Skin pigmentation in broiler chickens fed various levels of metabolizable energy and xanthophylls from tagetes erecta

Abstract

Two experiments were conducted in broilers raised by sex from 21 to 49 d of age to analyze some factors that affect skin pigmentation. In the first experiment, the effect of feeding broilers 85 ppm of xanthophylls (Xa) from Aztec marigold flowers (Tagetes erecta) and 4 levels of ME (2,800, 3,000, 3,200, and 3,400 kcal/kg) was evaluated. In experiment 2, the objective was to study the effect of feeding 65 ppm of Xa to broilers from 1 to 21 d of age and 4 feeding regimens thereafter: 1) 75 ppm of Xa from 21 to 49 d; 2) 108 ppm of Xa from 35 to 49 d; 3) 141 ppm of Xa from 35 to 49 d; and 4) 162 ppm of Xa from 35 to 49 d. In experiment 1, there was a significant linear effect (P < 0.01) of dietary energy level on the skin pigmentation of live birds (R2 = 68.8%). It was observed that for every 100 kcal/kg increase in ME, skin b+ (yellowness) values increased by 0.13 yellowness units (YU)/d, and by 2 YU at the end of the study. Furthermore, on the basis of consumption time, females gained 1.77 YU for every YU gained by males, and gained 3.77 YU more than the males at the end of the study. In experiment 2, birds fed 75 ppm of Xa from 21 to 49 d had a daily gain of 0.59 YU, and the females had 1.5 YU more than the males at the end of the study. In treatments 2, 3, and 4, a daily reduction of 0.11 YU in skin pigmentation occurred when the birds did not consume dietary pigment from d 21 to 35. This loss was greater in females at 35 d. At the end of the study, the females gained 1.73 YU more than did males. We observed that it is possible to reach more than 18 skin YU values in vivo when feeding higher concentrations of dietary Xa (from Aztec marigold flowers) from 35 to 49 d of age. © 2012 Poultry Science Association, Inc.