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Papers by Alan Borges

Revista Brasileira De Zootecnia, 2000

... José Reinaldo Mendes Ruas2, Ciro Alexandre Alves Torres3, Lazáro Eustáquio Borges2, Alberto M... more ... José Reinaldo Mendes Ruas2, Ciro Alexandre Alves Torres3, Lazáro Eustáquio Borges2, Alberto Marcatti Neto2, Galeno Valente Machado4, Álan ... estão apresentadas na Tabela 1. As pastagens eram formadas, predominantemente, por capim-jaraguá (Hyparrhenia rufa spp.) e ...

Revista Brasileira de Ciência Veterinária, 2008

Baseando-se nos mecanismos de interrupção da síntese de PGF 2α em bovinos, objetivou-se com este ... more Baseando-se nos mecanismos de interrupção da síntese de PGF 2α em bovinos, objetivou-se com este estudo avaliar os efeitos do flunixin meglumine (FM) sobre o comprimento do ciclo estral e sobre os níveis de progesterona, em novilhas e vacas mestiças. Após sincronização dos estros, os animais foram divididos em grupos: controle (cinco vacas e quatro novilhas) e tratado (seis vacas e seis novilhas), sendo submetidos à colheita diária de sangue, até o estro subseqüente. Do 13 o ao 18 o dia, aplicou-se nos animais do grupo tratado 1,65 mg/kg intramuscular de FM, e nos do grupo controle, mesmo volume de solução fisiológica. A determinação da concentração sérica de progesterona foi realizada por RIA. Os resultados do comprimento do ciclo estral foram comparados entre os grupos e entre animais, pelo teste t de Student, enquanto a concentração de progesterona foi normalizada em relação à luteólise, e analisada entre os grupos pelo teste t de Tukey (SAS). Não se observou diferença (P>0,05) no comprimento do ciclo estral entre grupos e entre novilhas e vacas, tratadas e não tratadas. O dia do ciclo estral em relação à concentração de progesterona máxima e inferior a 1,0ng/mL, e a concentração sérica de progesterona entre os animais do grupo controle e tratado, também foram semelhantes entre os grupos (P>0,05). No entanto, observou-se diferença (P<0,05) na curva que evidencia a queda da progesterona em relação ao momento da luteólise entre os animais dos grupos experimentais. Conclui-se que, embora se tenha observado efeito do tratamento, como descrito acima, sua ação seria mais bem caracterizada se a população amostral tivesse sido maior.

Animal reproduction, Mar 1, 2016

The in vitro culture conditions for bovine embryos have a fundamental role in the cleavage, embry... more The in vitro culture conditions for bovine embryos have a fundamental role in the cleavage, embryonic genome activation, differentiation and embryo viability (Moore et al., Theriogenology, v.68, p.1316, 2007). Moreover, the female and male gametes co-incubation time has a keyrole in vitro fertilization (IVF) systems. It’s well established that incubation of COCs with 1-1,5x106 spermatozoa/mL sperm concentration, for 18 to 22 hours, produces acceptable embryo produced rates. However, it has also been reported that the gamete incubation time reduction of 18-24 to 10 hours, with low concentration of spermatozoa, is able to produce similar embryonic development rates. Long IVF periods, as well as high sperm concentrations, increase the polyspermy incidence and reduce embryo production (Berland et al., Vet. Science, p.1, 2011). The aim of this study was to evaluate the effect of reducing the time of co-incubation duration at fertilization, on bovine embryo development potential. In vitro matured oocytes were subjected to fertilization with Holstein bull semen, previously tested, using the sperm concentration of 0,3x106 spermatozoa/mL, for 10 or 18 hours of incubation time. The presumptive zygotes were cultured in SOF medium plus BSA and FBS, for seven days. We evaluated the number of matured oocytes pre-insemination, cleavage rate at 72 hours and the blastocysts production in the eighth day after fertilization. To evaluate the oocytes maturation, embryo cleavage and blastocyst production, the contingency analysis by Fisher’s exact test was performed. 1343 oocytes were divided into two incubation times: 10 hours (n = 533) and 18h (n = 810). The COCs maturation rate was 96.6% and 92.2% for the groups 10h and 18h fertilization, respectively (P > 0.05). The cleaved percentage for 10h of incubation group (86.1%) was higher than 18h (79.1%) (P < 0.05). The production of embryos in relation to the total number of cleaved structures was 80.4% and 51.3% for 10h and 18h, respectively (P < 0.05). The blastocysts production rate in relation to the total COCs subjected to in vitro maturation was also superior in 10h of incubation (69.2%) compared with 18h (40.6%) (P < 0.05). It was observed that is possible to obtain higher blastocyst rates using 10 hours of co-incubation duration at in vitro fertilization of bovine oocytes.

