Effect of 1000 IU of synthetic eCG like glycoprotein on follicular development and embryo recovery in llamas

Abstract

The aim of this study was to evaluate the effect of asynthetic eCG like glycoprotein on follicular development and embryo production, as an alternative to native eCGin llamas. METHODS: Twenty non-gestating and non-lactating llamas wereexamined daily by transrectal ultrasonography (tUS) to assesovarian status (MyLab One Vet, ESAOTE) until a growingfollicle with a diameter ≥7 mm, considered ovulatory in thisspecies, was observed. At that moment, females received8 μg of a GnRH analog (IV) (buserelin acetate, Gonaxal®Biogénesis Bagó, Argentina) (Day 0). On Day 3, tUS wasperformed to confirm the absence of follicles > 5 mm andthen animals were divided in two groups: eCG-N (n= 10)received 1000 IU of native eCG (IM) (Novormon®, Syntex,Argentina), and eCG-R (n= 10) received 1000 IU of asynthetic eCG like glycoprotein (IM) (Syntex, Argentina).On Day 7, all llamas were injected with 112.5 μg ofcloprostenol (IM) (Enzaprost®, Biogénesis Bagó). On Day10, the number of ovulatory follicles were determined bytUS and then llamas were mated with a male with provenfertility. Afterwards, females were injected with 8 μg ofbuserelin acetate (IV) and 24 h later, natural mating was repeated with another male, in order to minimize the male effect. On Day 18, the number of corpus luteum (CL) that developed after mating were assessed by tUS and then embryo recovery was performed by uterine flushing. The number of follicles that developed after treatment andthe number of collected embryos between groups werecompared by Mann-Whitney test. The number of CL that developed after mating between groups were comparedby unpaired t-test. Values are expressed as mean ± SEM.RESULTS: No significant differences were observed between groupsin the number of ovulatory follicles observed on Day 10(10.5±2.9 vs. 8.4±1.3 in the eCG-N and eCG-R, respectively), nor in the number of CL that developed after mating(9.2±3 vs. 8.2±1.2 in the eCG-N and eCG-R, respectively).The number of collected embryos did not show significant differences between groups (2.6±1.1 and 3.3±1.1 in theeCG-N and eCG-R, respectively). CONCLUSIONS: The synthetic eCG like glycoprotein shows a similar effect with regards to follicular development and embryo collection than the native eCG.