We report the cryopreservation of oocytes from Ban miniature pigs which are endemic in Vietnam. Immature cumulus‐oocyte complexes were collected from antral follicles of 7–8 mo old female cyclic Ban pigs and vitrified in micro‐drops. Oocyte morphology, lipid content, post‐warming survival, nuclear maturation, and embryo development were compared to those of oocytes from commercially slaughtered Landrace × Large white hybrid pigs. The size of oocytes in the two breeds was similar. However, significantly lower amounts of intracellular lipid were detected in Ban oocytes. There was no difference (p > 0.05) between Ban and Landrace × Large white oocytes in percentages of post‐warming survival (93.1 ± 3.4% vs. 70.7 ± 16.7%, respectively) and nuclear maturation after in vitro maturation (80.4 ± 5.1% vs. 90.0 ± 1.3% respectively). Similarly, cleavage (30.8 ± 7.8% vs. 10.3 ± 6.1%, respectively) and blastocyst development rates (9.4 ± 5.0% vs. 0.79 ± 0.79, respectively) were not different (p > 0.05) between vitrified Ban and Landrace × Large white oocytes after in vitro fertilization and embryo culture. In conclusion, high survival and maturation rates were achieved after vitrification of immature Ban oocytes and their cryo‐tolerance was similar to that of Landrace × Large white oocytes, despite the difference in lipid content. We succeeded to generate reasonable rates of blastocysts from vitrified Ban oocytes by in vitro fertilization.

Our aim was to evaluate the quality of ejaculated and epididymal frozen-thawed pig sperm of endangered Vietnam native pig breeds. Ejaculated sperm was collected from live boars and epididymal sperm was collected from slaughtered boars of the MuongTe, Kieng Sat and Co BinhThuan breeds and frozen in 0.25 ml straws using a protocol established earlier for modern pig breeds. We evaluated the sperm quality after thawing in terms of motility and rates of viable and abnormal spermatozoa. Our results revealed that the sperm motility and rates of viable and abnormal frozen-thawed sperm were >30%, >44%, and <14%, respectively. The origin of sperm had an effect on the production of pig embryos in vitro. In the Co BinhThuan breed, ejaculated sperm generated higher cleavage, blastocyst and hatching rates than did the epididymal sperm (60.11% vs 56.02%, 17.23% vs 14.31%, 3.78% vs 2.34%, respectively, P < 0.05). Although no difference in cleavage rate, blastocyst formation rate and the average number of cells/blastocysts, the hatching blastocyst rate was different between the breeds (P > 0.05). In the Co BinhThuan breed, the rate of pregnancy of ejaculated groups was similar to that of the epididymal group. In conclusion, the ejaculated and epididymal sperm of native Vietnamese pigs were successfully frozen. We succeeded in creating embryos in vitro and pregnant pigs after artificial insemination from frozen-thawed semen in three native Vietnamese pig breeds for the first time. The use of the ejaculated sperm improved the production of native pig embryos in vitro efficiency.