Indução de estro e produção de embriões em ovinos

Abstract

Evaluated the effect of different doses of D-cloprostenol, synthetic analog of the Prostaglandin F2α (Croniben®-lab.Biogenesis) and the method of administration in 47 lambs, with age between eight to ten months, from three breeds; Santa Inês (n=16), Ille de France (n=15), and Texel (n=16). The experiment was carried out at the Campus of Arenito, Universidade Estadual de Maringá, Cidade Gaúcha, Paraná. Animals were maintained on pastures that contained Aruana grass (Panicum maximum vc. IZ-5) during the day; at nights they were housed in appropriate installations that had slotted floors. All lambs received diets with 60% the total digestible nutrients rations in which the crude protein content varied from 12% to 16%. The herd was randomly distributed in four experimental groups based on dosage and way of administration of PGF2α (Croniben®-lab.Biogenesis), in such manner that all experimental groups had four animals from each breed, except experiment DIM, which had three lambs Ille de France. All animals received on day zero (D0) a vaginal pessario that contained 60 mg of Medroxyprogesterone Acetate (MAP) (Estro Forte®, Estro Forte Reprodução Animal Ltda.) that was removed on the twelfth day (D12). When this was being removed, the lambs received the applications referent to each PGF2α experiment: SOM (2 ml saline solution, way intramuscular), DIM (150 μg of D-cloprostenol, way intramuscular), MEM (75 μg of D-cloprostenol, way intramuscular), and MEV (75 μg of D-cloprostenol, way vulvar mucosa). Estrus observations were done during five consecutive days, three times daily, morning, middle of the day and afternoon. Four vasectomized rams with libido previously evaluated were used. Twenty one lambs demonstrated estrus: five from the SOM group; three from the DIM group; six from the MEM group; and seven from the MEV group. Statistical differences were not observed between the variables evaluated, except from the genetic group, where lambs from the breeds Santa Inês and Ille de France were different (P < 0.05) from Texel lambs. In other study the number of corpus luteum (CL), embryonary structures, and the viability of embryos were verified in Santa Ines ewes that received sources of fatty acids Omega 3 or Omega 6. The experiment was carried out in the municipal district of Cidade Gaúcha, PR, from May to June, 2004, and repeated on September to October, 2005. 24 ewes were divided in three experimental groups: T1-Control; T2-LAC-100 (lab.Yakult); and T3-Linseed grains. All animals received isoenergetic rations with variable sources of fatty acids. Thirty days after administration of the controlled ration, each donor sheep received an ear implant of prostegerone (Crestar®-lab.Intervet), indicating D0 of the hormonal treatment. The superovulatory process started at D12 with the administration of 250 UI of Follicle Stimulating Hormone (FSH-Pluset®-lab.Serono) in decreasing doses. On D14 the prostegerone product was removed and 150 μg of D-Cloprostenol, synthetic analog of the Prostaglandin F2α (Croniben®-lab.Biogenesis) was aplicated; all donors showed estrus in the morning of D16 and were placed to ram 12 and 24 hours later, with three males of the same breed. On D23 surgical collection of embryos was carried out, and the number of corpus luteum present in each ovary was recorded. The uterine horns were flushed with 50 ml of modified Dulbecco solution (DMPBS), the effluent placed in Petry Dishes, and analyzed by stereoscope microscopy. The structures observed were collected and transferred to a second Petry Dish that contained maintenance solution, where the quality and development of the embryonary structures were classified. No effect (P >0.05) of the treatment on the number of corpus luteum or total number of estructures was observed, but had effect (P<0.05) in the viability of the embryos in the Lac-100 group (omega 6). The sources of omega 3 or omega 6 did not improve the superovulatory response, but source of omega 6 improved the viability of the embryos.