Developmental changes in the activities of peroxisomal and mitochondrial β-oxidation in chicken liver

Abstract

The activities of peroxisomal and mitochondrial β-oxidation and carnitine acyltransferases changed during the process of development from embryo to adult chicken, and the highest activities of peroxisomal β-oxidation, palmitoyl-CoA oxidase, and carnitine acetyltransferase were found at the hatching stage of the embryo. The profiles of these alterations were in agreement with those of the contents of triglycerides and free fatty acids in the liver. The highest activities of mitochondrial β-oxidation and palmitoyl-CoA dehydrogenase were observed at the earlier stages of the embryo; then the activities decreased gradually from embryo to adult chicken. The ratio of activities of carnitine acetyltransferase in peroxisomes and mitochondria (peroxisomes/mitochondria) increased from 0.54 to 0.82 during the development from embryo to adult chicken. The ratio of activities of carnitine palmitoyltransferase decreased from 0.82 to 0.25 during the development. The affinity of fatty acyl-CoA dehydrogenase toward the medium-chain acyl-CoAs (C 6 and C 8) was high in the embryo and decreased with development, whereas the substrate specificity of fatty acyl-CoA oxidase did not change. The substrate specificity of mitochondrial carnitine acyltansferases did not change with development. The affinity of peroxisomal carnitine acyltransferases toward the long-chain acyl-CoAs (C 10 to C 16) was high in the embryo, but low in adult chicken.