Abstract
This study was performed to measure the effect of carotenoid polarity on absorption and Pigmentation in blood, muscle, and skin of laying hens. Carotenoids used in this study and Polarity were ${\beta}$-8-Apo-carotenoic acid ethyl ester(ACAEE) ＞ astaxanthin ＞ canthaxanthin ＞ ${\beta}$-carotene. The chickens used in this study were 61∼78 weeks old ISA brown laying hens. Experiment #1 was designed to measure the effect of carotenoid level on the accumulation of carotenoids in carcass of laying hens after feeding for 6 weeks. D-carotene was accumulated in skin only at a detectable level when it was fed at 300 mg/kg feed. The skin was pigmented as yellow when it was measured by colorimeter. The concentration of ${\beta}$-carotene in blood was proportional to that in the feed. Pigmentation of muscle by 9-carotene was not effective. Canthaxanthin significantly increased redness of the skin(p＜0.05). However, canthaxanthin did not pigment muscle. The level of canthaxanthin in the blood and skin increased as the concentration in feed increased. ACAEE at 200 and 300 mg/kg feed significantly increased yellowness of the skin(p＜0.05). At all levels of ACAEE used($\geq$50 mg/kg feed) the b values of colorimeter increased. With increases in the contents of ACAEE, the concentration of ACAEE in the blood and skin increased. Compared to ${\beta}$-carotene, ACAEE and canthaxanthin were absorbed 9- and 3-fold more into the blood, respectively. The concentration of ACAEE and canthaxanthin in the skin was 1/10 of those in the blood. The lower were the concentrations of carotenoids in the feed, the higher were the absorption rates(from feed to blood and from blood to skin) The results indicated that the higher was the polarity of carotenoids, the more effective were the absorption and pigmentation. In experiment #2, the effect of carotenoid levels of feed on the accumulation of carotenoids in each body part of laying hens was determined. The colorimeter values for redness and yellowness significantly increased when canthaxanthin was fed at $\geq$50 mg/kg feed(p＜0.05). Breast and thigh were not affected by feeding of canthaxanthin at the levels used. The L values of muscle but not the a and b values were significantly affected by feeding at $\geq$200 mg/kg feed for wings and breasts, respectively. The yellowness of skin and muscle significantly increased when ACAEE was fed at $\geq$ 100 and $\geq$ 200 mg/kg feed, respectively(p＜0.05).