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Publications (3)5.29 Total impact

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    ABSTRACT: In vitro-produced (IVP) bovine embryos are more sensitive to cryopreservation than their in vivo counterparts due to their higher lipid concentrations, whereas Bos indicus IVP embryos are even more sensitive than Bos taurus IVP embryos. To examine the effects of a lipolytic agent, before vitrification of Bos indicus IVP embryos, on embryo survival, viability, and pregnancy rates, two experiments were conducted. In experiment 1, Bos indicus (Nelore) embryos were produced from abattoir-derived ovaries and allocated into two groups. In the treatment group, 10 μM of forskolin was added to the in vitro culture medium on Day 5 and incubated for 48 hours. On Day 7 of culture, IVP-expanded blastocysts from both the control (n = 101) and treatment (n = 112) groups were vitrified with ethylene glycol and DMSO via the Cryotop procedure. Although there was no significant difference between the rates of blastocoel reexpansion and hatching of the embryos exposed to forskolin (87.5% and 70.5%, respectively) compared with the control embryos (79.2% and 63.3%, respectively), the numerically superior rates of the embryos exposed to forskolin led to another experiment. In experiment 2, blastocysts produced from the ovum pick up were exposed or not exposed to the lipolytic agent and vitrified as in experiment 1. Embryos treated with forskolin had higher pregnancy rates than the control group (48.8% vs. 18.5%). In view of these results, 1908 Bos indicus embryos were produced from ovum pick up, exposed to the lipolytic agent, and blastocysts were transferred to recipients, and the pregnancy rates of the embryos of various breeds were compared. The mean pregnancy rate obtained was 43.2%. All data were analyzed by chi-square or by binary logistic regression (P ≤ 0.05). In conclusion, treatment with forskolin before vitrification improved cryotolerance of Bos indicus IVP embryos, resulting in good post-transfer pregnancy rates.
    Theriogenology 06/2013; · 2.08 Impact Factor
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    ABSTRACT: To evaluate the feasibility of long distance transport of ovine oocytes and in vitro produced embryos. Santa Ines pluriparous sheep (n = 5) were synchronized with intravaginal devices containing 0.3 mg progesterone (CIDR®, Pfizer, Netherlands) for 10 days. Thirty-six hours prior to progesterone device removal and follicular aspiration, 0.04 mg d-cloprostenol sodium (Ciosin®, Coopers, Brasil), 200 IU FSH (Folltropin®, Bioniche, Canada) and 300 IU eCG (Novormon®, Syntex, Argentina) were administered intramuscularly. Oocyte retrieval was performed via mid-ventral laparotomy, under general anesthesia. The oocytes were evaluated and classified under a stereomicroscope and placed in cryovials with TCM 199, aerated with 5% CO2, covered with mineral oil, sealed, wrapped with parafilm and stored in a transport incubator at 38.5 °C. Oocytes were then transported via the road for 14 h to the laboratory, where the oocytes then completed more than 10 h of IVM. In vitro fertilization (IVF) was performed with frozen sperm from a single ram. On Day 3 the embryos were placed in cryovials containing SOFovine (In Vitro Brasil, Sao Paulo, Brazil), aerated with 5% CO2, covered with mineral oil, sealed, wrapped with parafilm and placed into the same portable incubator. The embryos were returned to the farm under the same transport conditions (km and h). Upon arrival at the farm, all embryos were evaluated and transferred into recipient ewes 4 days after the initial oocyte retrieval. Embryos were transferred in sets of 3 to 4, into the apex of the uterine horn, ipsilateral to the corpus luteum, by means of mid-ventral laparotomy, under general anesthesia. Pregnancy was diagnosed using transrectal ultrasonography 30 days after embryo transfer. On average 9.8 ± 5.7 oocytes (49 oocytes/5 donors) were obtained per donor, and 25 grade I morulae were transferred into 7 recipients. One pregnancy (14.3%) was confirmed resulting in a healthy lamb. These results indicate the feasibility of in vitro embryo production in sheep after maturation and embryonic development following transport over long distances.
    Small Ruminant Research 01/2012; 105(s 1–3):286–289. · 1.12 Impact Factor
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    ABSTRACT: The number of oocytes recovered from Bos taurus indicus females subjected to ovum pick-up averaged two to four times greater compared to Bos taurus taurus females. The objective of the present study was to test the hypothesis that this difference in oocyte yield was due to more preantral follicles in the ovaries of Bos indicus females. Ovaries (n = 64) from Nelore (Bos indicus) fetuses (n = 10), heifers (n = 12), and cows (n = 10), and Aberdeen Angus (Bos taurus) fetuses (n = 10), heifers (n = 12), and cows (n = 10) were cut longitudinally into halves, fixed, and processed for histological evaluation. The number of preantral follicles was estimated by counting them in each histological section, using the oocyte nucleus as a marker and employing a correction factor. The average number of preantral follicles in the ovaries of Bos indicus vs Bos taurus was (mean ± SD) 143,929 ± 64,028 vs 285,155 ± 325,195 for fetuses, 76,851 ± 78,605 vs 109,673 ± 86,078 for heifers, and 39,438 ± 31,017 vs 89,577 ± 86,315 for cows (P > 0.05). The number of preantral follicles varied greatly among individual animals within the same category, as well as between breeds. In conclusion, we inferred that the higher oocyte yield from Bos indicus females was not due to a greater ovarian reserve of preantral follicles. Therefore, mechanisms controlling follicle development after the preantral stage likely accounted for differences between Bos indicus and Bos taurus females in number of oocytes retrieved at ovum pick-up.
    Theriogenology 06/2011; 76(6):1051-7. · 2.08 Impact Factor