Jurandir Ferreira da Cruz

Role of melatonin on production and preservation of gametes and embryos: a brief review.

The aim of this brief review is to clarify the role of melatonin in the production and preservation of mammalian gametes and embryos. Melatonin is an indoleamine synthesized from tryptophan in the pineal gland and other organs that operates as a hypothalamic-pituitary-gonadal axis modulator and regulates the waxing and waning of seasonal reproductive competence in photoperiodic mammals. A major function of the melatonin rhythm is to transmit information about the length of the daily photoperiod to the circadian and circannual systems in order to provide time-of-day and time-of-year information, respectively, to the organism. Melatonin is also a powerful antioxidant and anti-apoptotic agent, which is due to its direct scavenging of toxic oxygen derivatives and its ability to reduce the formation of reactive species. Mammalian gametes and embryos are highly vulnerable to oxidative stress due to the presence of high lipid levels; during artificial breeding procedures, these structures are exposed to dramatic changes in the microenvironment, which have a direct bearing on their function and viability. Free radicals influence the balance between oxidation-reduction reactions, disturb the transbilayer-phospholipid asymmetry of the plasma membrane and enhance lipid peroxidation. Melatonin, due to its amphiphilic nature, is undoubtedly useful in tissues by protecting them from free radical-mediated oxidative damage and cellular death. The supplementation of melatonin to semen extender or culture medium significantly improves sperm viability, oocyte competence and blastocyst development in vitro.

Essential actions of melatonin in protecting the ovary from oxidative damage

Free radicals and other reactive species are involved in normal ovarian physiology. However, they are also highly reactive with complex cellular molecules (proteins, lipids, and DNA) and alter their functions leading to oxidative stress. Oxidative damage may play a prominent role in the development of disorders that considerably influence female fertility. Melatonin, because of its amphiphilic nature that allows for crossing morphophysiological barriers, is an effective antioxidant for protecting macromolecules against oxidative stress caused by reactive species. The balance between reactive oxygen species and antioxidants within the follicle seems to be critical to the function of the oocyte and granulosa cells and evidence has accumulated showing that melatonin is involved in the protection of these cells. Melatonin appears to have varied functions at different stages of follicle development, oocyte maturation, and luteal stage. Melatonin concentration in the growing follicle may be an important factor in avoiding atresia, because melatonin in the follicular fluid reduces apoptosis of critical cells. Melatonin also has protective actions during oocyte maturation reducing intrafollicular oxidative damage. An association between melatonin concentrations in follicular fluid and oocyte quality has been reported; this would allow a preovulatory follicle to fully develop and provide a competent oocyte for fertilization. The functional role of reactive species and the cytoprotective properties of melatonin on the ovary from oxidative damage are summarized in this brief review.

Effect of follicular fluid supplementation during in vitro maturation on total cell number in bovine blastocysts produced in vitro

This study evaluated the influence of follicular fluid (FF) added to the maturation medium on the quality of bovine embryos produced in vitro. In the first experiment, oocytes were matured in media containing five different FF concentrations with different maturation times and classified according to meiotic progression and migration of cortical granules. In the second experiment, oocytes matured in the same media were fertilized at three different maturation times; thereafter, cleavage and blastocyst rates were evaluated. In the third experiment, oocytes were matured in media containing three different FF concentrations at two different maturation times, and embryo quality, inferred by the ratio of inner cell mass and trophectoderm cells compared with total cell number, was evaluated. Higher FF concentration (75 - 100% FF) slowed meiotic progression and CG migration (control - 78.13% vs. treated - 52.58% and control - 52.7% vs. treated - 11.59%, respectively, at 24 h of maturation). Also, FF at concentration of 75% or 100% had a negative influence on cleavage and blastocyst rates (control - 90.13% vs. treated - 82.64% and control - 35.73% vs. treated - 11.57%, respectively, at 24 h of maturation). The 50% FF resulted in embryos with increased inner cell mass numbers (control - 29.91 vs. treated - 35.49, at 24 h of maturation) and total cell numbers (control - 109.53 vs. treated - 120.67, at 26 h of maturation). Even though higher concentration of FF added to the maturation medium reduced embryonic development rates, in lower concentrations, FF slowed the meiotic progression and migration of CG and contributed to increases in inner cell mass number. Thus, FF added to the maturation medium enhances the number of cells in bovine embryos produced in vitro, especially for inner cell mass.

