67 In vivo versus in vitro embryo production after superstimulation of donors in the camel (Camelus dromedarius)

Some elite female dromedary camels cannot produce offspring due to anatomical or pathological conditions of the reproductive tract. An in vitro embryo production system could be useful in harvesting the germplasm from such females. The present study was conducted to compare the number of embryos produced from superstimulated dromedary females either in vitro by somatic cell nuclear transfer (SCNT) after aspiration of the follicles by an ultrasound-guided transvaginal ovum pick-up or in vivo after their mating with fertile bulls. All donor animals in this study were subjected to serial ultrasonography and were induced to ovulate, once a dominant follicle was spotted, by administration of 20 μg of the GnRH analogue buserelin (Receptal; HoechstAnimal Health). Four days after ovulation, they were treated with a combination of 2000 IU equine chorionic gonadotrophin, given as a single IM injection on Day 1 of the treatment protocol, and 400 mg of FSH injected twice daily with declining doses over 4 days, also beginning on Day 1. After the end of treatment, ovaries of the donor camels were scanned, and thereafter at intervals of 1 or 2 days until most follicles had grown to between 1.3 and 1.8 cm in diameter. The number of follicles were recorded in all donors. In group 1 (n = 36), an injection of 20 μg of buserelin was given 26 h before the cumulus-oocyte complexes (COCs) were aspirated from the follicles using a 17 G, 55-cm single-lumen needle through a needle guide attached to the vaginal probe. All mature oocytes obtained were used to reconstruct the embryos by SCNT using skin fibroblast cells from six elite camels as donor nuclei (Wani et al. 2010 Biol. Reprod. 82, 373-379). Reconstructs were cultured in 500 µL of TCM-199 based embryo culture medium until Day 7. The total number of transferrable hatching/hatched blastocysts were recorded on Day 7. In group 2 (n = 12), the donors were mated with a fertile bull, and embryos were flushed out on Day 7 after mating. The data collected on the number of follicles and transferrable embryos obtained was analysed by ANOVA, and data are presented as mean ± s.e.m. per donor animal. As shown in Table 1, there was no difference (P > 0.05) in the number of follicles produced or transferrable embryos produced in these groups. This study demonstrates the use of ultrasound-guided transvaginal ovum pick-up in valuable donors that cannot produce embryos in vivo due to some anatomical or pathological condition of the fallopian tubes or uterus for in vitro embryo production. This method of embryo production could be used to salvage germplasm from such females, and the number of transferrable embryos produced in vitro could be on par with those produced in vivo. The use of semen collected from elite males for either intracytoplasmic sperm injection (ICSI) or IVF for fertilisation of the collected oocytes needs to be studied in future experiments.

Table 1.  Follicles and and transferrable embryos following in vitro or in vivo embryo production