Anibal Nascimento - Academia.edu (original) (raw)

Papers by Anibal Nascimento

Ovarian function, steroid hormones and fertility in cows stimulated with

Reproduction, Fertility and Development, 2005

Butyrolactone I and cycloheximide specifically inhibit MPF activation and prevent the resumption ... more Butyrolactone I and cycloheximide specifically inhibit MPF activation and prevent the resumption of meiosis. The aim of this study was to investigate the kinetics of in vitro maturation of butyrolactone I- and cycloheximide-treated swine oocytes in an attempt to produce cytoplasts for nuclear transfer. Oocytes from slaughterhouse ovaries were randomly allotted to one of 3 treatments; group 1 (n = 102 – control – 22 hours of in vitro maturation in TCM199 supplemented with 3.05 mM glucose, 0.91 mM sodium pyruvate, 10% follicular fluid, 0.57 mM cysteine, 10 ng/mL EGF, 10 IU/mL eCG and 10 IU/mL of hCG and 22 hours of culture); Group 2 (n = 191 – blocking for 10 hours in 12.5 M butyrolactone I and in vitro maturation for 44 hours); and Group 3 (n = 175 – blocking for 10 hours in 5 M cyclohexemide and in vitro maturation for 44 hours). After in vitro maturation, oocytes were fixed and stained for evaluation of meiotic division. The percentage of oocytes at metaphase II (MII) in Groups 1 a...

Reproduction, Fertility and Development, 2006

The present work evaluated the reversible meiosis inhibition effect on the development of swine e... more The present work evaluated the reversible meiosis inhibition effect on the development of swine embryos produced by in vitro fertilization (IVF) or parthenogenetic activation (PA). The efficiency of PZM3 and NCSU23 embryo culture media was also evaluated. Oocytes from ovaries collected at a slaughterhouse were subjected to IVM in two different groups: CHX (cycloheximide 5 µM for 10 h) and control, both with TCM-199 + 3.05 mM glucose + 0.91 mM sodium pyruvate + 10% porcine follicular fluid (pFF) + 0.57 mM cystein + 10 ng epidermal growth factor (EGF)/mL + 10 IU eCG/mL + 10 IU hCG/mL for the initial 22 h. In the remaining period (20 h for CHX and 22 h for control), medium without hormones was utilized. After IVM, oocytes were denuded and fertilized for 6 h (IFV) or the matured oocytes were submitted to activation by electric pulses (PA) (2 DC of 1.5 kV/cm for 30 µs), incubated for 1 h in culture medium with 10 μM of CHX, and again submitted to the same electric pulses for 60 µs. Embry...

Biology of Reproduction, 2010

Biology of Reproduction, 2011

Reproduction, Fertility and Development, 2014

Testosterone metabolism occurs primarily in the liver, and circulating concentrations can be infl... more Testosterone metabolism occurs primarily in the liver, and circulating concentrations can be influenced by the amount and type of diet provided. Furthermore, there are reports of the influence of circadian rhythms on secretion of testosterone in ruminants. Based on evidence that supplementation with rumen-protected fat may increase circulating concentrations of steroid hormones (Guardieiro et al. 2010 Pesq. Agrop. Bras. 45, 408–414), this study aimed to evaluate the effect of the addition of rumen-protected fat, antioxidants, or both to the diet on serum testosterone concentration in bulls, and to assess whether there is variation in hormone concentrations at different times of the day after feeding. Forty-eight Nelore bulls were confined and assigned to four treatment groups according to the addition of rumen-protected fat, antioxidants, or both to the standard diet (sugarcane bagasse, citrus pulp, corn gluten meal, urea, and mineral salt): F) rumen-protected polyunsaturated fatty ...