Animal reproduction, Mar 1, 2016

We evaluated the effect of the reduction of the natural photoperiod in the state of Minas Gerais ... more We evaluated the effect of the reduction of the natural photoperiod in the state of Minas Gerais (Latitude: 19.93 S, Longitude: 43.93 O) on the rate of in vitro embryo production (IVP) (cleavage and blastocyst) in cattle and buffaloes. According to the length of days, the months of the year were grouped into: unfavorable period for reproduction (October to February), favorable (March to June) and transition (July to September). The oocytes were obtained from slaughterhouse ovaries. Altogether, 153 buffalo oocytes and 662 bovine oocytes were distributed similarly between periods. Oocytes were placed in wash medium (TCM 199, 10% of fetal bovine serum (FBS), 22 μg/mL of sodium pyruvate, 83 ug/mL of amikacin sulfate). They were matured in an incubator (38.5°C, 5% CO2, 95% humidity) for 24 hours in maturation medium (TCM 199 + 10% FCS + 22 ug/mL of pyruvate + 5 IU/mL of LH + 0.05 mg/mL of FSH + 1 ug/mL of estradiol + 83.4 ug/mL of amikacin and 50 mcg/mL of cysteamine) and were then fertilized for 18 to 22 hours. The reagents used were from Sigma-Aldrich, St. Louis, USA. The zygotes were denuded and then cultured in SOF medium (synthetic oviduct fluid) + 2.5% FBS for 7 days. The cleavage rate of embryos cattle and buffalos was assessed between 48 (D2) and 72 (D3) hours after IVF and blastocyst rates were observed 168 (D7) and 192 (D8) after IVF. Statistical analysis was performed using the ANOVA/Duncan or Kruskal-Wallis tests and the level of significance was P 0.05). Comparing the two species at different times, it was found that during favorable season for reproduction, blastocyst rate of buffaloes (47.96 ± 5.01) was higher than that found for bovine (28.91 ± 2.09) (P 0.05). Thus, it is concluded that reducing the photoperiod positively influences IVP in buffaloes; however, at other times of the year production is similar to that of bovine.

Revista Brasileira de Reprodução Animal, Aug 11, 2015

The endometrial cells present changes in defense mechanisms, which consist of immune tolerance to... more The endometrial cells present changes in defense mechanisms, which consist of immune tolerance to allogeneic sperm and fetus, or intolerance to invading microorganisms that contaminate the uterine environment during the copulation or after the parturition. The regulation of the immune response determines the importance of the endometrium to maintain fertility of cows, verifying that exacerbated and/or persistent inflammatory conditions are harmful. The damages arising from subfertility associated with high incidence of uterine diseases stimulate the accomplishment of studies with the aim of understanding the mechanisms involved in immunity of the reproductive tract of women and females of domestic species. The main information will be reported in this review, with focus in dairy cows.

Revista Brasileira de Reprodução Animal, 2011

PLOS ONE, Oct 10, 2019

The mammalian embryo displays sexual dimorphism in the preimplantation period. Moreover, competen... more The mammalian embryo displays sexual dimorphism in the preimplantation period. Moreover, competence of the embryo to develop is dependent on the sire from which the embryo is derived and can be modified by embryokines produced by the endometrium such as colony stimulating factor 2 (CSF2). The preimplantation period is characterized by large changes in epigenetic modifications of DNA and histones. It is possible, therefore, that effects of sex, sire, and embryo regulatory molecules are mediated by changes in epigenetic modifications. Here it was tested whether global levels of two histone modifications in the trophectoderm of the bovine blastocyst were affected by sex, sire, and CSF2. It was found that amounts of immunolabeled H3K27me3 were greater (P = 0.030) for male embryos than female embryos. Additionally, labeling for H3K27me3 and H3K18ac depended upon the bull from which embryos were derived. Although CSF2 reduced the proportion of embryos developing to the blastocyst, there was no effect of CSF2 on labeling for H3K27me3 or H3K18ac. Results indicate that the blastocyst trophoctoderm can be modified epigenetically by embryo sex and paternal inheritance through alterations in histone epigenetic marks.

Revista Brasileira de Ciência Veterinária, 2008

Taxa de concepção de éguas submetidas a duas frequências de palpação retal (24 e 12 horas) e cobe... more Taxa de concepção de éguas submetidas a duas frequências de palpação retal (24 e 12 horas) e cobertas após a ovulação Conception rate of mares controlled by two rectal palpation intervals (24 or 12 h) and breeding after ovulation

Revista Brasileira de Reprodução Animal, 2016

Animal reproduction, Mar 1, 2016

This study aims to investigate the effect of different protocols of follicular wave synchronizati... more This study aims to investigate the effect of different protocols of follicular wave synchronization of bubaline oocytes donor regarding the number of follicles, the recovery rate, the number and quality of oocytes produced. 12 adult buffallo were used under different protocols that resulted in the aspiration of follicles guided by ultrasound (OPU) 3 to 4 days after the emergence of follicular wave. Each animal was tested at least three times for each treatment. The treatments were: Treatment 1 (T1): animals not filed with OPU held in random day of the estrous cycle; Treatment 2 (T2): follicular wave reset prior to aspiration of all ovarian follicles, performing the OPU 3-4 days later; Treatment 3 (T3): placement of intravaginal progesterone device for 6 days, together with 2 mg of estradiol benzoate, 50 mg of progesterone and 150μg of prostaglandin, the OPU done at the implant removal; Treatment 4 (T4): similar to T3, however, T4 was applied, 100mg of FSH, 36-48 hours prior to OPU. At the OPU procedure, animals were evaluated for the number and size of follicles, classifying them into small (2-5mm), medium (6-9mm) and large (≥9mm). After collection, the oocytes were processed and classified according to morphological characteristics: Grade A, Grade B, Grade C, Grade D, expanded or naked. Statistical analysis was performed under ANOVA / Duncan test or KruskalWallis test and the significance level was P 0.05); but it was lower than T3 (10.44 ± 0,92b) and T4 (b- 11.39 ± 0.67 P 0.05) between treatments. The synchronization treatments using hormones (T3, T4) or not (T2) did not alter the average number of follicles, as they did not differ from T1 (P > 0.05). There was no difference between the total number of follicles observed at the moment of OPU and between different treatments (P > 0.05). However, comparing the number of follicles between the same treatments, we noticed a higher number of small follicles in relation to medium and large follicles (P < 0.05). It was concluded that the proposed protocols were not efficient to improve the number and quality of the OPU recovered structures.

