Effect of synthetic eCG like glycoprotein on follicular development and embryo recovery in llamas

Abstract

The aim of this study was to compare the efficacy of two doses (700 and 1000 IU) of the native eCG (N-eCG) and a synthetic eCG like glycoprotein (S-eCG) on ovarian superstimulation and embryo production in llamas. Females were examined daily by transrectal ultrasonography until a follicle ≥ 7 mm was observed and a GnRH analogue was injected (i.v.) (Day 0). On Day 3, transrectal ultrasonography was performed to confirm the absence of follicles > 5 mm and animals were randomly divided into four groups (n=10/group): N-eCG700, N-eCG1000, S-eCG700 and S-eCG1000 which received 700 or 1000 IU (i.m.) of N-eCG or S-eCG, accordingly. On Day 7, 112.5 μg of cloprostenol (i.m.) was injected in all llamas. On Day 10, the number of follicles ≥7 mm, mean diameter and their vascularization were determined by ultrasonography. Then, llamas were injected with a GnRH analogue and mated. Natural mating was repeated 24 h later. On Day 18, the number of corpora lutea (CL), their diameter and vascularization were assessed and embryo recovery was performed by uterine flushing. On Day 10, there were no significant differences in the number of follicles ≥ 7 mm, neither in their diameter or vascularization between groups. Similarly, no significant differences were observed in the number of CL on Day 18, neither in their diameter or vascularization between groups. In conclusion, the results of the present study indicate that S-eCG produced by recombinant technology has the same biological activity as N-eCG in llamas.