Effects of L-carnitine and different cryodevices on the vitrification and developmental competence of invitro fertilized buffalo oocytes

The cryopreservation of immature oocytes from buffalo provides a continuous non-seasonal source of female gametes. The current study compared different cryodevices and L-carnitine (LC) supplementation to the vitrifi-cation medium on the viability and developmental competenceofbuffalo oocytes. The immature oocytes were vitrified in TCM119 medium supplemented with 0.0, 0.3, 0.6 or 1.2 mg/ml of LC in either a straw (SD), open pulled-straw (OPS), or solid surface device (SSD). Vitrification in a straw resulted in higher rates of recovery (52.7 %)and viability (85.5 %) of oocytes in medium containing 0.6 mg/ml LC (P<0.05). Use of OPS resulted in greater recovery (50.2 %) and viability rates (79.7%)in medium containing 0.3 mg/mlLC (P<0.05). There were greater recovery (54.1%) and viability (83.3%)rates for medium containing 0.6 mg/ml LC and SSD (P<0.05).Abnormalities of the cytoplasm (all cryodevices) and zona pellucida (SD) were higher when medium contained 1.2 mg/ml LC (P<0.05) was used.Further-more, the maturation rates of oocytes were the greatest when using OPS and 0.3 mg LC (46.9 %, P<0.05). The rates of fertilization (60.5%), cleavage (27.9 %)and development of fertilized oocytes to blastocysts (16.3 %)were the greatest when using OPSand vitrification medium with 0.3 mg LC (P<0.05). In conclusion,the proper LC concentration differs at different cryodevices.The rates of recovery and viability were the greatest for medium with 0.6 mg/ml LC in either SD or SSD. However, when using OPS the best results were recorded when the medium contained 0.3 mg/ml LC.