Publications by authors named "Eduardo Kenji Nunes Arashiro"

8 Publications

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Hormonal protocols for early resynchronization of ovulation in ewes: The use of progestagens, eCG, and inclusion of early pregnancy diagnosis with color Doppler ultrasound.

Theriogenology 2019 Jul 30;133:113-118. Epub 2019 Apr 30.

Faculdade de Veterinária, Universidade Federal Fluminense, Niterói, Rio de Janeiro, 24230-340, Brazil. Electronic address:

This study aimed to evaluate 1) the effect of inserting an intravaginal sponge containing medroxyprogesterone during the late luteal phase on the corpus luteum (CL) function and endogenous production of P4; 2) the effectiveness of two different equine chorionic gonadotrophin (eCG) doses on synchronization of ovulations for a resynchronization treatment; and 3) the inclusion of an early pregnancy diagnosis in an early resynchronization protocol for ovulation in ewes. For all studies, the synchronization protocol was based on a short-term protocol of six days of progestogen treatment plus one dose of prostaglandin F2alpha, one dose of eCG, and gonadorelin acetate after sponge withdrawal. For the first study, the ewes were mated with fertile rams; a second sponge was inserted in half of these ewes 12 days later, and blood samples were collected daily for six days, until sponge withdrawal. For the second study, the ewes were not mated, and received a second sponge during the same period, after which they were divided into three groups according to eCG dose (0, 200, or 300 IU). In the third study, all ewes were artificially inseminated and received the second sponge during the same period. At sponge withdrawal, pregnancy was diagnosed by color Doppler ultrasonography (DUS) of the CL, and only non-pregnant ewes were re-inseminated two days later. In the first study, serum progesterone values were similar regardless of whether an intravaginal sponge had been inserted. In the second study, the ovulation time was more concentrated in those ewes which received 200 IU of eCG. In the third study, there was no difference between the experimental groups (with or without a previous pregnancy diagnosis) in pregnancy rate at the first insemination, accumulated pregnancy rate, and pregnancy loss. The insertion of an intravaginal sponge impregnated with medroxyprogesterone acetate did not affect the endogenous production of P4. The application of 200 IU of eCG provided the best result with regard to the synchronization of ovulations in the resynchronization treatment. Also, the inclusion of an early pregnancy diagnosis with DUS is useful and improves the general results of resynchronization programs, shortening the total working period.
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http://dx.doi.org/10.1016/j.theriogenology.2019.04.033DOI Listing
July 2019

Accuracy of assessment of luteal morphology and luteal blood flow for prediction of early pregnancy in goats.

Theriogenology 2018 Nov 14;121:104-111. Epub 2018 Aug 14.

Faculdade de Veterinária, Universidade Federal Fluminense, Niterói, Rio de Janeiro, 24230-340, Brazil. Electronic address:

This study aims to determine the best post-breeding time for an early pregnancy diagnosis in dairy goats, when using luteal morphology and vascularization assessment by B-Mode and color Doppler ultrasonography (US) in association or not with the anechoic uterine content. A total of 131 Saanen goats (2.0 ± 0.5 years old) were used in the two studies. In the first study, pregnancy prediction was daily performed from Day 15-23 post-breeding in 51 does. This was based on a subjective assessment of luteal morphology (B-Mode US), luteal blood flow (color Doppler US), and the presence of anechoic uterine content (B-Mode US). In the second study, pregnancy predictions were performed in 71 does on the best post-breeding day, as determined in the first study (Day 21 using luteal blood-flow assessment and Day 23 using luteal morphological assessment and overall analysis). In both studies, pregnancy diagnosis was confirmed on Day 30 (gold standard method by B-Mode transrectal ultrasonography). The B-Mode and color Doppler US performance in reaching an early pregnancy diagnosis was evaluated by calculating sensitivity (Sens), specificity (Spec), negative and positive predictive values (NPV and PPV), accuracy (Acc), the Kappa index (κ), and the Younden index (J). In Study 1, the pregnancy prediction accuracy progressively increased from Day 17-23 using B-Mode US (D17: 50.98%; D18: 52.94%; D19: 62.75%; D20: 74.51%; D21: 86.27%; D22: 90.20%; D23: 96.08%), and from Day 17-21 using color Doppler US (D17: 49.02%; D18: 54.90%; D19: 70.59%; D20: 86.27%; D21: 96.08%). In the second study, color Doppler, B-Mode, and overall assessments at Day 21 and Day 23, respectively, presented a similar pattern of sensitivity, specificity, and accuracy as was found in the first study. Therefore, both color Doppler and B-Mode assessments can be judged as effective tools for reaching a pregnancy diagnosis in goats as early as on Day 21 and Day 23, respectively, post-breeding.
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http://dx.doi.org/10.1016/j.theriogenology.2018.08.007DOI Listing
November 2018

Effects of hCG administration on accessory corpus luteum formation and progesterone production in estrous-induced nulliparous Santa Inês ewes.

