DNA methylation level of gene SIRT1 in ram spermatozoa and relationship with fertilizing ability according to breed and age

Background: Effect of the epigenetic factors on the male fertility is well proofed. Sperm acts as a carrier of genetic material, and its DNA methylome can affect maternal pregnancy rate and offspring phenotype. However, the research on the DNA methylation in the spermatozoids of livestock males, in particular rams, is still limited. To best of our knowledge the data about as a global as well as gene specific DNA methylation in ram spermatozoa from different breeds and ages are missed in the scientific literature. The present study was designed to analyze the relationship between methylation levels of the important for spermatogenesis gene SIRT1 in spermatozoa and fertilizing ability of sperm in rams from different breeds and ages. Materials, Methods & Results: The ejaculates of 16 rams from Lacaune, East Friesian and Assaf breeds at age between 18 to 96 months were evaluated. The kinematic parameters of 2 semen samples from each animal were estimated by CASA. The separated spermatozoa were used for DNA extraction followed by bisulfite conversion. The DNA methylation of SIRT1 was detected through quantitative methylation-specific PCR using 2 sets of primers designed specifically for bisulfite-converted DNA sequences to attach methylated and unmethylated sites. The breed and age effect on the gene SIRT1 methylation by ANOVA was estimated. Experimental females included 393 clinically healthy milk ewes (Lacaune, n = 131; East Friesian sheep, n = 100 and Assaf, n = 162) in breeding season. Reproductive performances (conception rate at lambing, lambing percentage and fecundity) of ewes, inseminated by sperm of the investigated rams, were statistically processed. ANOVA showed that the animal breed influences significantly on the level of DNA methylation of gene SIRT1 in ram spermatozoa (P = 0.002) An average value of DNA methylation of SIRT1 in ram sperm from Lacaune breed was significantly higher than in Assaf and East Friesian (81.21 ± 15.1% vs 36.7 ± 14.2% and 38.3 ± 18.6 respectively, P < 0.01). The highest percent of SIRT1 methylation was observed in old animals compared to the young and middle-age. Moderate and strong correlations (r from 0.44 to 0.71, P < 0.05) between the methylation level of the SIRT1 gene in rams' sperm and reproductive parameters of inseminated ewes in all breeds were established. Discussion: Our data are the first message about the effect of breed on the specificity of DNA methylation of gene SIRT1 in ram spermatozoa. These results demonstrated an existence of the sheep breeds with high and low level of DNA methylation of gene SIRT1 in ram sperm. Although the effect of age on the methylation level in sperm is still discussable, our results showed a moderate correlation between age and methylation level of SIRT1 in spermatozoa of rams. Taking into account that DNA methylation in sperm is stabilized with puberty onset and is a heritable epigenetic modification, it can be a promising marker of sperm quality in animal breeding. In all investigated breeds the rams with relatively high level of DNA methylation of gene SIRT1 in spermatozoa (50-68%) demonstrated a high conception rate at lambing (> 70%). In conclusion, the DNA methylation level of the SIRT1 gene in ram spermatozoa is determined by both the breed and the age of the animals and correlates with fertilizing ability of sperm.

Effect of pre-pubertal growth rate of Sohagi ram lambs on some physiological parameters and sexual behavioral patterns at puberty

Abstract Thirty healthy Sohagi ram lambs with an average age of 188.6±7.3 days were used to study the effect of pre-pubertal growth rate on some physiological parameters and sexual behavioral patterns at puberty. Ram lambs were divided into three groups (10 animals per each group) according to the previous growth rate until 6 months of age. Groups were marked as fast, medium and slow growing. Animal groups were housed in closed barns with access to an open area. Results showed that age and weight of ram lambs at puberty were significantly affected (P<0.05) by the pre-pubertal growth rate. Ram lambs in the fast growing group were reached to onset puberty firstly at 272.6 days with body weight (BW) 37.1 kg on average then ram lambs in medium group (284.8 days with BW 32.7 kg), while ram lambs in slow growing group were the last (314.1 days with BW 32.5 kg). Blood‎ testosterone‎ concentration at puberty was not significantly different among growing groups (1.494± 0.03 ng/ml on average, ranged from 1.287 to 1.902 ng/ml). Testes measurements from 6 months of age until puberty show that ram lambs in fast growing group had the highest values of testes length, circumference and volume followed by those in medium and slow growing group. Sexual behavioral observation showed that flehmen and mounting behavior were significantly higher for ram lambs in fast growing group (5.63 and 6.75 number/12h) than slow growing group (4.25 and 5.38 number/12h) while in medium growing group were intermediate (4.88 and 5.88 number/12h). From these findings, could be concluded that age, weight and sexual behavioral patterns of Sohagi ram lambs at puberty were affected by pre-pubertal growth rate, and the breeders should strive to achieve good growth rates for their lambs before puberty which led to improving reproductive performance.

