definir estratégias para preservar M. surinamicum na foz do Rio Amazonas.

DESENVOLVIMENTO DE SENSOR ELETRÔNICO DE DETECÇÃO DE ESTRO E FREQUÊNCIA DE MONTA EM BOVINOS

A eficiência na pecuária leiteira e de corte é fundamental para que se tenha rentabilidade. Para tanto o manejo reprodutivo é importante para a obtenção de desempenho e produtividade. A eficiência na detecção de estro em programas de IA (inseminação artificial) ou mesmo na IATF (IA em tempo fixo) é necessária para alcançar resultados satisfatórios, tanto nas vacas de corte quanto de leite. Nestas últimas, as manifestações de estro são mais discretas ou imperceptíveis em vacas de alta produção de leite sujeitas a condições de estresse térmico. Enquanto vacas de raças Bos indicus apresentam normalmente cios de menor duração e maior frequência no período noturno, dificultando sua identificação. Como consequência, a baixa eficiência na detecção de estro causa redução na taxa de concepção e aumento do período de serviço. A maioria das técnicas e dispositivos disponíveis para detecção de estro necessitam do emprego de mão de obra para a obtenção de resultados positivos ou apresentam alto custo de implantação, além da ocorrência de falsos positivos ou mesmo falhas na detecção. Diante da importância da detecção de estro para a produção na pecuária e das dificuldades apresentadas, o presente estudo traz o desenvolvimento de um dispositivo eletrônico, com custo inferior às técnicas disponíveis no mercado, capaz de detectar o estro de forma precisa, com registro de data, hora e frequência das montas. Foram utilizadas plataformas microcontroladas de baixo custo, com sistema sleep que permite colocar o microcontrolador em estado de hibernação, reduzindo o consumo de energia. A plataforma microcontrolada escolhida foi a ESP8266 d1 mini, incorpora além do processamento de alto desempenho, memória de 4Mb, wireless e bluetooth, com dimensões extremamente reduzidas. Para detectar a monta no animal, escolheu-se o sensor piezoelétrico, que ao sofrer pressão mecânica de no mínimo 2 segundos, gera um sinal elétrico, sua saída foi ligada à entrada analógica do ESP8266, capaz de medir a intensidade do sinal gerado pelo sensor. Inicialmente para verificar eficiência do equipamento, um LED foi ligado à saída digital do ESP8266 e um programa em linguagem C foi escrito para acender o LED quando o ESP8266 detectar a variação de energia em sua entrada. Posteriormente, um novo programa foi escrito para gravar no cartão de memória SD Card as montas realizadas, bem como sua duração e o horário que ocorreu. Testes realizados em laboratório foram satisfatórios, comprovando que os componentes poderão viabilizar a comercialização de um equipamento de baixo custo, extremamente preciso e capaz de detectar o estro nas fêmeas domésticas.

The dairy and beef cattle livestock efficiency are fundamental for profitability. Thus, reproductive management is important to obtain productivity and performance. The efficiency in estrous detection in AI (artificial insemination) programs or even in TAI (timed artificial insemination) is necessary to achieve satisfactory results as in beef or in dairy cattle, which has a more discreet estrous manifestation or imperceptible estrous specially in high production dairy cattle, under heat stress. While cattle from Bos indicus breed are normally characterized by short duration estrous and high frequency occurring at night period, indeed presenting more difficulty to identify estrous. Consequently, low estrous detection efficiency leads to conception rates reduction and prolonged service period. The majority of techniques and devices for estrous detection need human labor to show positive results and present a high implantation cost. In addition, it has to be considered possible false positive or fail detection. Upon estrous detection importance for livestock production, and considering the present difficulties, the study propose the development of an electronic device, with a lower cost compared to what it is available, able to detects estrous precisely, registering date, hour and frequency of cattle mounting. Thus, it was used a low cost microcontrolled platform, using a sleep system, leading to hibernation and reduced consumption. The microcontrolled platform ESP8266 d1 mini, incorporates high performance processor, 4 Mb memory, wireless and bluetooth systems, with extremely reduced dimensions. A piezoelectric sensor was selected for animal mount detection, which under 2 seconds mechanic pressure at least generates an electric signal, thus its output was connected to an analog input from ESP8266, which was capable to measure intensity of sensor sign. To verify the equipment efficiency, the LED was connected to a digital output from ESP8266 and a language C program was written to light up the LED when the ESP8266 was capable to detect energy variation at its input. Laboratory tests were satisfactory, proving the compounds viability to commercialization of low cost equipment, extremely precise and capable to detect estrous in cattle.