Journal of dairy science, 2012

Ovulation to the first GnRH injection of Ovsynch-type protocols is lower in cows with high proges... more Ovulation to the first GnRH injection of Ovsynch-type protocols is lower in cows with high progesterone (P4) concentrations compared with cows with low P4 concentrations, suggesting that P4 may suppress the release of LH from the anterior pituitary after GnRH treatment. The objectives of this study were to determine the effect of 1) circulating P4 concentrations at the time of GnRH treatment on GnRH-induced LH secretion in lactating dairy cows and 2) increasing the dose of GnRH from 100 to 200 μg on LH secretion in a high- and low-P4 environment. A Double-Ovsynch (Pre-Ovsynch: GnRH, PGF(2α) 7d later, GnRH 3d later, and Breeding-Ovsynch 7d later: GnRH, PGF(2α) 7d later, and GnRH 48 h later) synchronization protocol was used to create the high- and low-P4 environments. At the first GnRH injection of Breeding-Ovsynch (high P4), all cows with a corpus luteum ≥ 20 mm were randomly assigned to receive 100 or 200 μg of GnRH. At the second GnRH injection of Breeding-Ovsynch (low P4) cows we...

Journal of dairy science, 2013

Reproductive management programs that synchronize ovulation can ovulate a smaller than normal fol... more Reproductive management programs that synchronize ovulation can ovulate a smaller than normal follicle, potentially resulting in inadequate progesterone (P4) concentrations after artificial insemination (AI). Ovulation of the dominant follicle of the first follicular wave with human chorionic gonadotropin (hCG) treatment can produce an accessory corpus luteum and increase circulating P4 concentrations. This manuscript reports the results of 2 separate analyses that evaluated the effect of hCG treatment post-AI on fertility in lactating dairy cows. The first study used meta-analysis to combine the results from 10 different published studies that used hCG treatment on d 4 to 9 post-AI in lactating dairy cows. Overall, pregnancies per artificial insemination (P/AI) were increased 3.0% by hCG treatment post-AI [34% (752/2,213) vs. 37% (808/2,184); Control vs. hCG-treated, respectively]. The second study was a field research trial in which lactating Holstein cows (n=2,979) from 6 commerc...

Produção e metabolismo da progesterona e seu papel antes, durante e depois da inseminação artific... more Produção e metabolismo da progesterona e seu papel antes, durante e depois da inseminação artificial influenciando a fertilidade de vacas leiteiras de alta produção

Reproduction, Fertility and Development, 2007

A recently suggested alternative to improve post-thaw ovine semen quality is the addition of semi... more A recently suggested alternative to improve post-thaw ovine semen quality is the addition of seminal plasma (SP). This is thought to be capable of improving sperm resistance to thermal shock, reverting cryo-capacitation and helping sperm survival in the female tract. The aim of this study was to evaluate the effect of thawed ram semen incubation with seminal plasma for 15 or 30 min as assessed by the fluorescent probes, Hoechst 33342 (40 µg mL−1), propidium iodide (0.5 mg mL−1), JC-1 (76.5 µM in DMSO), and FITC-PSA (100 µg mL−1 in Dulbecco's PBS (DPBS)), for cellular viability, plasmatic damage, mitochondrial activity, and acrosomal damage, respectively. Five ejaculates were collected from 4 different animals via artificial vagina and were pooled to eliminate individual differences. After thawing, semen was divided into 2 groups, one diluted with seminal plasma (1 : 1, 30% in DPBS) and the other in DPBS (1 : 1). After 15 and 30 min, fluorescent probes were added to 25 µL of each...

