The role of commercial bovine serum albumin preparations in the culture of one-cell rabbit embryos to blastocysts

Abstract

Normal bovine serum albumin (BSA) in a complete medium without energy substrates promoted growth of 1-cell embryos to hatched blastocysts. Defatted charcoal-treated BSA did not promote growth to the blastocyst stage but the addition of pyruvate or palmitic and oleic acids allowed blastocyst growth but not blastocyst hatching. Sodium dodecyl sulfate-gel electrophoresis showed that both the normal and defatted BSA samples were heavily contaminated by proteins other than albumin. Normal BSA fractionation on Sephadex G-200 indicated that the property of promoting complete blastocyst hatching was not due to the albumin but was associated with the higher MW fraction of the BSA. Normal BSA extraction with chloroform appeared to destroy the hatching-promoting ability as neither the residue after extraction nor defatted BSA to which the organic extractate had been added promoted complete blastocyst hatching. Evidently, commercial BSA may have at least 2 effects on blastocyst growth: energy provision via albumin-bound fatty acids and promotion of blastocyst hatching by a non-albumin component.