Changes in the physical and chemical properties of skin collagen from broiler chickens exhibiting oily bird syndrome.

Abstract

The mechanical and thermal properties of the skin and some chemical characteristics of the skin collagen have been examined for broiler chickens exhibiting Oily Bird Syndrome (OBS) and compared with material from normal birds. Comparisons of skin thickness showed that there was no significant difference between the two groups. There was also no difference in the melting temperature of the skin collagen between the two groups when examined by the isometric melting method. The strength of the skin was examined at 36 C and at 93 C. At both temperatures, the skin from OBS birds was significantly weaker than skin from normal birds. Skin collagen was examined for birds from OBS flocks (greater than 20% OBS occurrence) without distinction of the characteristics of the individual birds and compared with the skin collagen birds from flocks where OBS was absent. Comparisons of cyanogen bromide-digested collagen from both groups by polyacrylamide gel electrophoresis showed a clear distinction between the groups. The observed differences suggested that a change that lowered the extent of collagen crosslinking was present in the birds from OBS flocks, and this observation is consistent with the weaker mechanical properties of the skin of these birds. All birds in these flocks show the difference even if the individual birds do not all show OBS. This suggests that a change leading to lowering of the structural integrity of the connective tissue is present in all birds in an OBS-affected flock, but that individual variation between birds determines those birds that actually exhibit OBS.