Journal of Dairy Science, 2014

The objective of this trial was to evaluate the effects of feed restriction (FR) on serum glucose... more The objective of this trial was to evaluate the effects of feed restriction (FR) on serum glucose, nonesterified fatty acids, progesterone (P4), insulin, and milk production in dairy cows. Eight multiparous Holstein cows, 114 ± 14 d pregnant and 685 ± 39 kg of body weight, were randomly assigned to a replicated 4 × 4 Latin square design with 14-d periods. During the first 8 d of each period, cows in all treatments were fed for ad libitum feed intake. Beginning on d 9 of each period, cows received 1 of 4 treatments: ad libitum (AL), 25% feed restriction (25FR), 50% feed restriction (50FR), and 50% of TMR replaced with wheat straw (50ST). Daily feed allowance was divided into 3 equal portions allocated every 8 h with jugular blood samples collected immediately before each feeding through d 14. In addition, on d 12 of each period, blood samples were collected before and at 60, 120, 180, 240, 300, 360, 420, and 480 min after morning feeding. The conventional total mixed ration and total mixed ration with straw averaged 15.1 and 10.8%, 32.1 and 50.5%, and 26.8 and 17.0% for concentrations of crude protein, neutral detergent fiber, and starch, respectively. Cows that were feed and energy restricted had reduced dry matter intake, net energy for lactation intake, circulating glucose concentrations, and milk production, but greater body weight and body condition score losses than AL cows. Circulating concentrations of insulin were lower for cows fed 50FR (8.27 μIU/mL) and 50ST (6.24 μIU/mL) compared with cows fed AL (16.65 μIU/mL) and 25FR (11.16 μIU/mL). Furthermore, the greatest plasma nonesterified fatty acids concentration was observed for 50ST (647.7 μEq/L), followed by 50FR (357.5 μEq/L), 25FR (225.3 μEq/L), and AL (156.3 μEq/L). In addition, serum P4 concentration was lower for cows fed AL than cows fed 50ST and 25FR. Thus, FR reduced circulating glucose and insulin but increased P4 concentration, changes that may be positive in reproductive management programs.

Proceedings of the Eighth International Symposium on Reproduction in Domestic Ruminants

Zygote, 2009

SummaryThe aim of this study was to assess the effect of exogenous DNA and incubation time on the... more SummaryThe aim of this study was to assess the effect of exogenous DNA and incubation time on the viability of bovine sperm. Sperm were incubated at a concentration of 5 × 106/ml with or without plasmid pEYFP–NUC. Fluorescent probes, propidium iodide/Hoechst 33342, FITC–PSA and JC-1, were used to assess plasma membrane integrity (PMI), acrosome membrane integrity (AMI) and mitochondrial membrane potential (MMP) respectively at 0, 1, 2, 3 and 4 h of incubation. Exogenous DNA addition did not affect sperm viability; however, incubation time was related to sperm deterioration. Simultaneous assessment of PMI, AMI and MMP showed a reduction in the number of sperm with higher viability (integrity of plasma and acrosome membranes and high mitochondrial membrane potential) from 58.7% at 0 h to 7.5% after 4 h of incubation. Lower viability sperm (damaged plasma and acrosome membranes and low mitochondrial membrane potential) increased from 4.6% at 0 h to 25.9% after 4 h of incubation. When P...

Zygote, 2011

SummaryThis study evaluated the effects of reversible meiotic inhibition and different culture me... more SummaryThis study evaluated the effects of reversible meiotic inhibition and different culture media (PZM3 or NCSU23) on production of porcine embryos by either in vitro fertilization (IVF) or parthenogenetic activation (PA). Oocytes from abattoir-derived ovaries were allocated into two groups for maturation: CHX (5 μg/ml cycloheximide for 10 h) or Control (no CHX). The percentage of metaphase II (MII) oocytes was determined at 36, 40 or 44 h of in vitro maturation. For IVF and PA, denuded oocytes were fertilized with purified sperm for 6 h or activated by electric stimuli. Zygotes were then subdivided into two culture groups: NCSU23 or PZM3. No effect of treatment with CHX and culture media was observed on cleavage (D3) and blastocyst (D7) rates in IVF and PA groups. There are no differences of quality or development rates between IVF-derived embryos cultured in NCSU23 or PZM3. However, we observed high quality PA embryos in PZM3 compared with NCSU23. Maturation arrest with CHX dec...

