The Use of Beta-Apo-8′-Carotenoic Acid Ethyl Ester as a Standard for Determination of Xanthophyll Utilization from Natural Sources by Broilers

A synthetic pigment, beta-apo-8′-carotenoic acid ethyl ester, was evaluated as a standard from which xanthophyll utilization by broilers could be determined for various feed ingredients. The ingredients tested were yellow corn, alfalfa meal, corn gluten meal, kenaf meal, marigold meal and canthaxanthin. Xanthophyll utilization from each ingredient was determined by comparison with standard curves developed for beta-apo-8′-carotenoic acid ethyl ester at levels of 5, 10, 20, 30 and 40 grams per ton of feed. Pigmentation measurement of both skin and shanks was accomplished using visual scoring systems and a reflectance colorimeter. It was concluded that beta-apo-8′-carotenoic acid ethyl ester could be used effectively as a standard in xanthophyll utilization studies. Both visual scoring and instrumental determinations of pigmentation appeared to be efficient in determining the xanthophyll utilization values.