129 Effect of equine chorionic gonadotrophin doses on number and size of ovarian follicles at the time of oocyte collection in llamas
U. H. Perez A , F. W. Gutierrez A , Y. M. Quispe A , J. H. Melgar B , N. Luque C , H. W. Deza D , J. M. Palomino E and M. G. Pérez AA Universidad Nacional del Altiplano de Puno, Puno, Perú
B Escuel de Post Grado, Universidad Nacional del Altiplano, Puno, Perú
C Centro Experimental Chuquibambilla, Universidad Nacional del Altiplano de Puno, Puno, Perú
D Universidad Peruana Cayetano Heredia, Lima, Perú
E Boviteq Inc., Saint Hyacinthe, Canada
Reproduction, Fertility and Development 34(2) 302-303 https://doi.org/10.1071/RDv34n2Ab129
Published: 7 December 2021
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of the IETS
In vitro embryo production (IVP) has been attempted in South American camelids mainly using oocyte recovered from abattoir ovaries. Few experiences of oocyte collection from superstimulated live animals have been reported. Early experiences of ovarian superstimulation in llamas and alpacas have shown that eCG induces multiple follicular development but with variable results. Thus, developing a well-established protocol of ovarian superstimulation is necessary in this species. The aim of this study was to evaluate the effect of three doses of equine chorionic gonadotrophin (eCG) on multiple follicular development and the size of the follicles at the time of oocyte collection. To this purpose, 18 adult llamas (4–7 years old), non-lactating, and with a BCS of 2.8 (range 0–5) were synchronised by follicular ablation and randomly allocated to three groups (n = 6 each) of superstimulation: (i) 500 IU, (ii) 750 IU, and (iii) 1000 IU. The eCG was given intramuscularly 2 days after ablation in all groups. Four days after eCG treatment, transrectal ultrasonography was done to record the number and size of ovarian follicles and transvaginal ultrasound-guided follicular aspiration (ovum pick-up, OPU) was performed to collect oocytes. Number and size of follicles were analysed by one-way ANOVA and the recovery rate by chi-squared and presented as mean ± s.e.m. or percentage. The average size (mm) of follicles on the day of OPU was greater (P ≤ 0.05) in the 1000 IU group (8.08 ± 0.08) compared to the other groups (6.13 ± 0.16 and 6.99 ± 0.18 in groups 500 IU and 750 IU respectively). Total number of aspirable follicles (≥3 mm) was not different between the 750 IU (7.75 ± 1.03) and 1000 IU (8.5 ± 0.65) groups, but was lower in the 500 IU group (6.2 ± 0.2). Conversely, the number of large follicles (≥7 mm) was greatest (P ≤ 0.05) in the 1000 IU group (7.4 ± 0.34) vs. the 500 IU (2.8 ± 0.51) and 750 IU (4.2 ± 0.47) groups. There was no difference in recovery rate among groups (42% (10/24), 50% (12/24), and 48% (14/24) for 500 IU, 750 IU, and 1000 IU, respectively). In conclusion, superstimulatory treatment with 1000 IU of eCG produced more larger follicles at OPU, and it may benefit future programs of ovarian superstimulation, OPU, and IVP in llamas.
This research was funded by Fondo Nacional de Desarrollo Científico, Tecnológico y de Innovación Tecnológica (FONDECYT)-CONCYTEC del proyecto ‘Monitoreo y control de la actividad folicular y su aplicación en la producción de embriones in vitro en camélidos sudamericanos en el Altiplano Peruano’ (Convenio 000399-2019-FONDECYT-DE).