Anim Reprod 2018 Aug 16;15(2):135-139. Epub 2018 Aug 16.

Faculty of Veterinary Medicine, Fluminense Federal University, Niterói, RJ, Brazil.

The effect of hCG administration on accessory corpus luteum (ACL) formation, CL area, and plasma progesterone (P4) concentration (ng/mL) seven days after breeding was studied in nulliparous Santa Inês sheep. Intravaginal 60 mg MAP sponges were inserted into ewes for six days and 300 IU eCG i.m. and 30 µg d-cloprostenol latero-vulvar were administered 24 h before sponge removal. Ewes were naturally bred and, seven days after first mating (Day 0; D0), were treated with either 250 IU hCG (hCG group; n = 7) or 1 mL saline solution (control group; n = 7). Blood was collected to determine plasma P4 concentrations and sonograms were performed on Days 7, 10, 13, 16, 19, and 22. Number of CL on D7 was similar (P > 0.05) between hCG (1.3 ± 0.5) and control (1.3 ± 0.5) groups; however, on D13, it was greater (P < 0.05) in the hCG group (2.3 ± 0.5) than in the control group (1.3 ± 0.5). A greater (P < 0.05) luteal tissue area was detected in hCG-treated ewes (n = 4) on Days 16 to 22 than in the animals in the control group (n = 7). Plasma P4 concentration on D13 to D22 was higher (P < 0.05) in hCG-treated animals than in control ewes. Administration of hCG seven days after estrus onset efficiently induced accessory CL formation in ewes, increasing luteal tissue area and plasma P4 concentration.
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http://dx.doi.org/10.21451/1984-3143-AR2017-957DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8186880PMC
August 2018

Cervical transposition test using Hegar dilator at oestrus as a tool to select ewes for transcervical embryo collection.

Reprod Domest Anim 2019 Jan 5;54(1):126-128. Epub 2018 Sep 5.

Faculdade de Veterinária, Universidade Federal Fluminense (UFF), Niterói, Brazil.

This study evaluated the cervical transposition method as a tool to select ewes for embryo collection by transcervical route. Adult Santa Inês ewes (n = 50) received Day 0 protocol for superovulation treatments. The cervix transposition test was performed both at oestrus and at the embryo collection time. The latter was preceded by hormonal cervical dilation. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 85.7%, 66.6%, 85.7%, 66.6% and 80.0%, respectively. The kappa index yielded a moderate score (κ = 0.52). In conclusion, the high sensitivity and accuracy indicate that the cervical transposition test is a screening option to select ewes for embryo collection by transcervical route.
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http://dx.doi.org/10.1111/rda.13306DOI Listing
January 2019

Anti-Müllerian hormone and antral follicle count are more effective for selecting ewes with good potential for in vivo embryo production than the presence of FecG mutation or eCG pre-selection tests.

Theriogenology 2018 Jun 23;113:146-152. Epub 2018 Feb 23.

Faculdade de Veterinária, Universidade Federal Fluminense, Rua Vital Brazil Filho, 64, CEP 24230-340, Niterói, RJ, Brazil.

