Effect of charcoal:dextran stripped fetal bovine serum on in vitro development of bovine embryos

This study investigated the ability of charcoal:dextran stripped fetal bovine serum (CDS FBS) and heat-inactivated fetal bovine serum (HI FBS) to support in vitro development of bovine embryos. The developmental ability and quality of bovine embryos were determined by assessing their cell number, lipid content, mitochondrial activity, gene expression, and cryo-tolerance. The percentage of embryos that formed a blastocyst was significantly (P < 0.05) higher in medium containing CDS FBS than in medium containing HI FBS (42.84 ± 0.78% vs. 36.85 ± 0.89%, respectively). Furthermore, the beneficial effects of CDS FBS on embryos were associated with significantly (P < 0.05) increased mitochondrial activity, as identified by MitoTracker Green, as well as a reduced intracellular lipid content, as identified by Nile red staining, which increased their cryo-tolerance. Quantitative reverse transcription PCR showed that the mRNA levels of acyl-CoA synthetase long-chain family member 3, acyl-coenzyme A dehydrogenase long-chain, hydroxymethylglutaryl-CoA reductase, and insulin-like growth factor 2 receptor were significantly (P < 0.05) increased upon culture with CDS FBS. Moreover, the mRNA levels of sirtuin 1, superoxide dismutase 2, and the anti-apoptotic gene B-cell lymphoma 2 in frozen-thawed blastocysts were significantly (P < 0.05) higher in the CDS FBS-supplemented group than in the HI FBS-supplemented group, whereas that of the pro-apoptotic gene BCL2-associated X protein was significantly lower. Taken together, these data suggest that supplementation of medium with CDS FBS improves the in vitro developmental competence and cryo-tolerance of bovine embryos.