Effect of pre-pubertal growth rate of Sohagi ram lambs on some physiological parameters and sexual behavioral patterns at puberty

Thirty healthy Sohagi ram lambs with an average age of 188.6±7.3 days were used to study the effect of pre-pubertal growth rate on some physiological parameters and sexual behavioral patterns at puberty. Ram lambs were divided into three groups (10 animals per each group) according to the previous growth rate until 6 months of age. Groups were marked as fast, medium and slow growing. Animal groups were housed in closed barns with access to an open area. Results showed that age and weight of ram lambs at puberty were significantly affected (P<0.05) by the pre-pubertal growth rate. Ram lambs in the fast growing group were reached to onset puberty firstly at 272.6 days with body weight (BW) 37.1 kg on average then ram lambs in medium group (284.8 days with BW 32.7 kg), while ram lambs in slow growing group were the last (314.1 days with BW 32.5 kg). Blood‎ testosterone‎ concentration at puberty was not significantly different among growing groups (1.494± 0.03 ng/ml on average, ranged from 1.287 to 1.902 ng/ml). Testes measurements from 6 months of age until puberty show that ram lambs in fast growing group had the highest values of testes length, circumference and volume followed by those in medium and slow growing group. Sexual behavioral observation showed that flehmen and mounting behavior were significantly higher for ram lambs in fast growing group (5.63 and 6.75 number/12h) than slow growing group (4.25 and 5.38 number/12h) while in medium growing group were intermediate (4.88 and 5.88 number/12h). From these findings, could be concluded that age, weight and sexual behavioral patterns of Sohagi ram lambs at puberty were affected by pre-pubertal growth rate, and the breeders should strive to achieve good growth rates for their lambs before puberty which led to improving reproductive performance.(AU)

Influence of male on estrus behavior, estradiol and progesterone release and puberty onset on prepubertal Saanen goats / Influência do reprodutor sobre o comportamento de estro, liberação de estrógeno, progesterona e início da puberdade em cabras Saanen pré-puberes

The present study investigated the male effect on the estrus behaviors, estradiol and progesterone release in prepubertal Saanen goats. Twenty-nine female Saanen goats at 135 ± 10 days old with body weight of 22.8 ± 3.3 Kg were randomly assigned to three treatments: exposure to sexually active male (male treatment), exposure to androgenized females (androgenized female treatment), and prepubertal goats isolated from active male and androgenized females (control treatment). Sexual behaviors associated with estrus were recorded daily, and blood samples were taken weekly to determine estradiol and progesterone concentrations over 24 weeks. The experimental goats subjected to male or androgenized female had significantly higher frequency of estrus (mount acceptance) (P ≤ 0,02), progesterone (P ≤ 0,01), and estradiol (P ≤ 0,01) release than the control goats. Furthermore, goats exposed to a male showed estrus behavior two weeks earlier and maintained this estrus behavior for three weeks more than goats of both female and control treatments. Estrus was observed in 70 % of goats in male and female treatments during the breeding season versus 44 % of the control goats. Finally, significantly more goats subjected to male treatment (60 % of goats) showed progesterone concentrations higher than 1 ng mL-1 (which indicates the presence of a functional corpus luteum) compared to the female and control treatment (40 and 22 % of goats, respectively). These results shows that male treatment significantly increased the number of females showing estrus behavior, estradiol and progesterone release, and the number of animals with a functional corpus luteum, anticipating puberty for experimental goats, suggesting that the male effect could be used to anticipate the onset of puberty in goats.(AU)

O presente estudo investigou o efeito do macho sobre o comportamento do estro, liberação de estradiol e progesterona em cabritas Sannen pré-púberes. Vinte e nove cabritas com 135 ± 10 dias de idade e peso corporal de 22,8 ± 3,3 kg foram submetidas à três tratamentos: macho; fêmeas androgenizadas; controle (mantidas isoladas do efeito macho ou de fêmeas androgenizadas) . Os comportamentos sexuais foram registrados diariamente e as amostras de sangue foram colhidas semanalmente ao longo de 24 semanas. Os tratamentos macho e fêmea androgenizada aumentaram significativamente a ocorrência comportamental do estro (P ≤ 0,02), a concentração de progesterona (P ≤ 0,01) e estradiol (P ≤ 0,01) em comparação ao tratamento controle. As cabritas expostas ao efeito macho anteciparam o comportamento de estro em duas semanas, e o mantiveram por mais três semanas quando comparado às cabritas dos tratamentos fêmea androgenizada e controle. Apenas 44% das cabritas controle foram observadas em estro, sendo que 70% das cabritas submetidas aos tratamentos macho e fêmea androgenizada foram observadas em estro. Além disso, 60% das cabritas expostas ao efeito macho, 40 % das cabritas expostas ao efeito fêmea androgenizada e 22% das cabritas controle apresentaram concentrações de progesterona superiores a 1 ng mL-1, o que indica a presença de corpo lúteo funcional. De fato, o efeito macho aumentou significativamente o número de fêmeas em estro, a concentração de estradiol e progesterona, o número de fêmeas com corpo lúteo funcional, sugerindo que o efeito macho pode ser usado para antecipar o início da puberdade em cabritas Saanen.(AU)

Applications of Doppler ultrasonography in reproductive health and physiology of small ruminants / Aplicações da ultrassonografia Doppler na fisiologia e saúde reprodutiva de pequenos ruminantes

Major applications of Doppler ultrasonography for evaluating reproductive potential of healthy sheep and goats are discussed in this mini-review. Basic principles of Doppler imaging and examination techniques used are also briefly described. In ewes and does, Doppler ultrasonography has primarily been used in reproductive research involving superovulatory treatments and fetal development. In both species, color Doppler sonography has proven to be an accurate non-invasive method of detecting luteal structures and monitoring changes in luteal status/dynamics during the interovulatory period and pregnancy. Studies in rams have documented changes in testicular blood supply during the period encompassing the onset of puberty as well as seasonal fluctuations in velocimetric indices of testicular arteries and their relationships to spermatogenesis/semen quality, testicular volumes and circulating concentrations of reproductive hormones. Quantitative correlations between high-velocity antral follicular blood flow and superovulatory yields in ewes promise to provide a reliable non-invasive method to predict superovulatory outcomes. Umbilical cord hemodynamics are a useful marker of fetal development and health status. However, the relationships among velocimetric indices of major supplying arteries and ovarian/testicular or mammary gland function are still equivocal and require additional confirmatory studies of multiple influencing factors.(AU)

