Publications (2)1.39 Total impact
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ABSTRACT: The aim of the present study was to evaluate the effects of different medium replacement intervals on the viability, antral cavity formation, growth and in vitro maturation (IVM) of oocytes from caprine and ovine pre-antral follicles. Pre-antral ovarian follicles (≥ 150 μm) were isolated from the ovarian cortex of goats and sheep and were individually cultured for 24 days using two different medium replacement intervals [2 days (T(1) ) or 6 days (T(2) )]. Follicle development was evaluated on the basis of antral cavity formation, increases in follicular diameter and the presence of healthy cumulus oocyte complexes and fully grown oocytes. For caprine species, results showed a higher percentage (p<0.05) of viable follicles in T(1) than T(2) from day 6 until the end of the culture. In addition, when comparing both treatments after the same culture duration, the rate of antrum formation was significantly higher in T(1) than in T(2) from day 12 onwards. Yet, in ovines, when both treatments were compared on day 24 of the culture, there were more viable follicles in T(2) than in T(1) (p<0.05). In the caprine species, percentages of fully grown oocytes (≥ 110 μm) acceptable for IVM after 24 days of culture were significantly higher in normal follicles cultured in T(1) (30.0%) than in T(2) (6.7%; p<0.05). On the other hand, in ovines, at the end of the culture, the percentage of oocytes destined for IVM was higher in T(2) than in T(1) (23.5% vs 2.9%; p<0.05). In conclusion, under the same conditions, the frequency of medium replacement significantly affected the in vitro development of caprine and ovine pre-antral follicles. To improve the efficiency of the culture system, the medium must be replaced every 2 and 6 days for goat and sheep pre-antral follicles, respectively.Reproduction in Domestic Animals 02/2011; 46(1):134-40. · 1.39 Impact Factor
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ABSTRACT: The aim of this study was to verify the influence of three different protocols for medium refreshing on the in vitro culture of isolated caprine preantral follicles. Independently of the protocol, preantral follicles were individually cultured for 18 days, the initial volume of medium was 25μl, and the interval of medium refreshing was every two days. The protocols tested were: T1 (Control) – refreshing of 15μl (removal of 15μl of culture medium followed by the addition of the same volume of fresh medium), maintaining a final volume of 25μl, T2 – only the addition of 5μl of fresh medium every two days (the medium volume increases 5μl for each change up to a final volume of 65μl at day 18), and T3 – initial removal of 15μl of medium in the first change, with addition of 20μl of fresh medium (net increase of 5μl in the final volume at each change). In the subsequent changes for T3, the amount of medium added in the previous change was removed, followed by the addition of the same volume plus 5μl fresh medium (as occurred for T2 the final volume at day 18 is also 65μl). Analyses of survival, diameter and antrum formation, as well as the rate of daily follicular growth were performed every 6 days. At the end of the culture period, normal oocytes ≥110μm were destined for in vitro maturation (IVM). The results showed that only T2 (addition without removal of medium) maintained follicular survival until the end of the culture period. In day 18, both follicular diameter and the rate of daily growth was similar in T2 and T3 (Removal+Addition of medium), which were both higher than in T1 (Partial change). Moreover, T2 obtained a greater percentage of oocytes >110μm destined for IVM and was the only treatment that achieved an oocyte in the telophase-I stage. In conclusion, periodic addition of medium is recommended because it is more practical, maintains survival and promotes the development of caprine preantral follicles in vitro.Small Ruminant Research - SMALL RUMINANT RES. 01/2011; 95(2):139-143.