Effect of season and dietary energy concentration on composition and strength of skin in naked neck fowl

Abstract

1. Two experiments, in spring and summer, were conducted to evaluate the effect of dietary energy concentration on the composition and strength of the skin of naked neck fowl. The heterozygous naked neck birds were also compared with their normally feathered sibs under summer temperatures. 2. The average temperatures were 21.2°C and 27.1°C in spring and summer experiments, respectively. Three concentrations of dietary energy were fed to the birds. The diets used were: a low energy diet of 12.12 MJ ME/kg; a medium energy diet of 12.96 MJ ME/kg; and a high energy diet of 13.79 MJ ME/kg. Two protein concentration per energy treatment, 230 and 200 g/kg, respectively were used from 0 to 3 and 3 to 7 weeks of age. 3. A significant season sex interaction showed that the skin of males had higher protein and collagen and lower dry matter and fat content than that of females, when grown under summer conditions. No sex differences were present under spring conditions. 4. The differences between sexes was not significant in spring but males had stronger skin than females in summer. Neither ambient temperature nor dietary energy concentration significantly affected skin displacement of naked neck birds. 5. In comparing the naked neck and their normally feathered sibs in the summer experiment, it was found that naked neck birds had lower skin fat content and higher skin protein content than normally feathered birds.