Diversidade fenotípica de linhagens de ovinos Santa Inês por meio de análise multivariada

Objetivou-se com este estudo avaliar a diversidade fenotipica de linhagens de ovinos Santa Ines. Doze medidas corporais foram realizadas em 502 femeas adultas descendentes de 34 reprodutores pertencentes a 15 linhagens da raca Santa Ines, registrados junto a associacao de criadores: Altura Anterior, Altura Posterior, Altura das Pernas, Altura do Torax, Circunferencia Toracica, Circunferencia da Canela, Comprimento do Corpo, Comprimento do Pescoco, Comprimento de Orelha, Comprimento da Face, Comprimento do Chanfro e Largura da Face. Os dados foram submetidos a analise de Variaveis Canonicas e a analise de agrupamento pelo metodo da ligacao media entre grupos. As tres primeiras Variaveis Canonicas explicaram 81,01% da variacao total. As linhagens 1, 10 e 11 foram as mais homogeneas, enquanto que as linhagens 3, 6, 9, 12 e 15 apresentaram grande variabilidade intra-populacional. As linhagens 11 e 15 foram as que apresentaram maior distância (Mahalanobis). A analise de agrupamento mostrou a formacao de tres grupos. As cinco medidas corporais com maior importância relativa (Circunferencia Toracica, Circunferencia da Canela, Comprimento da Face, Comprimento de Pescoco e Comprimento de Chanfro), consideradas conjuntamente, explicaram 76,89% da diversidade fenotipica entre as linhagens. As linhagens de ovinos Santa Ines apresentam alta diversidade fenotipica, sendo que as caracteristicas relacionadas a producao e a caracterizacao racial apresentam importância semelhante na diferenciacao entre linhagens.

Prevalência e histopatologia de lesões sugestivas de tuberculose em carcaça de bovinos abatidos no Sudoeste da Bahia

The aim of this study was to determine the prevalence of suggestive tuberculosis lesions in cattle carcass slaughtered in Southwestern Bahia. From March to November 2012, 58,268 slaughtered animals were inspected in a slaughterhouse in Vitoria da Conquista-BA. The inspection consisted in a systematic evaluation of the lymph nodes and organs searching for suggestive lesions, through visual and tactile examination with subsequent incision of the lymph nodes. The prevalence of animals showing suggestive lesions of tuberculosis in the anatomopathological inspection was 0.12%. The most affected lymph nodes were prescapular (51.5%) tracheobronchial (19.2%) and ischiatic (11.1%). From lymph nodes, which showed presumptive lesions, 60.6% had histological changes suggestive of mycobacteria and 10.0% showed acid-fast bacilli by Ziehl-Neelsen staining, therefore, positive to mycobacteria. In conclusion, the prevalence of cattle carcasses with suggestive lesions of tuberculosis in Southwestern Bahia is low, but at the same time, brings up the necessity of intensification of actions for the control and eradication of this zoonosis in the Bahia State.

Parâmetros populacionais da raça ovina Santa Inês no Brasil

The objective of this work was to evaluate the population structure of the sheep breed Santa Ines raised in Brazil. Pedigree data from 13,216 animals, belonging to 53 herds from eight Brazilian states, born between 1976 and 2010, were used. The program Endog was used for pedigree analysis and estimation of population parameters. From the total number of animals studied, 80.86% had a pedigree in the first ascendancy, 73.78% in the second, and 67.75% in the third. The maximum number of known generations was 19, and the average of equivalent generations was 4.67. The average generation interval was 3.22±1.77 years. The mean effective population size was of 172.5 animals. The number of founder animals was 829, but the effective number of founders was only 50. The 17 main ancestors accounted for 50% of the total genetic variability. The average relatedness coefficient was of 3.87% and the average inbreeding coefficient, of 6.92%. Despite the satisfactory average inbreeding coefficient in recent generations, this coefficient requires monitoring because of its proximity to the recommended limit. Gene flow among herds is the main factor for the increase of effective size and the maintenance of genetic variability in the breed Santa Ines.

Characterization of body biometrics during growth of elite Santa Ines sheep

The objective of this study was to characterize body biometrics of Santa Ines sheep during growth. Data from 4,038 animals, males and females, with ages from four to 36 months, from different herds participating in the National Agricultural Fair in Bahia from 2003 to 2008 were used. The characteristics evaluated were: body weight, average daily gain, body length, thoracic circumference, anterior height and posterior height. The mean values found were compared by the Student-Newman-Keuls test. All characteristics studied showed gradual change with aging, and it is worth-noting that age had positive effect on body weight, body length, thoracic circumference, anterior height and posterior height and negative effect on average daily gain. Average daily gain was reduced by 68.5% from four to 36 months of age, while the mean improvements observed in both sexes in this age range, for body weight, body length, thoracic circumference, anterior height and posterior height were 137.8%, 23.5%, 43.2%, 19.3% and 19.6%, respectively. However, the increments for body weight, body length and thoracic circumference were higher until 12 months of age, when an increase of 72.7%, 14.6% and 24.8% in their respective characteristics was verified. For anterior height and posterior height, the greatest increase occurred up to eight months of age with improvement of 8.4% for both measures. Santa Ines sheep have different growth rates for body measurements; whereas growth in posterior height stabilizes earlier, the thoracic circumference, along with body weight, remains growing for longer time.