Reproductive aspects of Macrobrachium amazonicum (Decapoda: Palaemonidae) in the State of Amapá, Amazon River mouth / Aspectos reprodutivos do camarão Macrobrachium amazonicum (Decapoda: Palaemonidae) no estado do Amapá, foz do rio Amazonas

Macrobrachium amazonicum is an indigenous prawn vastly distributed in basins of South America, widely exploited by artisanal fisheries in northern and northeastern Brazil and, with great potential for aquaculture. This study aimed to investigate general aspects of population structure and reproductive characteristics (size at first maturity, fecundity and reproductive output) of M. amazonicum from two important areas to artisanal prawn fishing located at the mouth of the Amazon River, State of Amapá. The specimens were captured using 20 handcrafted traps called "matapi". A number of 5,179 prawns were captured, 2,975 females and 2,195 males resulting in 1.35:1 female to male ratio. Santana Island and Mazagão Velho showed females predominated in the population. A reproductive peak period was observed from January to April/2009 and in December/2010, coinciding with the period of higher rainfall. The recruitment peak occurred in June and July/2009. Egg-bearing females ranged in size (carapace length) from 11.10 to 29.6 mm. Fecundity increased with female size and reached up to 7,417 eggs. This amount of eggs is considered low if compared with other Macrobrachium estuarine species. Mean egg volume increased gradually from 0.121 to 0.24 mm³ during embryogenesis, representing 68.5% of overall increase from Stage I to Stage III. Eggs of M. amazonicum are small; this is typical for Macrobrachium species, which depends on brackish water to complete the larval development. Irrespective of female size, reproductive output of M. amazonicum varied between 4.8 and 21.85% of their body weight into eggs production.

Macrobrachium amazonicum é uma espécie nativa vastamente distribuída nas bacias da America do Sul, sendo largamente explorada por pescadores artesanais no Norte e Nordeste do Brasil e com grande potencial para aquicultura. O objetivo deste trabalho foi abordar aspectos gerais da estrutura populacional e biologia reprodutiva (tamanho de primeira maturação, fecundidade e investimento reprodutivo) de M. amazonicum de duas importantes áreas de pesca artesanal de camarão localizada na foz do rio Amazonas, no Estado do Amapá. Os exemplares foram capturados usando 20 armadilhas artesanais, conhecidas localmente como matapi. Um total de 5.179 camarões foi capturado, dos quais 2.975 eram fêmeas e 2.195 eram machos, dando uma razão sexual geral de 1,35: 1 em favor das fêmeas. As proporções sexuais nas áreas de Ilha de Santana e Mazagão mostraram fêmeas predominando na população. Os picos reprodutivos nas duas áreas ocorreram de Janeiro a Abril/2009 e em Dezembro/2010, coincidindo com o período mais chuvoso. Os picos de recrutamento foram observados em junho e julho de 2009. O tamanho das fêmeas ovígeras variou de 11,10 mm a 29,6 mm de comprimento de carapaça. A fecundidade aumentou com o tamanho das fêmeas, chegando até 7.417 ovos, podendo ser considerada baixa comparada a outras espécies estuarinas de Macrobrachium. Volume médio dos ovos aumentou gradualmente durante a embriogênese saindo de 0,112 para 0,220 mm³, representando um aumento global de 68,5% do I ao III estágio embrionário. Os ovos de M. amazonicum podem ser considerados pequenos, típicos de espécies de Macrobrachium que dependem de água salgada para completar seu desenvolvimento larval. Independente do tamanho da fêmea, o investimento reprodutivo de M. amazonicum variou entre 4,8 e 21,85% do seu peso corporal para a produção de ovos.