Applications of Doppler ultrasonography in reproductive health and physiology of small ruminants / Aplicações da ultrassonografia Doppler na fisiologia e saúde reprodutiva de pequenos ruminantes

Major applications of Doppler ultrasonography for evaluating reproductive potential of healthy sheep and goats are discussed in this mini-review. Basic principles of Doppler imaging and examination techniques used are also briefly described. In ewes and does, Doppler ultrasonography has primarily been used in reproductive research involving superovulatory treatments and fetal development. In both species, color Doppler sonography has proven to be an accurate non-invasive method of detecting luteal structures and monitoring changes in luteal status/dynamics during the interovulatory period and pregnancy. Studies in rams have documented changes in testicular blood supply during the period encompassing the onset of puberty as well as seasonal fluctuations in velocimetric indices of testicular arteries and their relationships to spermatogenesis/semen quality, testicular volumes and circulating concentrations of reproductive hormones. Quantitative correlations between high-velocity antral follicular blood flow and superovulatory yields in ewes promise to provide a reliable non-invasive method to predict superovulatory outcomes. Umbilical cord hemodynamics are a useful marker of fetal development and health status. However, the relationships among velocimetric indices of major supplying arteries and ovarian/testicular or mammary gland function are still equivocal and require additional confirmatory studies of multiple influencing factors.

New insights on the neuroendocrine control of puberty and seasonal breeding in female sheep

Timing of puberty has a great influence on animal productivity. For example, reproduction in sheep can be affected by seasonality, leading to fluctuations in availability of animal products. Therefore, optimization of birth dates would improve reproductive success in sheep. Since the discovery of the major role of kisspeptin and Kiss1R, its cognate receptor, in reproductive function, there are new opportunities for interventions. Repeated or continuous administration of native kisspeptin are able to hasten puberty and induce ovulation during breeding and non-breeding seasons of sheep. However, due to the short half-life of kisspeptin, protocols involving native kisspeptin are usually proof of concept, but not practical under field conditions. Consequently, there are efforts to develop kisspeptin analogues capable of replicating effects of repeated/continuous administration of native kisspeptin. In this review, we intended to provide a comprehensive summary of the neuroendocrine requirements for puberty onset and ovulation in adult ewes, focusing on kisspeptin, its physiological effects and responses to its analogues on reproductive function in ewes.

New insights on the neuroendocrine control of puberty and seasonal breeding in female sheep

Timing of puberty has a great influence on animal productivity. For example, reproduction in sheep can be affected by seasonality, leading to fluctuations in availability of animal products. Therefore, optimization of birth dates would improve reproductive success in sheep. Since the discovery of the major role of kisspeptin and Kiss1R, its cognate receptor, in reproductive function, there are new opportunities for interventions. Repeated or continuous administration of native kisspeptin are able to hasten puberty and induce ovulation during breeding and non-breeding seasons of sheep. However, due to the short half-life of kisspeptin, protocols involving native kisspeptin are usually proof of concept, but not practical under field conditions. Consequently, there are efforts to develop kisspeptin analogues capable of replicating effects of repeated/continuous administration of native kisspeptin. In this review, we intended to provide a comprehensive summary of the neuroendocrine requirements for puberty onset and ovulation in adult ewes, focusing on kisspeptin, its physiological effects and responses to its analogues on reproductive function in ewes.(AU)

Mammary artery Doppler ultrasonography of Brazilian Bergamasca dairy ewe lambs under the influence of two different feeding plans

ABSTRACT: Blood supply of mammary gland is extremely important, since it is a crucial factor in the mammary tissue development. The objective of this study was to describe and assess main mammary artery hemodynamic characteristics of lambs with two growth rates, using Doppler ultrasound. Two experimental groups, A and B, (n=10) of female Brazilian Bergamasca lambs were kept under the same management conditions and facilities. There were two phases: Phase 1, from 90 days of age until onset of puberty; Phase 2, from puberty until 1 year of age. During phase 1, a specific diet was formulated to each experimental group to obtain two different average daily gains: 150g, for treatment A, and 250g, for treatment B. During phase 2, there was no difference on the diet offered to both groups. Every 14 days, all animals were weighed and their body condition score was evaluated. Every 60 days, ultrasound exams (Doppler) of mammary artery were performed to obtain resistance and pulsatility indexes. Treatment B lambs showed higher weight gain and higher body condition score (P 0.05). However, for resistance and pulsatility indexes, there was no difference between treatments (P>0.05). Hemodynamic values remained constant, independent of diet or body development presented by the animals. Obtained data is valuable information on Bergamasca ewe lambs development.

RESUMO: O suprimento sanguíneo da glândula mamária é extremamente importante, uma vez que é um fator crucial para o desenvolvimento do tecido mamário. Assim, a necessidade de registro dos parâmetros de fluxo sanguíneo arterial é evidente. O objetivo do estudo foi descrever e avaliar as principais características hemodinâmicas da artéria mamária de cordeiras submetidas a diferentes taxas de crescimento, usando o ultrassom Doppler. Dois grupos experimentais, A e B, (n=10) de cordeiras da raça Bergamácia brasileira foram mantidas sob as mesmas condições de manejo e instalações. O estudo foi dividido em diferentes fases, sendo: Fase 1, de 90 dias de idade até o início da puberdade; Fase 2, desde a puberdade até 1 ano de idade. Durante a fase 1, dietas específicas foram formuladas para cada grupo experimental, a fim de obter duas médias diferentes de ganho de peso diário: 150g, para o tratamento A, e 250g, para o tratamento B. Durante a Fase 2, não houve diferença na dieta oferecida para os dois grupos. A cada 14 dias, todos os animais foram pesados e determinado o escore de condição corporal. A cada 60 dias, exames de ultrassom (Doppler) da artéria mamária foram realizados a fim de calcular os índices de resistência e pulsatilidade. As cordeiras do tratamento B registrou maior ganho de peso e escore de condição corporal (P 0,05). No entanto, não houve diferença para os índices de resistência e pulsatilidade entre os tratamentos (P>0,05). Os valores hemodinâmicos permaneceram constantes, independente da dieta ou o desenvolvimento do corpo apresentada pelos animais. Assim, os dados obtidos são informações valiosas sobre o desenvolvimento da raça a que se refere.

