Effect of Dietary Crude Protein and Lysine on Feather Growth in Chicks to Twenty-One Days of Age

A study was conducted to evaluate feather development in male broiler chickens fed variable levels of dietary CP and lysine. Diets contained 170, 210, 250, or 290 g of CP/kg with 0.86, 1.22, 1.34, or 1.46% lysine, each being fed to 2 replicate groups of 4 chicks. Dietary CP per se had a significant effect on feather weight and feather nitrogen gain. Increasing dietary CP from 170 to 250 g of CP/kg of diet increased feather weight and feather nitrogen gain. No differences were found at higher dietary CP levels. Dietary lysine levels from 0.86 to 1.46% did not affect feather weight, feather nitrogen gain, or feather:body weight in male chicks to 21 d. However, feather weight and feather nitrogen gain decreased as lysine increased in diets with 170 and 210 g of CP but not with 250 or 290 g of CP/kg. Percentage of total feather nitrogen was also influenced by the level of dietary lysine in diets containing 210 and 250 g of CP/kg. Feather development was more influenced by dietary CP per se than by levels of lysine.