Comparison of several enzymes between normal physeal and tibial dyschondroplastic cartilage of broiler chickens.

Normal physeal and dyschondroplastic cartilage of broiler chickens was examined for six enzymes by isoelectric focusing in thin-layer polyacrylamide slab gels. Acid phosphatase (ACP), esterase (EST), malate dehydrogenase (MDH), and peroxidase (PRX) were present in the normal physeal cartilage but not in the dyschondroplastic cartilage. Staining intensity of glucose-6-phosphate isomerase (GPI) and triose-phosphate isomerase (TPI) was reduced in the dyschondroplastic cartilage compared with that of the physeal cartilage. Differences in the presence of these enzymes possibly demonstrated their roles in processes of bone formation, cartilage resorption, and calcification. ACP could be involved in calcification. Lack of EST and PRX may be related to the failure of vascular invasion in dyschondroplastic cartilage of afflicted birds. A deficiency of MDH and reduced GPI and TPI in dyschondroplastic cartilage may reflect a reduction in the activity of energetic metabolism, causing the dissipation of energy and necrotic cells.