Puberty and sexual maturity in Anglo-Nubian male goats raised in semi-intensive system

The objective of this study was to characterize the sexual development in Anglo-Nubian male goats raised in semi-intensive system. Eight animals were monitored every fifteen days, from the 12th to the 44th week for age at penis detachment, live weight, scrotal circumference, seminal parameters (volume, aspect, concentration, wave motion, progressive individual motility, vigor and spermatic abnormalities) and serum testosterone levels. Serum testosterone levels were determined in blood samples collected at the 20th, 28th and 38th weeks of age. Penis detachment occurred at 102.9 ± 15.4 days of age. Live weight and scrotal circumference at 20th and 44th weeks of age ranged from 25.9 ± 3.5 to 44.7 ± 4.7 kg and from 21.2 ± 1.6 cm to 26.0 ± 1.5 cm, respectively. The ejaculate volume ranged from 0.38 ± 0.05 to 0.96 ± 0.04 mL, concentration ranged from 1.33 ± 0.64 to 3.54 ± 0.14.109 mL-1 and the progressive individual motility varied from 48.0 ± 10.52% to 82.0 ± 3.74%, at the same age. The number of defective spermatozoa (major and minor) was 32.2 ± 5.8% vs. 8.80 ± 2.9% at the 20th and the 44th week of age, respectively. Serum testosterone level was 2.70 ± 1.40 ng.mL-1 at the 20th week, 8.50 ± 4.66 ng.mL-1 at the 28th week and 2.21 ± 2.28 ng.mL-1 at the 38th week of age. Age showed a correlation with live weight, scrotal circumference, and all the qualitative parameters of semen except for volume, with all other qualitative parameters of semen, and the correlation among sperm abnormalities and the other traits was negative. Serum testosterone levels and andrological parameters of Anglo-Nubian goats raised in semi-intensive system are closely related to age. In those animals, puberty is reached at the 20th week and sexual maturity is reached at the 38th week of age.

Epidemiology of Eimeria infections in sheep raised extensively in a semiarid region of Brazil

The aim of this study was to identify and determine the prevalence of Eimeria species affecting sheep raised extensively in a semiarid region of Brazil. Fecal samples of native sheep were collected during the rainy and dry seasons. The degree of infection was determined by counting oocysts per gram (OPG) of feces, and the morphometric method was used for species identification. Oocysts were found in all the properties assessed, in which 68.3% of the animals were infected. The prevalence of oocysts was influenced by the season and animal category (P<0.05). It was higher during the rainy season than the dry season (80.2% vs. 55.8%) and highest in young animals than the adults animals (68.2% vs. 39.6%). The OPG was lower during the dry season (1,269 ± 312 vs. 4,400 ± 1,122). Ten species were found; of these, E. ovinoidalis, E. granulosa, E. faurei, and E. crandallis were the most frequent. E. ovinoidalis and E. crandallis were found in all properties, with their prevalences being 19.4% and 13.6% respectively. The high prevalence of pathogenic species shows that eimeriosis is a risk for animals raised extensively in the semiarid region.

Descrição do crescimento de ovinos Santa Inês utilizando modelos não-lineares selecionados por análise multivariada

O objetivo deste estudo foi descrever o crescimento de ovinos Santa Ines utilizando modelos nao-lineares selecionados por analise multivariada. Dezessete modelos nao-lineares foram utilizados para descrever o crescimento de cordeiros do nascimento aos 210 dias de idade. Os modelos foram classificados por meio de analise multivariada utilizando o coeficiente de determinacao ajustado, criterio de informacao de Akaike, criterio de informacao Bayesiano, erro quadratico medio de predicao, coeficiente de determinacao de predicao, desvio medio absoluto dos residuos e percentual de convergencia como avaliadores da qualidade do ajuste. Os modelos Richards, Reynolds e Weibull nao convergiram e os modelos Schnute, Meloun II, IV e VI, Gamito, Michaelis Menten e Michaelis Menten Modificado nao apresentaram padrao de crescimento tradicional. Os modelos Mitscherlich, Gompertz, Logistico, Meloun I, III e V, Brody e Von Bertalanffy convergiram e foram utilizados na analise de agrupamento. Dentre os quatroclusters formados, o primeiro, composto pelos modelos Mitscherlich, Meloun I e Brody, apresentou os melhores valores para os criterio de informacao de Akaike e bayesiano. Os parâmetros da curva foram influenciados pelo sexo e o tipo de parto (P<0,05) e o ponto inflexao ocorreu aos 94 dias de idade. Os modelos Mitscherlich, Meloun I e Brody sao adequados e equivalentes para descricao do crescimento de ovinos Santa Ines.