228 Effect of seminal plasma on the interval to application of equine chorionic gonadotrophin for the recovery of cumulus-oocyte complexes in alpacas (Vicugna pacos)

Abstract

Alpacas as other camelids are induced ovulators and require an external stimulus-mounting by the male-for ovulation. NGF-β, protein present in the seminal plasma (SP) is reported as being responsible for stimulating ovulation. However, limited information exists on the effect of ovulation inducers in the new follicular wave emergence with application on protocols of superstimulation. The aim of the study was to determine the effect of two ovulation induced techniques and two different times on the interval to application of equine chorionic gonadotrophin (eCG) for the ovarian superstimulation for the recovery of COCs by ovum pick- up (OPU). Alpacas were evaluated by transrectal ultrasonography with an Aloka SSD 500 ultrasound and transducer (7.5MHz) to determine the presence of a dominant follicle=7mm. A 2×2 experimental design was used with adult female alpacas, 6 to 8 years old, which were assigned to one of the treatments when a dominant follicle=7mm was present. Alpacas were assigned randomly 1 of 2 groups (Day 0) in which follicular ovulation was induced by seminal plasma 1mL IM (SP, n=13; group 1) with application of 650IU of eCG at 36h (n=6) or 48h (n=7) post-application of SP, or by GnRH with 0.008mg of Buserelin IM (GnRH, n=10; group 2) with application of 650IU eCG at 36h (n=5) or 48h (n=5) post-application of GnRH. On Day 7, COCs were counted and the OPU procedure was performed in every group. Data were analysed using ANOVA. Results are presented in Table 1. In conclusion, both inducers of ovulation and both times of application of eCG were effective for producing follicles of 7mm and COCs acceptable for recovery in Alpacas. Table 1.Number of follicles=7mm (top) and number of COCs recovered (mean±s.e.m.) Outcome and group 36 h 48 h Total Follicles GnRH 6.8±1.93 13.4±4.34 10.10±2.50a SP 5.5±2.23 5.29±1.15 5.38±1.25b Total 6.09±1.44 8.67±2.18 7.43±1.33 COCs GnRH 5±0.97 3±1.26 4.33±0.74a SP 1±0.41 0.33±0.22 0.67±0.25b Total 3.29±0.67x 1.4±0.6y 2.5±0.53 a,bValues within columns with different letters differ significantly (P=0.05). x,yValues within columns with different letters differ significantly (P=0.05). This research funded by CIENCIACTIVA-CONCYTEC as part of the project title “Role of seminal plasma in reproductive physiology and application of biotechnologies in camelids” (149-2017).