Theriogenology, 2013

Ovsynch-type synchronization of ovulation protocols have suboptimal synchronization rates due to ... more Ovsynch-type synchronization of ovulation protocols have suboptimal synchronization rates due to reduced ovulation to the first GnRH treatment and inadequate luteolysis to the prostaglandin F 2a (PGF 2a) treatment before timed artificial insemination (TAI). Our objective was to determine whether increasing the dose of the first GnRH or the PGF 2a treatment during the Breeding-Ovsynch portion of Double-Ovsynch could improve the rates of ovulation and luteolysis and therefore increase pregnancies per artificial insemination (P/AI). In experiment 1, cows were randomly assigned to a two-by-two factorial design to receive either a low (L) or high (H) doses of GnRH (Gonadorelin; 100 vs. 200 mg) and a PGF 2a analogue (cloprostenol; 500 vs. 750 mg) resulting in the following treatments: LL (n ¼ 263), HL (n ¼ 277), LH (n ¼ 270), and HH (n ¼ 274). Transrectal ultrasonography and serum progesterone (P4) were used to assess ovulation to GnRH1, GnRH2, and luteal regression after PGF 2a during Breeding-Ovsynch in a subgroup of cows (n ¼ 651 at each evaluation). Pregnancy status was assessed 29, 39, and 74 days after TAI. In experiment 2, cows were randomly assigned to LL (n ¼ 220) or HH (n ¼ 226) treatment as described for experiment 1. For experiment 1, ovulation to GnRH1 was greater (P ¼ 0.01) for cows receiving H versus L GnRH (66.6% [217/326] vs. 57.5% [187/325]) treatment, but only for cows with elevated P4 at GnRH1. Cows that ovulated to GnRH1 had increased (P < 0.001) fertility compared with cows that did not ovulate (52.2% vs. 38.5%); however, no effect of higher dose of GnRH on fertility was detected. The greater PGF 2a dose increased luteal regression primarily in multiparous cows (P ¼ 0.03) and tended to increase fertility (P ¼ 0.05) only at the pregnancy diagnosis 39 days after TAI. Overall, P/AI was 47.0% at 29 days and 39.7% at 74 days after TAI; P/AI did not differ (P ¼ 0.10) among treatments at 74 days (LL, 34.6%; HL, 40.8%; LH, 42.2%; HH, 40.9%) and was greater (P < 0.001) for primiparous cows than for multiparous cows (46.1% vs. 33.8%). For experiment 2, P/AI did not differ (P ¼ 0.21) between H versus L treatments (44.2% [100/226] vs. 40.5% [89/220]). Thus, despite an increase in ovulatory response to GnRH1 and luteal regression to PGF 2a , there were only marginal effects of increasing dose of GnRH or PGF 2a on fertility to TAI after Double-Ovsynch. Published by Elsevier Inc.

Theriogenology, 2014

The early corpus luteum (CL) (before Day 6) does not regress after a single PGF 2a treatment. We ... more The early corpus luteum (CL) (before Day 6) does not regress after a single PGF 2a treatment. We hypothesized that increasing PGF 2a dose or number of treatments would allow regression of the early CL (Day 5). Nonlactating Holstein cows (N ¼ 22) were synchronized using the Ovsynch protocol. On Day 5 (Day 0 ¼ second GnRH treatment), cows were assigned to: (1) control (N ¼ 5): no further treatment; (2) 1PGF (N ¼ 6): one dose of 25 mg PGF 2a ; (3) 2PGF (N ¼ 5): two doses of 25 mg PGF 2a (50 mg) given 8 hours apart (second PGF 2a on Day 5 at the same time as the other PGF 2a treatments); (4) DPGF (N ¼ 6): double dose of 25 mg PGF 2a (50 mg) given on Day 5. Blood samples were collected to monitor progesterone (P4) profiles in two periods. In the first period (0 to 24 hours), there were effects of treatment (P ¼ 0.01), time (P < 0.01), and an interaction of treatment and time (P ¼ 0.02). Group 1PGF versus control was different only at 12 hours (P ¼ 0.02). Cows treated with DPGF were different than control at 4 hours (P ¼ 0.04), 12 hours (P < 0.01), and 24 hours (P < 0.01). Only cows treated with 2PGF had lower P4 than control during the entire period and low P4 (0.37 AE 0.17 ng/mL) at 24 hours, usually indicative of luteolysis. In the second period (Day 5 to 15 of the cycle), there were effects of treatment (P < 0.01), time (P < 0.01), and interaction of treatment and time (P ¼ 0.002). Group 1PGF was not different than control from Day 5 to 13 and P4 was greater than control on Day 14 (P ¼ 0.01) and 15 (P < 0.01). Circulating P4 in DPGF cows was lower than control from Day 7 (P ¼ 0.05) through 12 (P < 0.01). Likewise, there were differences between control and 2PGF from Day 7 to 13, but not on Day 14 and 15. On Day 15, all PGF 2a-treated groups had circulating P4 consistent with an active CL. Ultrasound evaluation confirmed that no CL from any group completely regressed during the experiment and no new ovulations occurred to account for functional CL later in cycle. In summary, a double dose of PGF 2a (twice on Day 5 or 8 hours apart) can dramatically decrease P4, consistent with classical definitions of luteolysis; however, these CL recover and become fully functional. Thus, the Day 5 CL of mature Holstein cows do not regress even to two doses of PGF 2a .

