339 ULTRASOUND GUIDED OVUM PICK UP (OPU) IN PREPUBERTAL SWAMP BUFFALO USING THREE DIFFERENT VACUUM PRESSURES

Abstract

Our group successfully developed ovum pick-up in prepubertal swamp buffalo, however the quality of the oocytes that were collected was poor especially those without a cumulus mass (Techakumphu et al. 2003 Theriogenology 61, 1705–1711). The vacuum pressure used for oocyte collection was one of the factors influencing oocyte quality (Bols et al. 1997 Theriogenology 47, 1221–1236). The objective of this study was to compare the effect of three vacuum pressures on both the recovery rate and oocyte quality in prepubertal swamp buffaloes. Oocyte recovery and oocyte quality were using different groups of aspiration vacuum pressures. The maturation stages of the recovered oocytes were immediately assessed by fixation and rapid staining with basic carbol fuchsin. Twelve prepubertal calves, aged 1.5 yrs were a total of 180 mg FSH given, twice a day, in divided doses over 3 d (40/40, 30/30, 20/20). The animals were randomized into 3 groups, according to the different vacumm pressures, 100 (n = 8), 80 (n = 8) and 60 mmHg (n = 8). Two sets of treatments, carried out, with a 2 month interval between them. The oocyte recovery rates using 100 and 80 mmHg, were not different at 78.4% (29/37) and 83.6% (61/73). The 60 mmHg gave a lower rate, 65.7% (23/35) which was statistically different from the 80 mmHg group (P < 0.05). The oocytes recovered per donor showed no significant difference among the groups; 5.8 ± 4.9 for 100 mmHg, 7.6 ± 8.6 for 80 mmHg and 3.3 ± 2.1 for 60 mmHg respectively. The percentage of cumulus-oocyte complex (COC), single layered+partial cumulus oocytes (S + P) and expanded cumulus oocytes (EXP) showed no differences for any of the pressures, being 79.3, 65.5 and 82% of the total recovered. The experiment showed that follicles with a size of 2–6 mm were dominant after FSH treatment, being around 80% of the total number. Furthermore, the maturation stages of these oocytes were at prophase I and metaphase I. In conclusion, the vacuum pressure used for the oocyte retrieval technique influenced the recovery rate but not the oocyte quality. This study was supported by Rajadapisek Sompoj Fund, Chulalongkorn University year 2002. AP was PhD candidate under Royal Golden Jubilee, Thailand Research Fund.