Onset of reproductive activity of white and natural colored corriedale ewe labms

The objective of this study was to estimate differences in growth, plasma progesterone (P4) and age at puberty between white and natural colored Corriedale ewe lambs. Thirty ewe lambs with average age of 12 months were randomly allocated to genetic groups: white (WC, n = 15) and natural colored (NC, n = 15). Ewes were maintained under extensive grazing conditions on natural pasture, and herbage mass was estimated over a 28-day experimental period. Morphometric measurements (front and hind height, body length, thoracic perimeter, rump length and width, wool fiber length), body condition score (CC) and weight were taken at 28-day intervals. There was no effect of genetic group on body weight, average daily gain and morphometric measurements (P > 0.05). The WC ewe lambs had longer fiber length (P 0.05); however, it increased above 1ng ml-1 in NC from January onward and in WC from March onwards. Estrus was detected at the same time in both groups. The results of this study indicate that both genetic groups have similar growth patterns and ovarian activities.

Onset of reproductive activity of white and natural colored corriedale ewe labms

The objective of this study was to estimate differences in growth, plasma progesterone (P4) and age at puberty between white and natural colored Corriedale ewe lambs. Thirty ewe lambs with average age of 12 months were randomly allocated to genetic groups: white (WC, n = 15) and natural colored (NC, n = 15). Ewes were maintained under extensive grazing conditions on natural pasture, and herbage mass was estimated over a 28-day experimental period. Morphometric measurements (front and hind height, body length, thoracic perimeter, rump length and width, wool fiber length), body condition score (CC) and weight were taken at 28-day intervals. There was no effect of genetic group on body weight, average daily gain and morphometric measurements (P > 0.05). The WC ewe lambs had longer fiber length (P < 0.05). Plasma P4 was similar between genotypes (P > 0.05); however, it increased above 1ng ml-1 in NC from January onward and in WC from March onwards. Estrus was detected at the same time in both groups. The results of this study indicate that both genetic groups have similar growth patterns and ovarian activities.(AU)

Mammary artery Doppler ultrasonography of Brazilian Bergamasca dairy ewe lambs under the influence of two different feeding plans / Avaliação ultrassonográfica por Doppler da artéria mamária de cordeiras da raça Bergamácia Brasileira sob a influência de dois planos de alimentação diferentes

Blood supply of mammary gland is extremely important, since it is a crucial factor in the mammary tissue development. The objective of this study was to describe and assess main mammary artery hemodynamic characteristics of lambs with two growth rates, using Doppler ultrasound. Two experimental groups, A and B, (n=10) of female Brazilian Bergamasca lambs were kept under the same management conditions and facilities. There were two phases: Phase 1, from 90 days of age until onset of puberty; Phase 2, from puberty until 1 year of age. During phase 1, a specific diet was formulated to each experimental group to obtain two different average daily gains: 150g, for treatment A, and 250g, for treatment B. During phase 2, there was no difference on the diet offered to both groups. Every 14 days, all animals were weighed and their body condition score was evaluated. Every 60 days, ultrasound exams (Doppler) of mammary artery were performed to obtain resistance and pulsatility indexes. Treatment B lambs showed higher weight gain and higher body condition score (P<0.05). However, for resistance and pulsatility indexes, there was no difference between treatments (P>0.05). Hemodynamic values remained constant, independent of diet or body development presented by the animals. Obtained data is valuable information on Bergamasca ewe lambs development.(AU)

O suprimento sanguíneo da glândula mamária é extremamente importante, uma vez que é um fator crucial para o desenvolvimento do tecido mamário. Assim, a necessidade de registro dos parâmetros de fluxo sanguíneo arterial é evidente. O objetivo do estudo foi descrever e avaliar as principais características hemodinâmicas da artéria mamária de cordeiras submetidas a diferentes taxas de crescimento, usando o ultrassom Doppler. Dois grupos experimentais, A e B, (n=10) de cordeiras da raça Bergamácia brasileira foram mantidas sob as mesmas condições de manejo e instalações. O estudo foi dividido em diferentes fases, sendo: Fase 1, de 90 dias de idade até o início da puberdade; Fase 2, desde a puberdade até 1 ano de idade. Durante a fase 1, dietas específicas foram formuladas para cada grupo experimental, a fim de obter duas médias diferentes de ganho de peso diário: 150g, para o tratamento A, e 250g, para o tratamento B. Durante a Fase 2, não houve diferença na dieta oferecida para os dois grupos. A cada 14 dias, todos os animais foram pesados e determinado o escore de condição corporal. A cada 60 dias, exames de ultrassom (Doppler) da artéria mamária foram realizados a fim de calcular os índices de resistência e pulsatilidade. As cordeiras do tratamento B registrou maior ganho de peso e escore de condição corporal (P<0,05). No entanto, não houve diferença para os índices de resistência e pulsatilidade entre os tratamentos (P>0,05). Os valores hemodinâmicos permaneceram constantes, independente da dieta ou o desenvolvimento do corpo apresentada pelos animais. Assim, os dados obtidos são informações valiosas sobre o desenvolvimento da raça a que se refere.(AU)