Veterinária em Foco, Jan 16, 2008

Since two decades, the main advances have been carried out on identification of peptides that are... more Since two decades, the main advances have been carried out on identification of peptides that are produced or localized in the hypothalamus and play a role in the energy homeostatic process. With regard to this, ghrelin, a 28-aminoacids orexigen peptide, is involved in the control of feed intake and in the growth hormone secretion, leading to new understanding about the existence of hypothalamic-pituitary-gastric axis that provide homeostasis endocrine control through the growth hormone (GH) secretion and intestinal motility. Reproductive axis is highly dependent of nutritional status, thus, ghrelin acting central and peripherically, may be one of the mediators of nutritional status to the hypothalamic-pituitary-gonadal axis. Ghrelin reproductive action is not, apparently, restrict to its expression and direct action on the gonads. Extra-gonadal actions within reproductive axis also have been reported, although data are rare. Thus, ghrelin isolation and characterization have made possible the understanding of anabolism and intake behavior physiology, and nutritional homeostasis linked to reproduction, through growth hormone (GH) secretion and gastrointestinal motility that interact with brain.

Informe Agropecuario, 2010

Revista Brasileira de Ciência Veterinária, 2009

A produção in vivo de embriões bovinos é uma alternativa para a formação e manutenção de rebanhos... more A produção in vivo de embriões bovinos é uma alternativa para a formação e manutenção de rebanhos mestiços F1 destinados à produção de leite. Objetivou-se estudar o potencial de utilização de novilhas da raça Holandês, mantidas em pasto e suplementadas, como doadoras de embrião, nas épocas de verão e inverno. Procederam-se superovulação e coleta de embriões em sete novilhas em cada época. Foram obtidos os dados climáticos, a temperatura retal e a frequência respiratória das doadoras. No verão, observou-se maior índice de temperatura e umidade (ITU) às 6h, 12h e 18h, bem como maior (P<0,05) temperatura retal das doadoras às 18h. A porcentagem de animais que respondeu à superovulação foi de 71,4% (5/7) no inverno e 85,7% (6/7) no verão. O número total de estruturas recuperadas por doadora variou de um a 49 no inverno, e de zero a 23 no verão. Não houve diferença (P>0,05) na média de estruturas recuperadas (20,14±17,47 vs. 8,57±9,40), embriões viáveis (14,57±11,91 vs. 7,14±7,24) e congeláveis (13,28±11,39 vs. 6,57±6,24) obtidos no inverno e no verão, respectivamente. Sob as condições estudadas, novilhas da raça Holandês podem ser utilizadas para a produção de embriões F1, tanto no verão, quanto no inverno. Palavras-chave: transferência de embriões, novilhas, época do ano, superovulação.

Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, Apr 1, 2012

The aim of this study was to verify the efficacy of reusing intravaginal progesterone (P4) device... more The aim of this study was to verify the efficacy of reusing intravaginal progesterone (P4) devices on the reproductive parameters in Santa Inês ewes. Females received intravaginal P4 devices for their first, second or third use for five days plus 300 IU eCG IM and 5mg dinoprost laterovulvar 24h before device removal. Blood was collected at different moments. Transrectal ultrasonography was performed from device removal to ovulation. Part of the ewes were submitted to artificial insemination by laparoscopy (IAL-n=55) with fresh semen, whereas the rest were bred by fertile rams (n=41). On the initial 18 h, ewes that received devices for the first time showed higher P4 concentrations (5.1±1.8 vs 3.5±1.4 vs 2.4±1.1-P<0.05). However, after the first 48h no difference was observed among all treatments and P4 supraluteal concentrations were detected in all ewes upon device removal. Estrous response, interval from device removal to estrus, rate of ovulating animals, number of ovulations, time from device removal to ovulation and average conception rates after IAL or natural mating were similar among all 3 groups. Intravaginal progesterone devices can be used up to three times without altering reproductive parameters in Santa Inês ewes.

