Turmeric powder (TP) used in this study was provided by
Easy Bio System, Inc. (Seoul, Korea). The chemical composition of TP was as following; carbohydrate, 69.4%; crude protein,
6.3%; ether extract, 5.1%; moisture, 13.1%; minerals,
3.5% and curcumin, 2%. A total of two hundred 60-wk Lohmann
brown layers were randomly divided into 4 treatments
with 5 replicates of 10 birds per treatment in wire cage. The
layers were fed one of following four diets containing 0, 0.1,
0.25 or 0.5% TP, respectively, for 7wks (Table 1).