Study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non-surgical uterine flushing
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2022-04-01
Autores
Oliveira, Maria Emilia Franco [UNESP]
Arrais, Aline Matos
de Mello, Marco Roberto Bourg
Vergani, Gabriel Brun [UNESP]
Figueira, Lucas Machado
Esteves, Sérgio Novita
Pereira, Verônica Schinaider do Amaral
Garcia, Alexandre Rossetto
Bartlewski, Pawel Mieczyslaw
da Fonseca, Jeferson Ferreira
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Resumo
The present study compared the outcomes of in vivo embryo production in Morada Nova ewes subjected to either 9-day (G-9SOV, n = 21) or 12-day (G-12SOV, n = 21) progesterone (P4)-based estruses synchronization protocol coupled with superovulatory treatment with decreasing doses of porcine follicle-stimulating hormone (133 mg of pFSH given over 3 days). Non-surgical embryo recovery (NSER) was performed 6–7 days after the onset of oestrus. Total antral follicle count doubled from the first to the sixth pFSH dose in both groups (p <.05). Oestrus responses did not vary between the two groups of animals (95.2%). Corpora lutea (CL) were detected in 85.0% and 60.0% of ewes that previously manifested oestrus behaviour in G-9SOV and G-12SOV respectively. NSER was successfully completed in 86.2% of ewes that had CL (p >.05). The mean number of CL per ewe/successfully flushed donor ewe was greater (p <.05) in G-12SOV (12.3 ± 1.7/12.1 ± 1.9) than in G-9SOV (7.9 ± 1.4/8.2 ± 1.6). Mean numbers of retrieved blastocysts and viable embryos were greater (p >.05) in G-12SOV (5.8 ± 1.9 and 3.7 ± 1.7) than G-9SOV (3.5 ± 1.1 and 0.8 ± 0.3 respectively). The total follicle count (all follicles ≥2 mm in diameter) at the sixth pFSH dose (at P4-device removal) was positively correlated (p <.05) with the number of CL (r =.95) and viable embryos (r =.91) in G-12SOV. The ewes with ≥10 Cl (48% of all flushed donors) yielded 80.5% of viable embryos. In summary: (a) Morada Nova ewes from G-12SOV group had better superovulatory responses compared with G-9SOV group; (b) total follicle count at the last pFSH dose was a good predictor of superovulatory responses only in the ewes primed with P4 for 12 days; and (c) animals with ≥10 ovulations are main contributors to viable embryo production in Morada Nova ewes.
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in vivo embryo production, naturalized sheep breed, non-surgical embryo recovery, NSER, superovulation
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Reproduction in Domestic Animals, v. 57, n. 4, p. 393-401, 2022.