Veterinary Pathology, Sep 1, 2005

Although visceral leishmaniasis is primarily transmitted by a biological invertebrate vector, tra... more Although visceral leishmaniasis is primarily transmitted by a biological invertebrate vector, transmission in the absence of the vector has been reported, including venereal transmission in humans. Considering the possibility of venereal transmission, we studied genital lesions in dogs naturally infected with visceral leishmaniasis and shedding of Leishmania sp. in the semen. Approximately 200 dogs were serologically tested for anti-Leishmania antibodies and divided into three groups: 1) serologically negative dogs (n ϭ 20), 2) asymptomatic serologically positive dogs (n ϭ 20), and 3) symptomatic serologically positive dogs (n ϭ 20). Samples from both testes, all segments of both epididymes, prostate gland, glans penis, and prepuce were histologically evaluated and processed for immunodetection of Leishmania sp. Semen samples were obtained from 22 symptomatic serologically positive dogs and processed for detecting Leishmania DNA by polymerase chain reaction. A significantly higher frequency of inflammation was observed in the epididymes, glans penis, and prepuce of dogs with visceral leishmaniasis, which was associated with a high frequency of immunohistochemically positive tissues (up to 95% of tissues from symptomatic dogs were positive by immunohistochemistry). Leishmania DNA was detected in eight of 22 semen samples from symptomatic dogs. Together these findings indicate that genital lesions and shedding of Leishmania sp. (donovani complex) in the semen are associated with visceral leishmaniasis. Additional studies should address the possibility of venereal transmission of the disease in the dog.

Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, Feb 1, 2009

Taxa de concepção de cabras inseminadas com sêmen caprino resfriado a 5 o C, por 12 ou 24 horas, ... more Taxa de concepção de cabras inseminadas com sêmen caprino resfriado a 5 o C, por 12 ou 24 horas, em meio diluidor à base de gema de ovo [Conception rate of goats inseminated with semen cooled in egg yolk diluent at 5 o C, for 12 or 24 hours]

Animal reproduction, Mar 1, 2015

In vitro produced embryos exhibit low cryotolerance due to their high concentration of cytoplasmi... more In vitro produced embryos exhibit low cryotolerance due to their high concentration of cytoplasmic lipids (Abe et al., J. Reprod. Dev., v.49, p.193, 2003). The conjugated linoleic acid trans-10, cis-12 (CLA) decrease lipogenesis in cells, improving embryo quality and possibly decreasing its sensitivity to cryopreservation (Mitchell and McLeod, Biochem. Cell Biol., v.86, p.293, 2008). It was evaluated the effect of adding CLA to in vitro culture medium in the viability after vitrified bovine embryo transfer. Three culture media were used: Control (n=340 oocytes): SOF medium added to BSA and FBS, without the addition of CLA; FBS+CLA (n=359 oocytes): SOF medium added to BSA, FBS and CLA; CLA (n=339 oocytes): SOF medium plus BSA added to CLA, without adding FBS. The blastocysts were submitted to the Open Pulled Straw vitrification method for subsequent heating. The recipient estrus was synchronized using protocol with intravaginal progesterone device (1.9g), associated with estradiol benzoate (2.0 mg) and estradiol cypionate (1mg), eCG (250UI) and analog PF2α (0.05 mg of sodium cloprostenol). There were transferred one or two embryos to the uterine horn ipsilateral to the corpus luteum (CL): T1 [recipients that received one blastocyst (n=17 embryos, Control=5, FBS+CLA=6 and CLA=6)]; T2 [recipients that received two blastocysts (n =54 embryos, Control=18, FBS+CLA=14 and CLA=22)]. In D7 after induced estrus the recipients were evaluated for CL confirmation. 58% of the animals responded with exacerbated form to estrus induction protocol, with multiple ovulations (2 to 7 CLs) and multifollicular growth (follicles up to 1.9cm and follicles larger than 2.0cm). The embryo transfer was performed only on animals with CL and follicles smaller than 1.9cm. To assess viability, vitrified embryos were heated (Control=27; FBS+CLA=30; CLA=17) and cultured in vitro to verify the reexpansion and hatching ability after 24, 48 and 72 hours of cultivation. There was no difference in blastocyst production relative to the total number of oocytes fertilization (37.1% for Control; 35.4% for FBS + CLA, CLA and 28.3%) (P>0.05). Only one pregnancy was observed in early and confirmatory diagnosis, result of a Control group embryo transfer. Pregnancy rates for Control group, FBS+CLA and CLA were, respectively, 4.35% (1/23), 0% (0/20) and 0% (0/28). Regarding the reexpansion, CLA treatment (47.1%) had lower rate (P 0.05) by looking up 42.1%; 23.1%; 25% for Control; FBS+CLA; CLA groups, respectively. New embryo transfers should be carried out to evaluate the effect of CLA on in vivo embryo survival, endorsing the in vitro obtained reexpansion and hatching rates.

Reproduction, Fertility and Development, 2010

Revista Brasileira de Reprodução Animal, Aug 11, 2015

The challenge of milk producers in Brazil is to find the balance between production and sustainab... more The challenge of milk producers in Brazil is to find the balance between production and sustainability of milk production systems. Approximately 70% of Brazilian dairy herds consists in crossbreeding Holstein x Zebu cows, which are kept in semi-intensive management system. Basic and applied researches aimed at understanding the particularities about the productive and reproductive physiology of dairy crossbred females are extremely important to help increase the performance of these animals, considering the reality of dairy farming in our country. This review aims to present data about potential of production and reproduction of crossbred Holstein x Zebu dairy cows, and the challenges to improve their performance.