Mammary artery Doppler ultrasonography of Brazilian Bergamasca dairy ewe lambs under the influence of two different feeding plans / Avaliação ultrassonográfica por Doppler da artéria mamária de cordeiras da raça Bergamácia Brasileira sob a influência de dois planos de alimentação diferentes

Blood supply of mammary gland is extremely important, since it is a crucial factor in the mammary tissue development. The objective of this study was to describe and assess main mammary artery hemodynamic characteristics of lambs with two growth rates, using Doppler ultrasound. Two experimental groups, A and B, (n=10) of female Brazilian Bergamasca lambs were kept under the same management conditions and facilities. There were two phases: Phase 1, from 90 days of age until onset of puberty; Phase 2, from puberty until 1 year of age. During phase 1, a specific diet was formulated to each experimental group to obtain two different average daily gains: 150g, for treatment A, and 250g, for treatment B. During phase 2, there was no difference on the diet offered to both groups. Every 14 days, all animals were weighed and their body condition score was evaluated. Every 60 days, ultrasound exams (Doppler) of mammary artery were performed to obtain resistance and pulsatility indexes. Treatment B lambs showed higher weight gain and higher body condition score (P<0.05). However, for resistance and pulsatility indexes, there was no difference between treatments (P>0.05). Hemodynamic values remained constant, independent of diet or body development presented by the animals. Obtained data is valuable information on Bergamasca ewe lambs development.(AU)

O suprimento sanguíneo da glândula mamária é extremamente importante, uma vez que é um fator crucial para o desenvolvimento do tecido mamário. Assim, a necessidade de registro dos parâmetros de fluxo sanguíneo arterial é evidente. O objetivo do estudo foi descrever e avaliar as principais características hemodinâmicas da artéria mamária de cordeiras submetidas a diferentes taxas de crescimento, usando o ultrassom Doppler. Dois grupos experimentais, A e B, (n=10) de cordeiras da raça Bergamácia brasileira foram mantidas sob as mesmas condições de manejo e instalações. O estudo foi dividido em diferentes fases, sendo: Fase 1, de 90 dias de idade até o início da puberdade; Fase 2, desde a puberdade até 1 ano de idade. Durante a fase 1, dietas específicas foram formuladas para cada grupo experimental, a fim de obter duas médias diferentes de ganho de peso diário: 150g, para o tratamento A, e 250g, para o tratamento B. Durante a Fase 2, não houve diferença na dieta oferecida para os dois grupos. A cada 14 dias, todos os animais foram pesados e determinado o escore de condição corporal. A cada 60 dias, exames de ultrassom (Doppler) da artéria mamária foram realizados a fim de calcular os índices de resistência e pulsatilidade. As cordeiras do tratamento B registrou maior ganho de peso e escore de condição corporal (P<0,05). No entanto, não houve diferença para os índices de resistência e pulsatilidade entre os tratamentos (P>0,05). Os valores hemodinâmicos permaneceram constantes, independente da dieta ou o desenvolvimento do corpo apresentada pelos animais. Assim, os dados obtidos são informações valiosas sobre o desenvolvimento da raça a que se refere.(AU)

The timing of puberty (oocyte quality and management)

This review aims at giving an overview on the physiological events leading to puberty onset in mammals and more specifically in cattle. Puberty is an important developmental milestone in mammals involving numerous changes in various physiological regulations and behaviors. It is a physiological unique event integrating several important central regulations at the crossroad of adaptation to environment: reproductive axis, feeding behavior and nutritional controls, growth, seasonal rhythm and stress. Puberty onset is also an important economic parameter in replacement heifer program and in genomic selection (genomic bulls). The quest for advanced puberty onset should be carefully balanced by its impact on physiological parameters of the animal and its offspring. Thus one has to carefully consider each step leading to puberty onset and set up a strategy that will lead to early puberty without being detrimental in the long term. In this review, major contributions in the understanding of puberty process obtained in rodents, primates and farm animals such as sheep and cattle are discussed. In the first part we will detail the endocrine events leading to puberty onset with a special focus on the regulation of GnRH secretion. In the second part we will describe the neural mechanisms involved in silencing and reactivating the GnRH neuronal network.

The timing of puberty (oocyte quality and management)

This review aims at giving an overview on the physiological events leading to puberty onset in mammals and more specifically in cattle. Puberty is an important developmental milestone in mammals involving numerous changes in various physiological regulations and behaviors. It is a physiological unique event integrating several important central regulations at the crossroad of adaptation to environment: reproductive axis, feeding behavior and nutritional controls, growth, seasonal rhythm and stress. Puberty onset is also an important economic parameter in replacement heifer program and in genomic selection (genomic bulls). The quest for advanced puberty onset should be carefully balanced by its impact on physiological parameters of the animal and its offspring. Thus one has to carefully consider each step leading to puberty onset and set up a strategy that will lead to early puberty without being detrimental in the long term. In this review, major contributions in the understanding of puberty process obtained in rodents, primates and farm animals such as sheep and cattle are discussed. In the first part we will detail the endocrine events leading to puberty onset with a special focus on the regulation of GnRH secretion. In the second part we will describe the neural mechanisms involved in silencing and reactivating the GnRH neuronal network.(AU)

Influence of feeding differentiation on the age at onset of puberty in Brazilian Bergamasca dairy ewe lambs / Influência da diferenciação alimentar na idade à puberdade em cordeiras da raça Bergamácia Brasileira