This study aims to compare four different methods for selecting high responding sheep donors for in vivo embryo production. These methods include a pre-selection eCG test (eCG), antral follicle count (AFC), plasma anti-Müllerian hormone measurement (AMH) and genotyping for the presence of the FecG mutation (a polymorphism in the GDF9 gene associated with increased ovulation rate). Santa Ines ewe lambs (n = 25) underwent superovulation (SOV) with 800 IU equine chorionic gonadotropin (eCG) and the corpus luteum (CL) count was recorded by laparoscopy after eight days. At the D0, blood samples for AMH and genotyping analysis were collected. Twenty-one days after the end of the eCG test, the same animals underwent SOV with 200 mg of FSH, administered in six decreasing doses, and then naturally mated. Immediately before the beginning of the FSH protocol (D0), and at the moment of the first FSH dose (D9), the AFC was assessed. Plasma AMH was again determined at the D9. After each screening process, animals were classified as having a high (HR), or low (LR), potential of response (using specific thresholds for each method). Then, the ewes' response to SOV and embryo yield for each screening method, classified as HR or LR, were compared. Animals classified as HR by AFC (HR) and by AMH concentration (HR) at the D9, produced more viable embryos than those classified as LR and LR (HR 6.2 ± 3.2 vs LR 2.8 ± 3.0 and HR 6.6 ± 3.6 vs LR 3.0 ± 2.9). Pre-selection tests with eCG and different FecG genotypes, either heterozygous (+/E) or wild type (+/+), were unable to discriminate HR or LR animals. A tendency (P = 0.06) to have lower plasma AMH was observed in heterozygous FecG (+/E) ewes. In conclusion, both AFC and plasma AMH can be used to select donor ewes with a higher potential of response for in vivo embryo production.
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http://dx.doi.org/10.1016/j.theriogenology.2018.02.018DOI Listing
June 2018

Early pregnancy diagnosis in ewes by subjective assessment of luteal vascularisation using colour Doppler ultrasonography.

Theriogenology 2018 Jan 22;106:247-252. Epub 2017 Oct 22.

Faculdade de Veterinária, Universidade Federal Fluminense, Niterói, Rio de Janeiro, 24230-340, Brazil. Electronic address:

This study was designed to evaluate early pregnancy diagnosis using colour Doppler ultrasonography (US) for luteal vascularisation assessment. In Study 1, 28 ewes were artificially inseminated (Day 0), and luteal vascularisation was assessed from Day 12 to Day 19 by two evaluators using colour Doppler US, categorising the corpus luteum (CL) on a subjective scale ranging from 1 to 4. Females bearing a CL with score 2 or greater were presumably considered pregnant. Pregnancy was confirmed on Day 30 by B-Mode US. In Study 2, a predictive pregnancy diagnosis was performed on Day 17 in 197 ewes based on the criteria described in Study 1. Pregnancy was confirmed by B-mode US on Day 45. Agreement between evaluators was verified by an intraclass correlation coefficient (ICC) and Kappa index (κ). Performance of colour Doppler US for early pregnancy diagnosis was evaluated calculating sensitivity (Sens), specificity (Spec), negative predictive values (NPV), positive predictive values (PPV) and accuracy (Ac). In Study 1, luteal vascularisation assessment was unable to predict non-pregnant animals between 12 and 14 days after insemination, as all animals still had vascularised CL, and thus were considered pregnant. The colour Doppler US performance improved progressively until Day 17, when it reached maximum values (Sens = 100%, Spec = 76%, PPV = 73%, NPV = 100% and Ac = 86%). The subjective scale for luteal irrigation assessment showed medium to good agreement among evaluators on Day 12 and Day 13 (ICC = 0.66 and 0.68, respectively), and excellent agreement from Day 14 to Day 19 (ICC = 0.90, 0.80, 0.80, 0.84, 0.95 and 0.93, respectively). Agreement was almost perfect for score 1 CLs (κ = 0.87), and moderate for scores 2, 3 and 4 CLs (κ = 0.54, 0.48 and 0.41, respectively). In Study 2, performance of colour Doppler US as a tool to predict pregnancy status in ewes on Day 17 post-insemination was as follows: Sens = 93.5%, Spec = 80.8%, PPV = 85.6%, NPV = 91.1% and Ac = 87.8%. Subjective luteal vascularisation assessment using colour Doppler US to distinguish between pregnant and non-pregnant animals was considered a reliable tool which was highly efficient beginning 17 days after breeding.
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http://dx.doi.org/10.1016/j.theriogenology.2017.10.029DOI Listing
January 2018

Effect of different hormonal combinations on follicular wave emergence and superovulatory response in sheep.

Theriogenology 2017 Nov 26;103:24-29. Epub 2017 Jul 26.