Revista Brasileira De Zootecnia, 2000

... José Reinaldo Mendes Ruas2, Ciro Alexandre Alves Torres3, Lazáro Eustáquio Borges2, Alberto M... more ... José Reinaldo Mendes Ruas2, Ciro Alexandre Alves Torres3, Lazáro Eustáquio Borges2, Alberto Marcatti Neto2, Galeno Valente Machado4, Álan ... estão apresentadas na Tabela 1. As pastagens eram formadas, predominantemente, por capim-jaraguá (Hyparrhenia rufa spp.) e ...

Revista Brasileira de Ciência Veterinária, 2008

Baseando-se nos mecanismos de interrupção da síntese de PGF 2α em bovinos, objetivou-se com este ... more Baseando-se nos mecanismos de interrupção da síntese de PGF 2α em bovinos, objetivou-se com este estudo avaliar os efeitos do flunixin meglumine (FM) sobre o comprimento do ciclo estral e sobre os níveis de progesterona, em novilhas e vacas mestiças. Após sincronização dos estros, os animais foram divididos em grupos: controle (cinco vacas e quatro novilhas) e tratado (seis vacas e seis novilhas), sendo submetidos à colheita diária de sangue, até o estro subseqüente. Do 13 o ao 18 o dia, aplicou-se nos animais do grupo tratado 1,65 mg/kg intramuscular de FM, e nos do grupo controle, mesmo volume de solução fisiológica. A determinação da concentração sérica de progesterona foi realizada por RIA. Os resultados do comprimento do ciclo estral foram comparados entre os grupos e entre animais, pelo teste t de Student, enquanto a concentração de progesterona foi normalizada em relação à luteólise, e analisada entre os grupos pelo teste t de Tukey (SAS). Não se observou diferença (P>0,05) no comprimento do ciclo estral entre grupos e entre novilhas e vacas, tratadas e não tratadas. O dia do ciclo estral em relação à concentração de progesterona máxima e inferior a 1,0ng/mL, e a concentração sérica de progesterona entre os animais do grupo controle e tratado, também foram semelhantes entre os grupos (P>0,05). No entanto, observou-se diferença (P<0,05) na curva que evidencia a queda da progesterona em relação ao momento da luteólise entre os animais dos grupos experimentais. Conclui-se que, embora se tenha observado efeito do tratamento, como descrito acima, sua ação seria mais bem caracterizada se a população amostral tivesse sido maior.

Animal reproduction, Mar 1, 2016

The in vitro culture conditions for bovine embryos have a fundamental role in the cleavage, embry... more The in vitro culture conditions for bovine embryos have a fundamental role in the cleavage, embryonic genome activation, differentiation and embryo viability (Moore et al., Theriogenology, v.68, p.1316, 2007). Moreover, the female and male gametes co-incubation time has a keyrole in vitro fertilization (IVF) systems. It’s well established that incubation of COCs with 1-1,5x106 spermatozoa/mL sperm concentration, for 18 to 22 hours, produces acceptable embryo produced rates. However, it has also been reported that the gamete incubation time reduction of 18-24 to 10 hours, with low concentration of spermatozoa, is able to produce similar embryonic development rates. Long IVF periods, as well as high sperm concentrations, increase the polyspermy incidence and reduce embryo production (Berland et al., Vet. Science, p.1, 2011). The aim of this study was to evaluate the effect of reducing the time of co-incubation duration at fertilization, on bovine embryo development potential. In vitro matured oocytes were subjected to fertilization with Holstein bull semen, previously tested, using the sperm concentration of 0,3x106 spermatozoa/mL, for 10 or 18 hours of incubation time. The presumptive zygotes were cultured in SOF medium plus BSA and FBS, for seven days. We evaluated the number of matured oocytes pre-insemination, cleavage rate at 72 hours and the blastocysts production in the eighth day after fertilization. To evaluate the oocytes maturation, embryo cleavage and blastocyst production, the contingency analysis by Fisher’s exact test was performed. 1343 oocytes were divided into two incubation times: 10 hours (n = 533) and 18h (n = 810). The COCs maturation rate was 96.6% and 92.2% for the groups 10h and 18h fertilization, respectively (P > 0.05). The cleaved percentage for 10h of incubation group (86.1%) was higher than 18h (79.1%) (P < 0.05). The production of embryos in relation to the total number of cleaved structures was 80.4% and 51.3% for 10h and 18h, respectively (P < 0.05). The blastocysts production rate in relation to the total COCs subjected to in vitro maturation was also superior in 10h of incubation (69.2%) compared with 18h (40.6%) (P < 0.05). It was observed that is possible to obtain higher blastocyst rates using 10 hours of co-incubation duration at in vitro fertilization of bovine oocytes.

