Aspiração de oócitos e produção de embriões in vitro de vacas Jersey suplementadas com selênio

Abstract

The study was carried out to evaluate the influence of the additional selenium (Se) in oocytes donors' diet and in the in vitro embryos production. Ten Jersey cows were divided, randomly, in control groups (CG) and treatment (TR), receiving the same diet that only differed by the Se concentration in mineral salt. The CG received 3.2 mg of Se/cow/day and TR received 9.6 mg/cow/day. After 20 days from the treatment beginning, it was done the first follicular aspiration driven by ultrasound (US) that was discarded. Following this, it was done more five US with an average of 15 days. The oocytes where then classified in I, II and III quality, expanded, naked, atresic or degenerated. The in vitro embryos production was done in the BIOTEC - CESUMAR laboratory, according to standard routine and then evaluated in the seventh day after in vitro fertilization. During the experimental period (119 days) the animals had an average weight gain of 49.9 ± 13.47 kg/cow. The average of total oocytes (35.11 ± 2.65) and quality I oocytes (11.61 ± 1.58) were higher in the TR (P<0.05) than CG (23.10 ± 2.16 and 4.75 ± 0.97, respectively). The amount of naked oocytes was lower (3.24 ± 0.87) in the TR (P<0.05) while the atresic structure number (10.68 ± 1.62) and total unviable (11.23 ± 1.65) were higher (P<0.05). The total production of in vitro embryos and expanded blastocyst were higher (21.98 ± 2.37 and 10.95 ± 1.64, respectively) in TR (P<0.05), when compared with CG (13.12 ± 1.59 and 6.64 ± 1.15). The amount of initial blastocyst and blastocyst did not differ between the two groups (P>0.05).In accordance to the conditions in which the study was developed it is possible to conclude that the higher Se addition to diet resulted in higher oocytes production, higher quantity of degree I oocytes I and higher embryos production in the process of in vitro fertilization, recommending the use of 9.6 mg of Se/ day per cows donor of oocytes.