Effect of Concentration of Calf Serum onin vitroDevelopment ofin vitroProduced Bovine Embryos

Tsuzuki, Y., Ashizawa, K. and Fujihara, N. 1998. Effect of concentration of calf serum on in vitro development of in vitro produced bovine embryos. J. Appl. Anim. Res., 14: 137–142. Effect of concentration of calf serum (CS) in culture medium for in vitro development of bovine embryos produced by in vitro fertilization was evaluated In experiment 1, embryos were cultured in medium supplemented with 1, 15 and 20% (V/V) CS for 10 days after fertilization. The cleavage of embryos from 2 to 16 cells stage, determined on the 3rd day after insemination and development rate of embryos upto the morula and blastocyst (MB) stage by the 10th day after insemination were not significantly different among the groups (P>0.05). However, the percentage of MB stage embryos per cleaved embryo in 15% CS group was significantly higher (P<0.05) compared to 1% CS group. In experiment 2, embryos were cultured in medium supplemented with 1% CS for 3 days. Thereafter, one group of embryos was cultured in medium supplemented with 15% CS for a further 7 days, and the other embryos continued to be cultured in medium with 1% CS. Developmental rate up to MB stage and percentage of MB stage embryos by cleaved embryos in 15% CS was significantly higher (P<0.05) compared with 1% CS group. These results suggested that changing the CS concentration in the culture medium could improve the development of in vitro derived bovine embryos.