The objective of the study was to evaluate body growth and age at onset of puberty on lambs fed two specific diets for low and high growth rates. A herd of 20 Brazilian Bergamasca lambs was divided in two groups (n= 10) and kept confined throughout the experimental period, two animals of the same treatment/pen. Two phases were established: Phase 1, from 90 days of age until the onset of puberty; and Phase 2, from puberty onset up to 1 year old. For Phase 1, two distinct diets were formulated, being: Treatment A, which was formulated to obtain an average daily gain of approximately 150g; and Treatment B, for an average daily gain of about 250g. In Phase 2, a balanced, equal diet was provided to both groups. Every 14 days, the animals were weighed and given average daily gain, average daily dry matter intake and body condition score. From the 5th month of age on, in each group, a vasectomized male was used to detect estrus, establishing age at puberty onset and estrus interval for each lamb. Blood samples were collected every 28 days to determine plasma growth hormone concentration. Treatment B lambs gained more weight and had higher body condition score (P<0.05) and there was no difference for age at puberty onset and plasma growth hormone levels (P>0.05) between treatments. It was found that both treatments showed satisfactory performances. Thus, treatment A may be indicated as a reasonable feeding system to achieve positive responses on confined ewe lambs during growth phase.(AU)

O objetivo do estudo foi avaliar o crescimento corporal e idade de início da puberdade em cordeiras sob duas dietas específicas para taxas de crescimento baixas e altas. Um rebanho de 20 cordeiras Bergamácia Brasileira foi dividido em dois grupos (n= 10) e mantido confinado em todo período experimental, sendo dispostos dois animais do mesmo tratamento/baia. Duas fases foram estabelecidas: Fase 1, a partir de 90 dias de idade até o início da puberdade, e Fase 2, a partir do início da puberdade até 1 ano de idade. Para a fase 1, duas dietas distintas foram formuladas, sendo: Tratamento A, formulada para obter um ganho de peso diário de aproximadamente 150g; e Tratamento B, para um ganho de peso médio diário de cerca de 250g. Na Fase 2, uma dieta equilibrada idêntica foi fornecida para ambos os grupos. A cada 14 dias, os animais foram pesados e calcularam-se o ganho médio diário, o consumo médio diário de matéria seca e escore de condição corporal. A partir do quinto mês de idade, em cada grupo, um macho vasectomizado foi usado para detectar estro, estabelecendo a idade de início da puberdade e estro para cada cordeira. As amostras de sangue foram coletadas a cada 28 dias para determinar a concentração plasmática de hormônio do crescimento. Cordeiras do tratamento B ganharam mais peso e tiveram maior escore de condição corporal (P<0,05), mas não houve diferença de idade para o início da puberdade e para os níveis plasmáticos de hormônio do crescimento (P>0,05). Verificou-se que os tratamentos A e B apresentaram desempenhos satisfatórios. Assim, o tratamento A pode ser indicado como um sistema de alimentação para alcançar respostas positivas em cordeiras submetidas ao confinamento durante a fase de crescimento.(AU)

PERFIL SÉRICO DO HORMÔNIO ANTIMULLERIANO DURANTE A PERIPUBERDADE EM TOURINHOS NELORE

Objetivou-se avaliar a concentração do AMH em tourinhos Nelore na peripuberdade para verificar sua eficácia como preditor de precocidade sexual, correlacionando-a com as variáveis andrológicas. Foram selecionados 8 animais de 8 meses de idade, sendo avaliados nos estádios de desenvolvimento sexual por 150 dias, de -60 a +60, durante a peripuberdade, fazendo-se correlação entre idade e viabilidade seminal. Para as coletas de sêmen utilizou-se o método de eletroejaculação. Usou-se microscópio óptico com aumento de 10x para a análise das condições físicas e morfológicas do sêmen. Para mensuração do AMH, foi coletado sangue diretamente por punção jugular, utilizando-se o kit ELISA (AL-114/AnshLabs® ) para determinar a concentração. Os valores médios com desvio padrão para peso, CE e AMH dentro dos períodos de -60, -30, 0, +30 e +60 foram de (244,5±11,4, 16,75±1,25 e 611,35±200,02), (250,75±12,5, 17,625±1,375 e 554,94±393,16), (259,375±13,62, 18,625±1,37 e 621,61±285,15), (271,25±15,75, 19,75±1 e 370,36±134,44) e (283,5±18,00, 20,75±1,5 e 51,65±17,80), respectivamente. Observou-se que, as concentrações de AMH declina a partir da puberdade, havendo significância 60 dias após o início da puberdade, não havendo correlação com as variáveis andrológicas analisadas. Assim, conclui-se que a concentração de AMH não é uma boa ferramenta para predizer o momento da puberdade em tourinhos Nelore.

The aim of this study was to evaluate the concentration of AMH in Nellore bulls in peripuberty to verify its effectiveness as a predictor of sexual precocity, correlating it with andrological variables. Eight 8-month-old animals were selected and evaluated at the stages of sexual development for 150 days, from -60 to +60, during peripuberty, making a correlation between age and seminal viability. For semen collections, the electroejaculation method was used. An optical microscope with 10x magnification was used to analyze the physical and morphological conditions of the semen. To measure the AMH, blood was collected directly by jugular puncture, using the ELISA kit (AL-114/AnshLabs®) to determine the concentration. The mean values with standard deviation for weight, CE and AMH within the periods of -60, -30, 0, +30 and +60 were (244.5±11.4, 16.75±1.25 and 611, 35±200.02), (250.75±12.5, 17.625±1.375 and 554.94±393.16), (259.375±13.62, 18.625±1.37 and 621.61±285.15), (271.25±15.75, 19.75±1 and 370.36±134.44) and (283.5±18.00, 20.75±1.5 and 51.65±17.80), respectively. It was observed that AMH concentrations decline from puberty onwards, with significance 60 days after puberty onset, with no correlation with the andrological variables analyzed. Thus, it is concluded that the AMH concentration is not a good tool to predict the time of puberty in Nellore bulls.