Faculdade de Veterinária, Universidade Federal Fluminense, Niterói, RJ, Brazil. Electronic address:

The aim of the present study was to compare hormonal treatments to induce and synchronize follicular wave emergence to improve the results of superovulatory (SOV) treatments in ewes. In Experiment 1 (n = 66), ewes were treated with a progesterone intravaginal implant plus a PGF analogue (group G), or with the same treatment plus estradiol benzoate (G), a GnRH agonist (G), or both, estradiol benzoate and a GnRH agonist (G) in a 2 × 2 factorial arrangement. Follicular wave emergence was determined by ultrasound. Follicular wave did not emerge during the studied period in 10 females (one from G, six from G and three from G). Follicular emergence was less synchronized (P = 0.007) when estradiol was administered (G: 103.6 ± 22.0 h), without any interaction with GnRH treatment (G: 80.1 ± 21.4 h, G: 52.5 ± 8.7 h, G: 56.6 ± 10.4 h). Estradiol administration delayed the moment of follicular emergence (P = 0.007) and the follicular wave emergence moment in which follicular dominance was achieved (P = 0.009), without interactions between estradiol and GnRH in the moment of follicular wave emergence or dominance. In Experiment 2 (n = 22), two SOV protocols were compared: the best treatment of Experiment 1 (G) was used to synchronize follicular wave emergence, initiating the SOV treatment 2.5 days later; in the control treatment, SOV treatment started 80 h after a short-term protocol to synchronize ovulation (G). The number of corpora lutea (CL) and the evaluation of the collected embryos were performed six days after estrus. Blood samples were collected daily for plasma progesterone determination. Although the number of CL was similar in G (7.1 ± 1.0) and G (6.9 ± 5.1), the number of structures and viable embryos recovered were greater in G (P < 0.05). The occurrence of luteal premature regression was significantly greater in G (60%) than in G (8.3%). The use of GnRH agonist alone did not improve synchronization of follicular wave emergence. When EB was used (alone or associated) follicular wave emergence was less synchronized. The SOV protocol proposed had a similar ovarian response; however, it resulted in less transferable embryos.
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http://dx.doi.org/10.1016/j.theriogenology.2017.07.036DOI Listing
November 2017

Characterization of blood flow and the effects of exogenous estradiol benzoate on residual follicles formed after ultrasound-guided transvaginal follicle aspiration in cattle.

J Anim Sci Biotechnol 2016 6;7:59. Epub 2016 Oct 6.

Embrapa Recursos Geneticos e Biotecnologia, PqEB Av. W5 N, Brasilia, DF 70770-917 Brazil.

Background: Removal of the follicular content by ultrasound-guided transvaginal follicle aspiration (TVFA) may fail to induce immediate atresia and loss of function, resulting in the occurrence of residual follicles (RF). The aims of this study were to characterize the blood flow in RF and to determine the effects of the treatment with estradiol benzoate on RF fate. Lactating, cyclic Holstein-Gir crossbred cows were used. In Experiment 1, follicular wave emergence (D0) was synchronized in cows ( = 10) and follicular growth was then monitored by transrectal ultrasonography from D0 to D8, followed by TVFA of the largest follicle present on the ovaries 24 h later. Color Doppler ultrasound imaging was used to examine blood flow on the follicular wall, which was recorded immediately before and every 12 h after TVFA, up to 72 h. In experiment 2, cows ( = 22) were randomly allocated to receive either 2 mL of saline i.m. (Control group,  = 11) or 2 mL estradiol benzoate i.m. (EB group,  = 11) immediately after TVFA. Ovaries were scanned every 12 h to confirm the presence and to measure the diameter of RF. The contents of the RF, if present, were collected 72 h after the first TVFA, using the same aspiration procedures. Follicular fluid from original follicles and RF were stored at -20 °C until hormonal assays.

Results: In Experiment 1, there was no reduction ( 0.05) of blood flow in the remaining follicle walls after TVFA and maximum blood flow values were observed at 49.5 ± 19.7 h post-TVFA. In Experiment 2, formation of RF after TVFA was proportionally similar between Controls (5/9) and EB (5/10) cows. Also, RF diameter did not differ between groups ( 0.05). Nonetheless, the content of RF from cows in the EB group had lower ( = 0.0004) estradiol (E2) concentration and lower ( = 0.0005) E2:P4 ratio compared with Controls.

Conclusions: In conclusion, 1) the persistence of vascularization in the remaining follicle wall may contribute to the formation of RF after follicle aspiration, and 2) the treatment with estradiol benzoate does not prevent formation of RF, but does reduce their estradiol production.
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http://dx.doi.org/10.1186/s40104-016-0117-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5053028PMC
October 2016
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