Animal reproduction, Mar 1, 2016

We evaluated the effect of the reduction of the natural photoperiod in the state of Minas Gerais ... more We evaluated the effect of the reduction of the natural photoperiod in the state of Minas Gerais (Latitude: 19.93 S, Longitude: 43.93 O) on the rate of in vitro embryo production (IVP) (cleavage and blastocyst) in cattle and buffaloes. According to the length of days, the months of the year were grouped into: unfavorable period for reproduction (October to February), favorable (March to June) and transition (July to September). The oocytes were obtained from slaughterhouse ovaries. Altogether, 153 buffalo oocytes and 662 bovine oocytes were distributed similarly between periods. Oocytes were placed in wash medium (TCM 199, 10% of fetal bovine serum (FBS), 22 μg/mL of sodium pyruvate, 83 ug/mL of amikacin sulfate). They were matured in an incubator (38.5°C, 5% CO2, 95% humidity) for 24 hours in maturation medium (TCM 199 + 10% FCS + 22 ug/mL of pyruvate + 5 IU/mL of LH + 0.05 mg/mL of FSH + 1 ug/mL of estradiol + 83.4 ug/mL of amikacin and 50 mcg/mL of cysteamine) and were then fertilized for 18 to 22 hours. The reagents used were from Sigma-Aldrich, St. Louis, USA. The zygotes were denuded and then cultured in SOF medium (synthetic oviduct fluid) + 2.5% FBS for 7 days. The cleavage rate of embryos cattle and buffalos was assessed between 48 (D2) and 72 (D3) hours after IVF and blastocyst rates were observed 168 (D7) and 192 (D8) after IVF. Statistical analysis was performed using the ANOVA/Duncan or Kruskal-Wallis tests and the level of significance was P 0.05). Comparing the two species at different times, it was found that during favorable season for reproduction, blastocyst rate of buffaloes (47.96 ± 5.01) was higher than that found for bovine (28.91 ± 2.09) (P 0.05). Thus, it is concluded that reducing the photoperiod positively influences IVP in buffaloes; however, at other times of the year production is similar to that of bovine.

Revista Brasileira de Reprodução Animal, Aug 11, 2015

The endometrial cells present changes in defense mechanisms, which consist of immune tolerance to... more The endometrial cells present changes in defense mechanisms, which consist of immune tolerance to allogeneic sperm and fetus, or intolerance to invading microorganisms that contaminate the uterine environment during the copulation or after the parturition. The regulation of the immune response determines the importance of the endometrium to maintain fertility of cows, verifying that exacerbated and/or persistent inflammatory conditions are harmful. The damages arising from subfertility associated with high incidence of uterine diseases stimulate the accomplishment of studies with the aim of understanding the mechanisms involved in immunity of the reproductive tract of women and females of domestic species. The main information will be reported in this review, with focus in dairy cows.

Revista Brasileira de Reprodução Animal, 2011

PLOS ONE, Oct 10, 2019

The mammalian embryo displays sexual dimorphism in the preimplantation period. Moreover, competen... more The mammalian embryo displays sexual dimorphism in the preimplantation period. Moreover, competence of the embryo to develop is dependent on the sire from which the embryo is derived and can be modified by embryokines produced by the endometrium such as colony stimulating factor 2 (CSF2). The preimplantation period is characterized by large changes in epigenetic modifications of DNA and histones. It is possible, therefore, that effects of sex, sire, and embryo regulatory molecules are mediated by changes in epigenetic modifications. Here it was tested whether global levels of two histone modifications in the trophectoderm of the bovine blastocyst were affected by sex, sire, and CSF2. It was found that amounts of immunolabeled H3K27me3 were greater (P = 0.030) for male embryos than female embryos. Additionally, labeling for H3K27me3 and H3K18ac depended upon the bull from which embryos were derived. Although CSF2 reduced the proportion of embryos developing to the blastocyst, there was no effect of CSF2 on labeling for H3K27me3 or H3K18ac. Results indicate that the blastocyst trophoctoderm can be modified epigenetically by embryo sex and paternal inheritance through alterations in histone epigenetic marks.

Revista Brasileira de Ciência Veterinária, 2008

Taxa de concepção de éguas submetidas a duas frequências de palpação retal (24 e 12 horas) e cobe... more Taxa de concepção de éguas submetidas a duas frequências de palpação retal (24 e 12 horas) e cobertas após a ovulação Conception rate of mares controlled by two rectal palpation intervals (24 or 12 h) and breeding after ovulation

Revista Brasileira de Reprodução Animal, 2016

Animal reproduction, Mar 1, 2016

This study aims to investigate the effect of different protocols of follicular wave synchronizati... more This study aims to investigate the effect of different protocols of follicular wave synchronization of bubaline oocytes donor regarding the number of follicles, the recovery rate, the number and quality of oocytes produced. 12 adult buffallo were used under different protocols that resulted in the aspiration of follicles guided by ultrasound (OPU) 3 to 4 days after the emergence of follicular wave. Each animal was tested at least three times for each treatment. The treatments were: Treatment 1 (T1): animals not filed with OPU held in random day of the estrous cycle; Treatment 2 (T2): follicular wave reset prior to aspiration of all ovarian follicles, performing the OPU 3-4 days later; Treatment 3 (T3): placement of intravaginal progesterone device for 6 days, together with 2 mg of estradiol benzoate, 50 mg of progesterone and 150μg of prostaglandin, the OPU done at the implant removal; Treatment 4 (T4): similar to T3, however, T4 was applied, 100mg of FSH, 36-48 hours prior to OPU. At the OPU procedure, animals were evaluated for the number and size of follicles, classifying them into small (2-5mm), medium (6-9mm) and large (≥9mm). After collection, the oocytes were processed and classified according to morphological characteristics: Grade A, Grade B, Grade C, Grade D, expanded or naked. Statistical analysis was performed under ANOVA / Duncan test or KruskalWallis test and the significance level was P 0.05); but it was lower than T3 (10.44 ± 0,92b) and T4 (b- 11.39 ± 0.67 P 0.05) between treatments. The synchronization treatments using hormones (T3, T4) or not (T2) did not alter the average number of follicles, as they did not differ from T1 (P > 0.05). There was no difference between the total number of follicles observed at the moment of OPU and between different treatments (P > 0.05). However, comparing the number of follicles between the same treatments, we noticed a higher number of small follicles in relation to medium and large follicles (P < 0.05). It was concluded that the proposed protocols were not efficient to improve the number and quality of the OPU recovered structures.

