Cryopreservation of immature and mature camel (Camelus dromedarius) oocytes by open pulled straw vitrification | ||||
| Arab Journal of Biotechnology | ||||
| Volume 19, Issue 2, December 2016, Page 75-90 PDF (2.12 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/arjb.2016.428491 | ||||
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| Abstract | ||||
| The aim of the present investigation was to establish a reliable vitrification protocol for camel oocytes. A total of 540 cumulus oocyte complexes (COCs) were collected by manual slicing and divided into two groups. Three hundred oocytes were used to investigate the effect of the open pulled straw (OPS) vitrification procedure on the maturation rate of vitrified immature camel oocytes compared to control (non-vitrified). The rest (240 oocytes) were employed to evaluate the effect of vitrification on the morphological characteristics of immature and mature camel oocytes. COCs were treated with vitrification solution-1 (VS-1) 10% Dimethyl sulfoxide (DMSO) and 10% ethylene glycol (EG) for 30-45 sec and transferred to vitrification solution-2 (VS2) 20% DMSO, 2 0% EG and 0.5M sucrose . Oocytes were loaded into the OPS and then directly submerged into liquid nitrogen (LN2) for 1h. The average value of maturation rate between the vitrified immature camel oocytes and the non-vitrified group (control) revealed non-significant differences as indicated by expansion of oocytes (88% (132/150), and 85.3% (128/150), respectively). However, the average rate of extrusion of the first polar body was significantly reduced in the vitrified immature oocytes (20.3%) compared to control group (40.1%). In addition, the morphological abnormalities occurred at higher rate in vitrified immature (GV stage) oocytes than in vitrified mature oocytes 16/99 (13.6%) vs, 6/106 (6.4%), respectively. Consequently, the survival rate was significantly reduced in vitrified immature oocytes compared to vitrified mature oocytes (83.9% vs., 92.4%, respectively). In conclusion, the present study revealed that the camel oocytes could be successfully cryopreserved by OPS vitrification using EG and DMSO as cryoprotectant. Moreover, our results demonstrated that in camel mature oocytes are more resistant to cryoinjuries than immature oocytes and could produce a high percentage of normal oocytes that could be useful for future use in in vitro fertilization and camel improvement programs. | ||||
| Keywords | ||||
| Camel; Camelus dromedarius; Oocyte; Vitrification; Open pulled straw; Cryopreservation | ||||
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