In vitro production of functional haploid sperm cells from male germ cells of Saanen dairy goat.

The dairy goat is an important economic animal. Studies on in vitro differentiation of dairy goat spermatogonial stem cells (SSCs) could understand the molecular mechanisms for detecting mammalian sperm generation and innovative transgenetics. This study established an in vitro differentiation system for Saanen dairy goat SSCs. After 35 days incubation, single flagellum sperm-like cells with late round spermatid (Sa2) morphologically and the ability to express sperm-specific protein acrosin is detected. DNA ploid analysis showed that addition of testosterone to the culture system significantly improved the differentiation efficiency (P < 0.05) of haploid cells, and stimulated the post-meiotic gene (Tnp1, Tnp2 and Prm1) expression. A green fluorescent protein expressed in the morula was observed after transfection of the green fluorescent protein (GFP) vector with a round spermatid microinjection into the oocyte at metaphase II-stage. This study optimized activated method of the goat oocytes injected with round spermatids in vitro. This method increases the reconstructed embryonic development rate. These results suggest that testosterone boosts the efficiency of haploid cell differentiation in Saanen dairy goat testicular cells in the in vitro differentiation system. After optimization of activated and injection methods, fertility and embryonic were improved.