An experiment was conducted to evaluate the effects of different levels of pigment in diets, containing three sources of fat, with or without enzyme, on egg yolk color and laying hens’ performance. All the diets were isocaloric and isonitrogenous. This experiment was arranged in a completely randomized design (CRD) with a 3×2×3 factorial arrangement. The experiment consisted of 18 treatments with three replicates containing 6 Hy-line W36 laying hens from 23 to 31 weeks of age. The treatments consisted of three basic diets containing sunflower oil, tallow and fatty acids with or without enzyme and three levels of pigments (0, 1100 ppm red with 125 ppm yellow pigment, 1500 ppm red with 225 ppm yellow pigment). The different traits were evaluated daily or periodically. The main effect of pigment levels, enzyme and sources of fat as well as their interaction on egg production, egg weight and feed conversion were not significant. Main effect of pigment, sources of fat and enzyme for these traits were not significant either (P>0.05). The main effect of pigment level, enzyme and sources of fat as well as their interaction on blood cholesterol were not significant (P>0.05), but the differences between averages of three sources of fat were significant (P<0.05). Tallow with an average of 188.78 mg/dl had the most and fatty acid with the average of 146.46 mg/dl exhibited the least effect on blood cholesterol. The main effect of pigment and enzyme as well as their interaction on egg yolk cholesterol was not significant (P>0.05), but the main effect of fat on yolk cholesterol was significant (P<0.05). The effect of sunflower oil on yolk cholesterol was the highest while tallow the lowest. Analysis of variance for the main effect of pigment showed a significant effect on yolk color during the first week (P<0.05). The lowest score of color belonged to zero level of pigment (3.33) and the highest to the second and third levels of pigment (10.67). The significant effect of pigment continued until the end of the experimental period. Main effect of enzyme on yolk color was not significant (P>0.05), while the main effect of fat on yolk color was significant (P<0.05). The highest score of yolk color at the end of trial belonged to tallow (9.06) and the lowest to fatty acid (8.28).
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