Avaliação da ocorrência de puberdade em cobaias Short Hair mantidas em instalação animal

Animais de laboratório são cruciais no desenvolvimento científico e biomodelos, como as cobaias (Cavia porcellus), são importantes na cadeia de desenvolvimento, controle de qualidade de vacinas e medicamentos distribuídos no sistema único de saúde (SUS). Conhecer os parâmetros biológicos e fisiológicos é fundamental na criação e manutenção de animais em instalações animais, assim o manejo é adequado sempre que novas informações são conhecidas, visando o bem-estar e alinhamento aos 3Rs. Na busca por conhecimentos dos parâmetros reprodutivos em cobaias, o presente estudo teve como objetivo estudar o início da puberdade, a incidência e frequência do ciclo estral com idade entre 15 e 60 dias em cobaias short hair, além de comparar duas técnicas de coloração. As cobaias apresentam uma membrana de oclusão vaginal, que recobre o acesso ao orifício vaginal, a ruptura ocorre de maneira gradual e natural, momentos antes do parto e no período de cio. No presente estudo foram acompanhadas 42 fêmeas, quanto ao status da membrana de oclusão vaginal e, quando observada a ruptura espontânea, foi realizada coleta em swab para exame colpocitológico. Foi observado rompimento da membrana de oclusão vaginal em 39 das 42 fêmeas acompanhadas, seis fêmeas apresentaram abertura da membrana vaginal com menos de 21 dias de vida. Foram constatadas, ao longo de todo o estudo, 23 fêmeas com caracterização da fase de estro, exame de citologia esfoliativa vaginal, com esfregaço apresentando predomínio de células superficiais anucleadas, uma dessas fêmeas com idade inferior a 21 dias. O tempo de permanência de abertura da membrana de oclusão vaginal apresentou maior frequência entre 1 e 3 dias ininterruptos, a duração do intervalo da abertura da membrana vaginal ocorrendo com maior frequência entre 18 e 19 dias. Foi possível o acompanhamento de 3 períodos de ciclo estral em parte das fêmeas. As duas técnicas de coloração empregadas possibilitou caracterizar e contabilizar os tipos celulares do epitélio vaginal de cobaias. Os resultados do estudo contribuem com novas informações acerca de dados reprodutivos de cobaias, a idade de inicio da puberdade e apontou a necessidade de mudança nas práticas de manejo das cobaias e adequação da idade de desmame usualmente utilizados no ICTB / Fiocruz.

Laboratory animals are crucial in scientific development and biomodels, such as guinea pigs (Cavia porcellus), are important in the development chain and in quality control of vaccines and medicines distributed in the Unified Health System (SUS). Knowing the biological and physiological parameters is fundamental in the breeding and maintenance of animals in animal facilities, so the management is adequate whenever new information is known, aiming at the well-being and alignment with the 3R's. In the search for knowledge of reproductive parameters in guinea pigs, this study aimed to study the onset of puberty, the incidence and frequency of the estrous cycle aged between 15 and 60 days in guinea pigs Short Hair, in addition to comparing two cytological staining techniques. Guinea pigs have a vaginal occlusion membrane, which covers access to the vaginal orifice, the rupture occurs gradually and naturally, moments before the parturition and in the heat period. In the present study, 42 females were monitored regarding the status of the vaginal occlusion membrane and, when spontaneous rupture was observed, swab collection was performed for colpocytological examination. Disruption of the vaginal occlusion membrane was observed in 39 of the 42 females followed, six females had an opening of the vaginal membrane with less than 21 days of life. Throughout the study, 23 females were found with estrus phase characterization, vaginal exfoliative cytology exam, with smear presenting predominance of anucleated surface cells, one of these females under 21 days of age. The permanence time of opening the vaginal occlusion membrane was more frequent between 1 and 3 days uninterrupted, the duration of the interval of opening of the vaginal membrane occurring more frequently between 18 and 19 days. It was possible to follow 3 periods of estrous cycle in part of the females. The two staining techniques employed made it possible to characterize and account for the cell types of the guinea pig vaginal epithelium. The study results contribute with new informations about guinea pig reproductive data, the age of onset of puberty and pointed out the need to change guinea pig management practices and adjust the weaning age usually used in the ICTB / Fiocruz.

Restrição proteica durante os períodos intrauterino e lactacional: efeitos no desenvolvimento testicular de ratos pré-púberes / Protein restriction during intrauterine and lactation periods: effects on testicular development in pre-puberty rats

O objetivo deste estudo foi investigar o efeito da restrição proteica materna durante prenhez e lactação no testículo de ratos imaturos. Fêmeas de ratos Wistar foram acasaladas e, uma vez confirmada a gestação, foram divididas em dois grupos e alimentadas durante a prenhez e a lactação: grupo desnutrido (GD), dieta com caseína 8%, e grupo controle (GC), dieta com caseína 17%. Após o desmame, os machos de ambas as proles receberam a dieta normal até os 35 dias de idade, quando ocorreu a eutanásia. O peso corporal e o peso testicular diminuíram no GD com relação ao GC. A densidade volumétrica dos túbulos seminíferos foi maior no GC, assim como o espaço intertubular aumentou no GD. O número de túbulos seminíferos luminados foi maior no GC comparado ao GD. Diâmetro tubular, altura do epitélio seminífero e comprimento total dos túbulos seminíferos diminuíram no GD. Espermátides arredondadas foram frequentemente encontradas nas seções transversais do GC. Por outro lado, espermatócitos I em prófase foram o tipo celular mais frequentemente encontrado no GD. A desnutrição durante a gestação e a lactação em ratos Wistar machos alteraram parâmetros morfométricos testiculares relacionados ao compartimento tubular e atrasou o início da espermatogênese.(AU)