Reproductive aspects of Macrobrachium amazonicum (Decapoda: Palaemonidae) in the State of Amapá, Amazon River mouth / Aspectos reprodutivos do camarão Macrobrachium amazonicum (Decapoda: Palaemonidae) no estado do Amapá, foz do rio Amazonas

Macrobrachium amazonicum is an indigenous prawn vastly distributed in basins of South America, widely exploited by artisanal fisheries in northern and northeastern Brazil and, with great potential for aquaculture. This study aimed to investigate general aspects of population structure and reproductive characteristics (size at first maturity, fecundity and reproductive output) of M. amazonicum from two important areas to artisanal prawn fishing located at the mouth of the Amazon River, State of Amapá. The specimens were captured using 20 handcrafted traps called "matapi". A number of 5,179 prawns were captured, 2,975 females and 2,195 males resulting in 1.35:1 female to male ratio. Santana Island and Mazagão Velho showed females predominated in the population. A reproductive peak period was observed from January to April/2009 and in December/2010, coinciding with the period of higher rainfall. The recruitment peak occurred in June and July/2009. Egg-bearing females ranged in size (carapace length) from 11.10 to 29.6 mm. Fecundity increased with female size and reached up to 7,417 eggs. This amount of eggs is considered low if compared with other Macrobrachium estuarine species. Mean egg volume increased gradually from 0.121 to 0.24 mm³ during embryogenesis, representing 68.5% of overall increase from Stage I to Stage III. Eggs of M. amazonicum are small; this is typical for Macrobrachium species, which depends on brackish water to complete the larval development. Irrespective of female size, reproductive output of M. amazonicum varied between 4.8 and 21.85% of their body weight into eggs production.(AU)

Macrobrachium amazonicum é uma espécie nativa vastamente distribuída nas bacias da America do Sul, sendo largamente explorada por pescadores artesanais no Norte e Nordeste do Brasil e com grande potencial para aquicultura. O objetivo deste trabalho foi abordar aspectos gerais da estrutura populacional e biologia reprodutiva (tamanho de primeira maturação, fecundidade e investimento reprodutivo) de M. amazonicum de duas importantes áreas de pesca artesanal de camarão localizada na foz do rio Amazonas, no Estado do Amapá. Os exemplares foram capturados usando 20 armadilhas artesanais, conhecidas localmente como matapi. Um total de 5.179 camarões foi capturado, dos quais 2.975 eram fêmeas e 2.195 eram machos, dando uma razão sexual geral de 1,35: 1 em favor das fêmeas. As proporções sexuais nas áreas de Ilha de Santana e Mazagão mostraram fêmeas predominando na população. Os picos reprodutivos nas duas áreas ocorreram de Janeiro a Abril/2009 e em Dezembro/2010, coincidindo com o período mais chuvoso. Os picos de recrutamento foram observados em junho e julho de 2009. O tamanho das fêmeas ovígeras variou de 11,10 mm a 29,6 mm de comprimento de carapaça. A fecundidade aumentou com o tamanho das fêmeas, chegando até 7.417 ovos, podendo ser considerada baixa comparada a outras espécies estuarinas de Macrobrachium. Volume médio dos ovos aumentou gradualmente durante a embriogênese saindo de 0,112 para 0,220 mm³, representando um aumento global de 68,5% do I ao III estágio embrionário. Os ovos de M. amazonicum podem ser considerados pequenos, típicos de espécies de Macrobrachium que dependem de água salgada para completar seu desenvolvimento larval. Independente do tamanho da fêmea, o investimento reprodutivo de M. amazonicum variou entre 4,8 e 21,85% do seu peso corporal para a produção de ovos.(AU)