FROZEN STORAGE OF PORCINE ZYGOTE MEDIUM 3 FOR IN VITRO CULTURE OF CLONED PORCINE EMBRYOS

Zubing Cao1a, Ronghua Wu1a, Dandan Song1, Fei Han1, Xia Li1, Pengfei Zhang1, Xiaorong Zhang1,2 and Yunhai Zhang1,2*

1College of Animal Science and Technology, Anhui Agricultural University, No. 130 of Changjiang West Road, Hefei 230036, P. R. China
2Anhui Provincial Laboratory of Local Animal Genetic Resources Conservation and Biobreeding , No. 130 of Changjiang West Road, Hefei 230036, P. R. China
aEqual contributing authors
*Correspondence Author E-mail: yunhaizhang@ahau.edu.cn

ABSTRACT

The present study was designed to examine whether the frozen storage of porcine zygote medium (PZM) with 3 mg/ml of BSA was feasible for culturing porcine embryos. In experiment 1, the effect of PZM3 that was frozen and stored within one week on the in vitro developmental competence of porcine parthenotes was evaluated. PZM3 that was stored at 4°C served as control. The results show that the cleavage (83.9±1.2% vs. 84.5±1.8%, P>0.05) and blastocyst (65.2±2.1% vs. 63.1±3.8%, P>0.05) rates are similar between frozen-warmed PZM3 and the control. In addition, the total cell numbers per blastocyst (50±7 cells vs. 47±5 cells, P>0.05) were similar between the groups. In experiment 2, we tested whether PZM3 in frozen storage for 5 months was able to support the in vitro development of parthenotes similar to that supported by freshly made PZM3. The results show that no statistical differences were observed although the cleavage (97.8±2.7% vs. 90.7 ±3.1%, P>0.05) and blastocyst (75.4 ±1.6% vs. 65.1±2.3,P>0.05) rates in the control group were slightly higher than that in the test group. Also, we found no significant differences in the total cell numbers per blastocyst (48±7 cells vs. 46±6 cells, P>0.05) between the groups. In experiment 3, the effect of PZM3 frozen storage on the pre-implantation development of porcine-cloned embryos was investigated. Our results indicate no significant differences in the rates of cleavage (71.5±5.1% vs. 78.1±1.9%, P>0.05) and blastocyst formation (34.6±7.6% vs. 38.2±3.5%, P>0.05) as well as the total cell numbers per blastocyst (40±11 vs. 48±9, P>0.05) between the test and control groups. Taken together, our results imply that the frozen storage of PZM3 is feasible and of practical value for culturing parthenote and cloned porcine embryos.
Key words: Frozen storage, in vitro culture, porcine embryo, pre-implantation development, PZM3.