Oocyte cryopreservation is a strategic tool for assisted reproduction, but has limited use due to the complex cellular structure of oocytes, which leads to sub-optimal survival rates. In this study, we used the SPOM in vitro maturation system, which is based on supplementation of cAMP modulators in order to extend meiotic arrest and improve oocyte maturation. cAMP modulators (Forskolin and IBMX) were administered in a short term culture (STC) before or after vitrification, followed by an extended maturation with cilostamide. We hypothesized that a STC with cAMP modulators would improve immature oocyte health and enhance cryotolerance. We found vitrification caused oocyte damage in a great extent, impairing nuclear maturation rates in all vitrified groups (Percentage of matured oocytes: CONT FRESH 77.8 c ; CONT VIT 31.4 ab ; STC/VIT 39.5 b ; VIT/STC 18.6 a). Vitrification also promoted degradation of cytoskeletal actin filaments (Percentage of
Context In vivo embryo production, also called multiple ovulation and embryo transfer, can accelerate genetic gain, and thus improve animal production. However, there are issues limiting a wider use of this biotechnology in sheep livestock. Aims This study aimed to determine (1) whether a previous response to superovulation (SOV) can be used as a criterion to select ewes for in vivo embryo production, (2) whether the intensity of the SOV response (number of corpora lutea, CL) can affect the embryo recovery rate, and (3) whether the number of CL quantified by colour Doppler ultrasonography can be used to calculate the recovery rate. Methods Twenty-five Santa Inês ewes underwent SOV three times (SOV1, SOV2 and SOV3), with 200 mg FSH and natural mating. The number of CL after each SOV was determined by laparoscopy and by colour Doppler ultrasonography. Key results The number of CL significantly decreased (P < 0.05) after SOV1 (7.5 ± 4.8) to 3.0 ± 5.0 at SOV 2 and 2.2 ± 3.5 at SOV3. Strong correlations were observed between SOV2 and SOV3 in terms of numbers of CL (r = 0.86, r2 = 0.74; P < 0.0001) and viable embryos (r = 0.79, r2 = 0.63; P < 00001). However, no correlations were observed between SOV1 and SOV2 or between SOV1 and SOV3. Recovery rate did not differ with the intensity of the SOV response (≤6, 7–10, >10 CL) or between the methods used to quantify CL. Conclusions Ewes did not show the same pattern of response when submitted to successive FSH-based SOV. The intensity of the SOV response did not affect the recovery rate, and the number of CL estimated by colour Doppler ultrasonography can be used to calculate the recovery rate. Implications Selecting sheep embryo donors by a previous SOV response is not always feasible. The recovery rate is homogeneous and it is not affected by the intensity of the SOV response. A nonsurgical technique can be used to assess the recovery rate, improving animal welfare in MOET programs.
The present study aimed to evaluate the effect of the simulated physiological oocyte maturation (SPOM) system on F1 Gyr × Holstein oocytes and embryos by evaluating the meiotic arrest, embryo production rates, total number of cells and lipid score. Three experiments were conducted and the following three experimental groups were formed according to in vitro maturation (IVM) treatments: CONTROL 1 (TCM 199 medium without FBS), CONTROL 2 (commercial medium) and SPOM (TCM 199 medium with forskolin and 3-isobutyl-1-methylxanthine (IBMX) in pre-IVM and extended IVM with cilostamide). In the first experiment (ovum pick-up), a significant (P < 0.05) reduction in the percentage of matured oocytes in SPOM group was observed. In the second (slaughterhouse ovaries) and third (ovum pickup) experiments, the cleavage and blastocyst rates were reduced (P < 0.05) in the SPOM group. There was no significant (P > 0.05) difference in total number of cells among the groups. No difference (P > 0.05) was found on lipid score among the groups at Day 7 of development, in both Experiments 2 and 3. At Day 9 (Experiment 2), only the CONTROL 2 showed a significant increase (P > 0.05) compared with the other treatments. It was concluded that under our conditions, the SPOM system was efficient in prolonging meiotic arrest on Gyr × Holstein oocytes, offering the oocytes in vitro conditions more similar to those found in vivo; however, it adversely affected embryo production rates and promoted no beneficial effect on the total number of cells and the lipid score.
RESUMOO objetivo deste estudo foi avaliar o efeito da adição de probiótico com ou sem Ca e Zn na mistura mineral sobre a concentração sérica de Zn em ovinos. A adição de probióticos contendo Ca e Zn resultou na redução da concentração sérica de Zn em relação aos grupos Gc e GP, respectivamente. Não houve diferença significativa (p<0,05) entre os grupos e dias de observação, portanto a adição de elementos minerais aos probióticos torna-se prejudicial à saúde dos ovinos, podendo predispor os animais a apresentar deficiências subclínicas e/ou clínicas de um determinado mineral ao longo do tempo da utilização destes produtos.
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