Theriogenology, 2003

A new device was developed to hold linear transducers for transvaginal follicle aspiration. Ef®ca... more A new device was developed to hold linear transducers for transvaginal follicle aspiration. Ef®cacy of follicle aspiration was compared using a linear 6 MHz and a convex 5 MHz transducer. Fifty-®ve cows were submitted to follicle aspiration at random days of the estrous cycle. Aspirations were conducted with linear (n 28) and convex (n 38) transducers with 18 G needles at a negative pressure corresponding to 13 ml H 2 O/min. A greater number of follicles were aspirated using convex than to linear probe (12.4 versus 7.8, respectively, P < 0:05). Mean number of oocytes and recovery rates were similar for convex (5.4 and 48.6%) and linear (4.6 and 59.3%) transducers. Limited space between the linear transducer and needle guide restricted access to some portions of the ovary, reducing the number of follicles aspirated using a linear transducer. The newly developed adaptor allowed greater stability, holding the ovaries ®rmly against the linear transducer. This diminished mobility permitted a similar number of oocytes to be recovered with both transducers. In conclusion, this new adaptor provided a low cost alternative for routine follicle aspiration and oocyte recovery in cattle.

Reproduction in Domestic Animals, 2009

This study investigated the effect of porcine follicular fluid (PFF) and dibutyryl cyclic adenosi... more This study investigated the effect of porcine follicular fluid (PFF) and dibutyryl cyclic adenosine monophosphate (dbcAMP) during in vitro maturation (IVM) of porcine oocytes on meiotic maturation, fertilization and embryo development, and compared the effect of supplementing the embryo culture media with PFF or foetal bovine serum (FBS) on embryo development. Oocytes from pre-pubertal gilts were IVM for 44 h, and parthenogenetically activated or in vitro-fertilized. Embryos were cultured in porcine zygote medium (PZM3) for 7 days. Cleavage and blastocyst rates were evaluated at 48 h and 7 days of culture. The supplementation of the IVM medium with 25% PFF and 1 mm dbcAMP for the first 22 h resulted in more (p < 0.05) embryos developing to the blastocyst stage as compared with the inclusion of dbcAMP alone. The dbcAMP + PFF combination increased (p < 0.05) the average number of nuclei per blastocyst as compared with either of these components alone or in its absence. A synergistic effect of dbcAMP + PFF during IVM was also reflected in the capacity of oocytes to regulate sperm penetration and prevent polyspermy, as twice as many oocytes from the control group were penetrated by more than one sperm as compared with those matured in the presence of both dbcAMP and PFF. The supplementation of PZM3 with 10% FBS from days 5 to 7 of culture significantly improved the total cell quantity in embryos derived either from control or dbcAMP + PFF matured oocytes. There was no effect on the total cell quantity when FBS was replaced by the same concentration of PFF. These studies showed that dbcAMP, PFF and FBS can improve both the quantity (57.3% vs 41.5%) and quality (74.8 vs 33.3 nuclei) of porcine blastocysts derived from oocytes recovered of pre-pubertal gilts.