The first dromedary ( Camelus dromedarius) offspring obtained from in vitro matured, in vitro fertilized and in vitro cultured abattoir-derived oocytes

Abstract

Dromedary offspring have never been produced fully in vitro. We have previously demonstrated that embryos obtained by culture in semi-defined medium (mKSOMaa) have better in vitro development ability than those cultured with oviductal epithelial cells. The aim of the present experiment was to study the pregnancy rate after embryo transfer of in vitro-produced (IVP) dromedary embryos cultured in semi-defined modified medium (mKSOMaa). IVM/IVF procedures were conducted on six hundred and sixty four (664) cumulus oocytes complexes (COCs) aspirated from ovaries collected at a local slaughterhouse and cultured in vitro (38.5 °C; 5% CO 2, and maximum humidity >95%). Maturation was completed by incubation in TCM-199 medium supplemented with 10% heat-treated Fetal Calf Serum (FCS), 10 ng/mL EGF, 1 μg/mL FSH, 1 μg/mL E2 and 500 μM cysteamine for 30 h. In vitro fertilization was performed using fresh semen (0.5 × 10 6 spermatozoa/mL in modified TALP-solution). Fertilized oocytes were cultured in mKSOMaa, under 38.5 °C, 5% CO 2 and 90% N 2 with maximum humidity (>95%). All IVC steps were done in seven replicates. The cleavage rate (two cells to blastocyst stage) was 64% (425/664) and the percentage of oocytes reaching the blastocyst stage was 23% (155/664). The hatching rate of blastocyst obtained after culture was 46% (71/155). Good quality hatched blastocysts ( n = 66) were transferred individually to synchronized recipients. Pregnancy rates, determined by ultrasonography at 15, 60 and 90 days after embryo transfer (ET), were 38%, 32% and 27%, respectively. Out of 18 pregnant females 5 aborted between the fifth and seventh month of pregnancy and 13 females (20%) remained pregnant. After 385 days of pregnancy, the first healthy and normal male-dromedary offspring produced fully in vitro was born at a birth weight of 38 kg. More dromedary calves ( n = 4) were born later on. The remaining pregnant females ( n = 8) are due to calf within the next months. In conclusion, this is the first reported offspring in camelids obtained by transfer of embryos produced by IVM, IVF and IVC using abattoir-derived oocytes, fresh semen and culture in a semi-defined medium.