标题：Effect of Natural and Chemical Colorant Supplementation on Performance, Egg-Quality Characteristics, Yolk Fatty-Acid Profile, and Blood Constituents in Laying Hens
摘要：Natural and chemical colorants are attracting a lot of attention as sustainable feed additives due to their effect on food color and because presentation matters to consumers. Color also is a major sensory factor that helps consumers determine food quality and its possible health benefits. For example, highly colored egg yolks can only come from healthy laying hens fed a well-balanced, nutrient-rich diet. Consumers associate an intense yolk color with healthy, nutrient-rich food. There is a growing market request for eggs with rich yolk coloring. The purpose of the current study was to evaluate the impact of natural (paprika) and chemical (carmoisine) colorant supplementation on the performance, egg-quality characteristics, yolk fatty-acid profile, and blood constituents in laying hens. A total of 240 Bovans laying hens were randomly distributed in a completely randomized design in four treatments according to four experimental diets: a control diet (without supplementation of any colorants), a control diet supplemented with 4 kg/ton paprika, a control diet supplemented with 150 g carmoisine/ton, and a control diet supplemented with a combination of 4 kg/ton paprika plus 150 g carmoisine/ton, fed from 42 to 54 weeks of age. Each treatment consisted of 10 replications with six hens. Dietary inclusion of paprika colorant improved (<i>p</i> < 0.05) the feed-conversion ratio and egg-production rate, while final body weight, weight change, feed intake, and egg weight and mass were not affected. The degrees of egg yolk and white were increased (<i>p</i> < 0.05) by the dietary supplements. Yolk color and shell thickness were enhanced (<i>p</i> < 0.05) by adding paprika and/or carmoisine colorants. Supplementation of the paprika colorant alone or in combination with carmoisine increased (<i>p</i> < 0.05) linolenic acid, oleic acid, and vitamin E concentrations in egg yolks. In contrast, egg yolk palmitic acid and liver malondialdehyde contents were decreased (<i>p</i> < 0.05). Paprika and carmoisine colorants and their combination improved (<i>p</i> < 0.05) blood lipid profile in treated hens. We concluded that the dietary supplementation of natural (paprika) colorants has an influential role in improving egg yolk color, production performance, and egg yolk fatty-acid profile in laying hens.
