Glucose and glycine synergistically enhance the in vitro development of porcine blastocysts in a chemically defined medium.

In the present study, the effects of glucose and/or glycine on the in vitro development of Day 5 (Day 0=IVF) porcine blastocysts were determined. The addition of 2.5-10 mM glucose to the chemically defined culture medium porcine zygote medium (PZM)-5 significantly increased blastocyst survival rates compared with those of blastocysts cultured in the absence of glucose. The addition of 5 and 10 mM glycine to PZM-5 containing 5 mM glucose significantly enhanced the development to hatching and the number of hatched blastocysts compared with no addition of glycine. However, the addition of glycine to PZM-5 with no glucose did not improve blastocyst development. The ATP content of Day 6 blastocysts cultured with glucose was significantly higher than that of blastocysts cultured in the absence of glucose, regardless of glycine supplementation. The diameter and total cell numbers were significantly greater, and the apoptotic index was significantly lower, in Day 6 blastocysts cultured with both glucose and glycine. These results indicate that glucose is an important energy source for the porcine blastocyst and that glucose and glycine act synergistically to enhance development to the hatching and hatched blastocyst stage in vitro.