203 Effect of aspiration pressure at the time of transvaginal ultrasound-guided follicle aspiration on cumulus-oocyte complex quality and embryo development in alpacas (Vicugna pacos)

In vitro embryo production (IVP) is a technique that can be used for improving genetics in alpacas; however, collection of good quality cumulus-oocyte complexes (COCs) from animals through the use of transvaginal ultrasound-guided follicle aspiration (OPU) is still in development. Among the main factors, aspiration pressure during the OPU may be affecting the quality of COCs at the time of collection. The aim of this work was to determine the effect of two aspiration pressures on the morphological quality of the COCs and their capacity to produce embryos in vitro in alpacas. For this purpose, eight alpacas were synchronised by follicular ablation and given a superstimulatory treatment of 500 IU of equine chorionic gonadotrophin (eCG) i.m. two days later. Four days after the eCG treatment, OPU was performed. On the day of the OPU, the alpacas were divided in two groups (n = 4 each) of different pressures during the OPU: (i) 30 mmHg and (ii) 100 mmHg. The OPU was performed using a 20 GA OPU-needle (WTA, Brazil) and a vacuum pump with tube warmers (Minitube, USA). In each group, collected COCs were classified according to the IETS manual and Grades 1, 2, and 3 were used for IVP. Collected COCs and presumptive zygotes were placed in maturation and culture media respectively. Maturation medium consisted of TCM-199, 10% fetal calf serum, 0.5 μg/mL FSH, 1 μg/mL oestradiol, 0.3 mMol sodium pyruvate, 50 μg/mL gentamicin, and 1% aa (essentials and no essentials). The semen was collected from two males, pooled, and used for the IVF in both groups. Medium SOFaa was used for in vitro culture. Seven days after IVF, embryos were evaluated. Chi-squared was used to analyse the data. Recovery (48% vs 46%) and cleavage rate (18% vs 11%) had no difference between 30 mmHg and 100 mmHg groups, respectively. Proportion of Grade 1 COCs was higher (P < 0.05) in the 30 mmHg group than in the 100 mmHg group (3/12 [25%] vs 1/11 [9%], respectively). Similarly, Grade 2 COCs were higher in the 30 mmHg (3/12 [25%] vs 0/11 [0%], respectively). Blastocyst rate was different between groups, it was higher in the 30 mmHg (2/11 [18%]) than in the 100 mmHg (0/9 [0%]). In conclusion, a pressure of 30 mmHg in the vacuum pump is recommended to perform OPU in superstimulated alpacas.

This study was supported by the Universidad Nacional Jorge Basadre Grohmann through funding from the Canon Minero of Tacna, Peru.