Eduardo Kenji Nunes Arashiro

Luteal dynamics in goats: morphological and endocrine features

Objetivou-se neste estudo estabelecer as caracteristicas morfologicas e endocrinas da dinâmica luteal em cabras. Foram utilizadas femeas da raca Toggenburg que manifestaram estro natural em um intervalo de 48 horas. Apos o estro, foram realizadas avaliacoes ultrassonograficas diarias dos ovarios durante 21 dias, utilizando-se um aparelho portatil (5 MHz). Amostras de sangue foram coletadas para dosagem de progesterona (P4) no plasma. Os corpos luteos foram detectados pela primeira vez no D5 e aumentaram progressivamente de tamanho ate o D9 (1,26 ± 0,08 cm2), nao havendo variacao nos dias subsequentes. Nas femeas com uma ovulacao, a primeira visualizacao do corpo luteo foi mais precoce que naquelas com ovulacao multipla (4,54 ± 0,18 vs 5,74 ± 0,25 dias). No momento da primeira visualizacao, a area luteal foi menor nos animais com uma ovulacao. A concentracao plasmatica de P4 aumentou progressivamente ate o D9 e nao apresentou aumento significativo ate o momento da luteolise, caracterizada por uma acentuada queda da concentracao de P4, atingindo valores inferiores a 1 ng/mL em um intervalo de 24 horas. A area luteal diminuiu de forma lenta e gradual. Foi observada uma correlacao positiva significativa entre a area e a concentracao de P4 durante a lutegeonese e a luteolise (r = 0,63 e r = 0,50; respectivamente). No dia em que o corpo luteo atinge sua area maxima (D9), as femeas com mais de um corpo luteo, com maior area de tecido luteal, nao apresentaram concentracao de P4 superior a daquelas com uma ovulacao (5,92 ± 0,59 vs 7,04 ± 0,79 ng/mL). Esses resultados indicam que a dinâmica luteal em caprinos da raca Toggenburg segue padroes semelhantes aos observados em outras racas e em outras especies e que o crescimento de tecido luteal refletiu positivamente na funcionalidade do corpo luteo.

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

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.

Dose and administration protocol for FSH used for ovarian stimulation affect gene expression in sheep cumulus–oocyte complexes

The present study evaluated the effect of four ovarian stimulation protocols on the follicular population and molecular status of cumulus-oocyte complexes (COCs). Twelve Santa Inês ewes (in a cross-over design) received 80 or 120mg FSH alone in a multiple-dose (MD80 and MD120) regimen or in combination with 300IU equine chorionic gonadotrophin (eCG) in a one-shot (OS80 and OS120) protocol. The follicular population, COC recovery rate, mean COCs per ewe and the rate of brilliant Cresyl blue-positive (BCB+) COCs were similar among treatments (P>0.05). The expression of markers of oocyte competence (ZAR1, zygote arrest 1; MATER, maternal antigen that embryo requires; GDF9, growth differentiation factor 9; BMP15, bone morphogenetic protein 15; Bcl-2, B-cell lymphoma 2; BAX, Bcl-2 associated X protein) and the steroidogenic pathway (ERα, oestrogen receptor α; LHr, LH receptor; FSHr, FSH receptor; STAR, steroidogenic acute regulatory protein) was affected by stimulation. Specifically, the expression of markers of the steroidogenic pathway was reduced with increasing FSH dose in the OS protocol. FSH at a dose of 80mg reduced the expression of FSHr and ERα in the OS versus MD protocol. Conversely, in MD protocol, only LHr was affected by increasing FSH dose. In conclusion, 80mg FSH in the MD or OS protocol was sufficient to promote the development of multiple follicles and obtain fully grown (BCB+) oocytes. The MD protocol may be more appropriate for the production of better-quality oocytes.