Veterinária em Foco, Jan 16, 2008

Since two decades, the main advances have been carried out on identification of peptides that are... more Since two decades, the main advances have been carried out on identification of peptides that are produced or localized in the hypothalamus and play a role in the energy homeostatic process. With regard to this, ghrelin, a 28-aminoacids orexigen peptide, is involved in the control of feed intake and in the growth hormone secretion, leading to new understanding about the existence of hypothalamic-pituitary-gastric axis that provide homeostasis endocrine control through the growth hormone (GH) secretion and intestinal motility. Reproductive axis is highly dependent of nutritional status, thus, ghrelin acting central and peripherically, may be one of the mediators of nutritional status to the hypothalamic-pituitary-gonadal axis. Ghrelin reproductive action is not, apparently, restrict to its expression and direct action on the gonads. Extra-gonadal actions within reproductive axis also have been reported, although data are rare. Thus, ghrelin isolation and characterization have made possible the understanding of anabolism and intake behavior physiology, and nutritional homeostasis linked to reproduction, through growth hormone (GH) secretion and gastrointestinal motility that interact with brain.

Informe Agropecuario, 2010

Revista Brasileira de Ciência Veterinária, 2009

A produção in vivo de embriões bovinos é uma alternativa para a formação e manutenção de rebanhos... more A produção in vivo de embriões bovinos é uma alternativa para a formação e manutenção de rebanhos mestiços F1 destinados à produção de leite. Objetivou-se estudar o potencial de utilização de novilhas da raça Holandês, mantidas em pasto e suplementadas, como doadoras de embrião, nas épocas de verão e inverno. Procederam-se superovulação e coleta de embriões em sete novilhas em cada época. Foram obtidos os dados climáticos, a temperatura retal e a frequência respiratória das doadoras. No verão, observou-se maior índice de temperatura e umidade (ITU) às 6h, 12h e 18h, bem como maior (P<0,05) temperatura retal das doadoras às 18h. A porcentagem de animais que respondeu à superovulação foi de 71,4% (5/7) no inverno e 85,7% (6/7) no verão. O número total de estruturas recuperadas por doadora variou de um a 49 no inverno, e de zero a 23 no verão. Não houve diferença (P>0,05) na média de estruturas recuperadas (20,14±17,47 vs. 8,57±9,40), embriões viáveis (14,57±11,91 vs. 7,14±7,24) e congeláveis (13,28±11,39 vs. 6,57±6,24) obtidos no inverno e no verão, respectivamente. Sob as condições estudadas, novilhas da raça Holandês podem ser utilizadas para a produção de embriões F1, tanto no verão, quanto no inverno. Palavras-chave: transferência de embriões, novilhas, época do ano, superovulação.

Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, Apr 1, 2012

The aim of this study was to verify the efficacy of reusing intravaginal progesterone (P4) device... more The aim of this study was to verify the efficacy of reusing intravaginal progesterone (P4) devices on the reproductive parameters in Santa Inês ewes. Females received intravaginal P4 devices for their first, second or third use for five days plus 300 IU eCG IM and 5mg dinoprost laterovulvar 24h before device removal. Blood was collected at different moments. Transrectal ultrasonography was performed from device removal to ovulation. Part of the ewes were submitted to artificial insemination by laparoscopy (IAL-n=55) with fresh semen, whereas the rest were bred by fertile rams (n=41). On the initial 18 h, ewes that received devices for the first time showed higher P4 concentrations (5.1±1.8 vs 3.5±1.4 vs 2.4±1.1-P<0.05). However, after the first 48h no difference was observed among all treatments and P4 supraluteal concentrations were detected in all ewes upon device removal. Estrous response, interval from device removal to estrus, rate of ovulating animals, number of ovulations, time from device removal to ovulation and average conception rates after IAL or natural mating were similar among all 3 groups. Intravaginal progesterone devices can be used up to three times without altering reproductive parameters in Santa Inês ewes.

