n-3 Polyunsaturated fatty acids (n-3 PUFA) are important for human health. Alternative resources of n-3 PUAFs created by transgenic domestic animals would be an economic approach. In this study, we generated a mfat-1 transgenic cattle expressed a Caenorhabditis elegans gene, mfat-1, encoding an n-3 fatty acid desaturase. Fatty acids analysis of tissue and milk showed that all of the examined n-3 PUAFs were greatly increased and simultaneously the n-6 PUAFs decreased in the transgenic cow. A significantly reduction of n-6/n-3 ratios (P<0.05) in both tissue and milk were observed.

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It is known that oocytes can be activated without male contribution in vitro and develop to blastocysts which are used to isolate parthenogenetic embryonic stem cells. Unfortunately, differentiation capacity of the parthenogenetic embryonic stem cells was rather lower than fertilized embryos derived ES cells, which might be the result of the absence of male genome. It had been found that some maternally expressed genes were repressed and some paternally expressed genes were expressed in the non-growing oocytes. Therefore, maternal genome from non-growing oocytes can partially act as "sperm genome". In the present study, parthenogenetic blastocysts containing genome from non-growing and fully grown oocytes (named as NF-pBlastocysts) were produced by germinal vesicle transfer, and three newly established parthenogenetic embryonic stem (named as NF-pES) cell lines were derived from the resulting parthenogenetic blastocysts. All three NF-pES cell lines were positive for ES cell markers, such as alkaline phosphatase (AKP), stage-specific embryonic antigen 1 (SSEA-1) and octamer-binding transcription factor (Oct-4). They have a normal chromosome karyotype (40) and can be maintained in an undifferentiated state for extended periods of time. When NF-pES cells were injected into severe combined immunodeficient mice, teratomas with all three embryonic germ layers were obtained. The in vitro differentiation potential of NF-pES cells was analyzed by embryonic bodies (EB) formation. The expression of germ layer markers, such as nestin (ectoderm), desmin (mesoderm), and alpha-fetoprotein (endoderm) demonstrated that the NF-pES cells can differentiate into all three germ layers.