Pyruvate carboxylase activities in red blood cells and liver of chicks and their dependency on biotin status. First results with activation assays.

Pyruvate carboxylase activities of erythrocytes and liver preparations and their in vitro stimulation by biotin were used for the determination of the biotin status of chicks. Reasonable stability of the enzyme in erythrocytes was achieved when storing the erythrocytes deep-frozen in a glycerol-containing medium. Results of the activation assays in erythrocytes and liver are compared with biotin levels in feed, plasma and liver. The pyruvate carboxylase activation assay appears to be a useful tool for assessing the biotin status of chicks.