Veterinary Pathology, Sep 1, 2005

Although visceral leishmaniasis is primarily transmitted by a biological invertebrate vector, tra... more Although visceral leishmaniasis is primarily transmitted by a biological invertebrate vector, transmission in the absence of the vector has been reported, including venereal transmission in humans. Considering the possibility of venereal transmission, we studied genital lesions in dogs naturally infected with visceral leishmaniasis and shedding of Leishmania sp. in the semen. Approximately 200 dogs were serologically tested for anti-Leishmania antibodies and divided into three groups: 1) serologically negative dogs (n ϭ 20), 2) asymptomatic serologically positive dogs (n ϭ 20), and 3) symptomatic serologically positive dogs (n ϭ 20). Samples from both testes, all segments of both epididymes, prostate gland, glans penis, and prepuce were histologically evaluated and processed for immunodetection of Leishmania sp. Semen samples were obtained from 22 symptomatic serologically positive dogs and processed for detecting Leishmania DNA by polymerase chain reaction. A significantly higher frequency of inflammation was observed in the epididymes, glans penis, and prepuce of dogs with visceral leishmaniasis, which was associated with a high frequency of immunohistochemically positive tissues (up to 95% of tissues from symptomatic dogs were positive by immunohistochemistry). Leishmania DNA was detected in eight of 22 semen samples from symptomatic dogs. Together these findings indicate that genital lesions and shedding of Leishmania sp. (donovani complex) in the semen are associated with visceral leishmaniasis. Additional studies should address the possibility of venereal transmission of the disease in the dog.

Arquivo Brasileiro De Medicina Veterinaria E Zootecnia, Feb 1, 2009

Taxa de concepção de cabras inseminadas com sêmen caprino resfriado a 5 o C, por 12 ou 24 horas, ... more Taxa de concepção de cabras inseminadas com sêmen caprino resfriado a 5 o C, por 12 ou 24 horas, em meio diluidor à base de gema de ovo [Conception rate of goats inseminated with semen cooled in egg yolk diluent at 5 o C, for 12 or 24 hours]

Animal reproduction, Mar 1, 2015

In vitro produced embryos exhibit low cryotolerance due to their high concentration of cytoplasmi... more In vitro produced embryos exhibit low cryotolerance due to their high concentration of cytoplasmic lipids (Abe et al., J. Reprod. Dev., v.49, p.193, 2003). The conjugated linoleic acid trans-10, cis-12 (CLA) decrease lipogenesis in cells, improving embryo quality and possibly decreasing its sensitivity to cryopreservation (Mitchell and McLeod, Biochem. Cell Biol., v.86, p.293, 2008). It was evaluated the effect of adding CLA to in vitro culture medium in the viability after vitrified bovine embryo transfer. Three culture media were used: Control (n=340 oocytes): SOF medium added to BSA and FBS, without the addition of CLA; FBS+CLA (n=359 oocytes): SOF medium added to BSA, FBS and CLA; CLA (n=339 oocytes): SOF medium plus BSA added to CLA, without adding FBS. The blastocysts were submitted to the Open Pulled Straw vitrification method for subsequent heating. The recipient estrus was synchronized using protocol with intravaginal progesterone device (1.9g), associated with estradiol benzoate (2.0 mg) and estradiol cypionate (1mg), eCG (250UI) and analog PF2α (0.05 mg of sodium cloprostenol). There were transferred one or two embryos to the uterine horn ipsilateral to the corpus luteum (CL): T1 [recipients that received one blastocyst (n=17 embryos, Control=5, FBS+CLA=6 and CLA=6)]; T2 [recipients that received two blastocysts (n =54 embryos, Control=18, FBS+CLA=14 and CLA=22)]. In D7 after induced estrus the recipients were evaluated for CL confirmation. 58% of the animals responded with exacerbated form to estrus induction protocol, with multiple ovulations (2 to 7 CLs) and multifollicular growth (follicles up to 1.9cm and follicles larger than 2.0cm). The embryo transfer was performed only on animals with CL and follicles smaller than 1.9cm. To assess viability, vitrified embryos were heated (Control=27; FBS+CLA=30; CLA=17) and cultured in vitro to verify the reexpansion and hatching ability after 24, 48 and 72 hours of cultivation. There was no difference in blastocyst production relative to the total number of oocytes fertilization (37.1% for Control; 35.4% for FBS + CLA, CLA and 28.3%) (P>0.05). Only one pregnancy was observed in early and confirmatory diagnosis, result of a Control group embryo transfer. Pregnancy rates for Control group, FBS+CLA and CLA were, respectively, 4.35% (1/23), 0% (0/20) and 0% (0/28). Regarding the reexpansion, CLA treatment (47.1%) had lower rate (P 0.05) by looking up 42.1%; 23.1%; 25% for Control; FBS+CLA; CLA groups, respectively. New embryo transfers should be carried out to evaluate the effect of CLA on in vivo embryo survival, endorsing the in vitro obtained reexpansion and hatching rates.

Reproduction, Fertility and Development, 2010

Revista Brasileira de Reprodução Animal, Aug 11, 2015

The challenge of milk producers in Brazil is to find the balance between production and sustainab... more The challenge of milk producers in Brazil is to find the balance between production and sustainability of milk production systems. Approximately 70% of Brazilian dairy herds consists in crossbreeding Holstein x Zebu cows, which are kept in semi-intensive management system. Basic and applied researches aimed at understanding the particularities about the productive and reproductive physiology of dairy crossbred females are extremely important to help increase the performance of these animals, considering the reality of dairy farming in our country. This review aims to present data about potential of production and reproduction of crossbred Holstein x Zebu dairy cows, and the challenges to improve their performance.