Produção de embriões em ovinos Morada Nova e Somalis Brasileira

A study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non-surgical uterine flushing

The present study compared the outcomes of in vivo embryo production in Morada Nova ewes subjected to either 9-day (G-9_SOV , n=21) or 12-day (G-12_SOV , n=21) progesterone (P₄ )-based estrus 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 estrus. Total antral follicle count doubled from the 1^st to the 6^th pFSH dose in both groups (P < 0.05). Estrus 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 estrus behavior in G-9_SOV and G-12_SOV , respectively. NSER was successfully completed in 86.2% of ewes that had CL (P > 0.05). The mean number of CL per ewe/successfully flushed donor ewe was greater (P < 0.05) in G-12_SOV (12.3 ± 1.7/12.1 ± 1.9) than in G-9_SOV (7.9 ± 1.4/8.2 ± 1.6). Mean numbers of retrieved blastocysts and viable embryos were greater (P > 0.05) in G-12_SOV (5.8 ± 1.9 and 3.7 ± 1.7) than G-9_SOV (3.5 ± 1.1 and 0.8 ± 0.3, respectively). The total follicle count (all follicles ≥ 2 mm in diameter) at the 6^th pFSH dose (at P₄ -device removal) was positively correlated (P < 0.05) with the number of CL (r = 0.95) and viable embryos (r = 0.91) in G-12_SOV . The ewes with ≥ 10 CL (48% of all flushed donors) yielded 80.5% of viable embryos. In summary: i. Morada Nova ewes from G-12_SOV group had better superovulatory responses compared with G-9_SOV group; ii. 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 iii. animals with ≥ 10 ovulations are main contributors to viable embryo production in Morada Nova ewes.

NonSurgical Embryo Recovery from Estrus-Synchronized or Superovulated Morada Nova Ewes: A Feasible Strategy for Sheep Embryo Banking

This study assessed the feasibility of in vivo embryo production and nonsurgical embryo recovery (NSER) in Morada Nova ewes (an endangered native Brazilian breed of sheep) subjected to different estrus synchronization and/or superovulation protocols. Ewes received intravaginal sponges soaked with 60 mg medroxyprogesterone acetate (MAP), which were kept in place for six (G6; n = 12), nine (G9; n = 12), or 12 (G12; n = 12) days. Half of the ewes in each group remained estrus synchronized only (_SYNCH) and the other half was superovulated (_SOV) with 133 mg porcine follicle-stimulating hormone (pFSH). There were no differences (p > 0.05) in antral follicle counts determined with ultrasonography 60 hours before MAP sponge removal (or at the time of the first pFSH dose) among G6 (6.4 ± 0.9), G9 (6.2 ± 0.7), and G12 (5.5 ± 0.6). Estrus responses and NSER success rates did not vary (p > 0.05) among the three progestin-treatment groups of ewes for either estrus-induced or superovulated animals. The onset of estrus occurred 10-12 hours later (p < 0.01) in G9_SYNCH ewes compared with G6_SYNCH and G12_SYNCH, and the duration of estrus was ∼19 hours greater (p < 0.01) in G9_SOV than in G6_SOV. The average duration of the NSER procedure was 32.6 ± 1.3 minutes. At least one structure was recovered in 85.7% of synchronized and in 87.5% of superovulated ewes. Viable embryo recovery rates were also similar (p > 0.05) for G6 (1.0 ± 0.3 and 2.5 ± 1.5), G9 (1.3 ± 0.5 and 4.8 ± 2.0), and G12 groups (1.0 ± 0.3 and 4.8 ± 2.3; estrus-synchronized and superovulated ewes, respectively). In conclusion, progestogen pretreatment of different durations and NSER can be employed in Morada Nova ewes, resulting in reasonable viable embryo recovery rates in both estrus-synchronized and superovulated animals. Therefore, both techniques are suitable for use in commercial settings as well as small ruminant conservation programs.

Relationship between superovulation and embryo production with ovarian follicular population before superovulatory treatment in Brazilian Bergamasca sheep

ABSTRACT The objective of this study was to quantify the superovulatory response and embryo production of Brazilian Bergamasca sheep and to evaluate the link to the follicular condition before superovulatory treatment, as a reference for selection of donors with potential for superovulation. Follicular population of twenty-three sheep was evaluated by ultrasound during metestrus phase of the estrous cycle and divided into groups of low, medium and high follicular population. Subsequently, they were synchronized, superovulated with 133mg of pFSH, mated and subjected to embryo collection. The superovulatory response (9.0±3.3 vs 10.7±6.2 vs 13.8±7.1) and embryo production (4.0±3.8 vs 2.6±2.0 vs 1,8±4.0) were similar between groups (P>0.05). There was a positive correlation between the number of follicles during the metestrus phase and the number of corpus luteum with premature regression (PLR) (0.52) and a negative correlation between the recovery rate and PLR (-0.44) (P<0.05). The sheep that presented PLR had more follicles during metestrus (16.9±7.8 vs 12.7±3.2) and lower embryo recovery rate (38.8±29.3 vs 72.2±29.9) than those with functional CLs (P<0.05). Follicular quantification during metestrus phases was unable to identify donors with high embryo production. Animals with PLR had a larger follicular population during metestrus and lower embryo recovery rate.