Current study investigates the effects of maternal protein restriction during pregnancy and lactation on the testis of immature rats. Female Wistar rats were mated and, after confirming pregnancy, they were divided into two groups: undernourished group (UG) fed on a diet with casein 8%, and control group (CG) fed on a diet with casein 17 %, during pregnancy and lactation. After weaning, male offspring from the two experimental groups were fed on normal diet up to 35 days old when they were euthanized. Body and testicular weights decreased in UG when compared to those in CG. Volumetric density of seminiferous tubules was higher in CG whilst intertubular space increased in UG. The number of lumenated seminiferous tubules was higher in CG than in UG. Tubular diameter, seminiferous epithelium height and total length of seminiferous tubules were lower in UG. Round spermatids were frequently found in seminiferous tubules cross-section of CG. On the other hand, spermatocytes I in prophases was the germ cell commonly found in seminiferous tubules cross-sections of UG. Undernutrition during pregnancy and lactation period of the male Wistar rats altered the morphometric testicular parameters related to tubular compartment and delayed the onset of spermatogenesis.(AU)

XXX - RELAÇÃO ENTRE MEDIDAS DE EFICIÊNCIA ALIMENTAR COM O DESEMPENHO REPRODUTIVO E DEPOSIÇÃO DE GORDURA EM NOVILHAS BRANGUS

O estudo foi realizado com o objetivo de analisar o efeito do grau de eficiência para consumo alimentar residual (CAR) sobre o desempenho reprodutivo de novilhas Brangus, em seu primeiro serviço aos 13/15 meses de idade. As avaliações foram efetuadas em duas ocasiões: pós-desmame, quando da realização do teste de eficiência alimentar e durante a estação reprodutiva. Primeiramente, foi verificado o impacto da inclusão da espessura de gordura subcutânea no modelo de predição para CAR sobre: características de desempenho, outras medidas de eficiência alimentar, como o consumo e o ganho de peso residual (CGPR), e reprodutiva. Não foram encontradas diferenças nas variáveis estudadas, incluindo taxa de concepção, entre as classes de CAR, em nenhum dos modelos utilizados. Evidenciou-se uma redução no consumo de alimento pelos animais mais eficientes. A realização da classificação das novilhas quando a CGPR, utilizando em seu cálculo o CAR ajustado, pode ser uma medida alternativa de eficiência alimentar, pois visa selecionar animais com menores consumos e maiores ganhos de peso, sem impactar na deposição de gordura dos animais. Posteriormente, verificaram-se as relações do CAR com a precocidade sexual das novilhas e seu desempenho reprodutivo em sua primeira estação de acasalamento. Foi observado que novilhas classificadas como peripuberais, 30 dias antes da estação reprodutiva, apresentaram maior frame, valor de escore de trato reprodutivo (ETR) e taxa de crescimento em comparação às impúberes. Não houve diferença de taxa de concepção entre as classes de CAR. A taxa de concepção ao final da estação reprodutiva foi de 76,27%. A espessura de gordura na picanha, entre as variáveis estudadas, foi a que mais influenciou as taxas de concepção (7 a 10%), neste grupo de animais, por atuar como um sinalizador do status nutricional para o eixo neuroendócrino e, com isso, impactar sobre o início da puberdade das novilhas. Os resultados deste estudo indicam que o ajuste do modelo para estimativas de CAR, incluindo a espessura de gordura subcutânea final, pode ser uma estratégia para amenizar os possíveis efeitos negativos da seleção para esta característica sobre a composição corporal e não afeta o desempenho reprodutivo das fêmeas.

The objective of this study was to analyze the effect of the efficiency level for residual food intake (RFI) on the reproductive performance of Brangus heifers, in their first service at 13/15 months of age. The evaluations were carried out on two occasions: post-weaning, during the performance of the food efficiency test and during the breeding season. First, the impact of the inclusion of subcutaneous fat thickness in the prediction model for RFI was verified on: performance characteristics, other food efficiency measures, such as residual intake and body weight gain (RIG), and reproductive performance. No differences were found in the studied variables, including conception rate, among RFI classes, in none of the models used. A reduction in food consumption by the most efficient animals was evidenced. The classification of heifers when RIG, using the adjusted RFI, may be an alternative measure of food efficiency, since it aims to select animals with lower intakes and higher weight gains, without impacting the fat deposition of the animals. Subsequently, the relationships of the RFI with the sexual precocity of the heifers and their reproductive performance in their first mating season were verified. It was observed that heifers classified as peripubertal, 30 days before the reproductive season, had a higher frame, reproductive tract score (RTS) and growth rate compared to the unpublished. There was no difference in conception rate among RFI classes. The design rate at the end of the reproductive season was 76.27%. The rump fat thickness among the studied variables was the one that most influenced the design rates (7 to 10%) in this group of animals, since it acts as a sign of the nutritional status for the neuroendocrine axis and, with this, impact on the onset of puberty of heifers. The results of this study indicate that the adjustment of the model to RFI estimates, including final subcutaneous fat thickness, may be a strategy to mitigate the possible negative effects of selection for this trait on body composition and does not affect the reproductive performance of females.