Carotenoid Status of Poultry Egg under Different Feeding System in Bangladesh

Abstract

Background and Objective: In developing countries consumers and producers do not considere an egg for internal quality, but it would be a good source of micronutrients including carotenoids. This study was conducted to obtain information on the carotenoid content and its different components of egg yolk of some poultry species. Methodology: To evaluate the situation 120 eggs were collected from (1) Native chicken (scavenging), (2) Native chicken (semi intensive), (3) Zending duck (semi intensive), (4) Fayoumi chicken (intensive), (5) White-cross chicken (intensive) and (6) White Leghorn chicken (intensive). After breaking the eggs and removing the albumen, the yolk content taken and mixed properly. The visual colour was assessed using a Hoffmann La Roche yolk fan (0 to 15, where higher values as higher colour) and three co-ordinate colour parameters (L-lightness, a*-redness and b*-yellowness) measured by Minolta Chroma Meter. Egg yolk was analysed for total carotenoids following iCheck⁽™⁾ and AOAC methods. Quantification of lutein, zeaxanthin, canthaxanthin, apo-ester, β-carotene and their isomers done by High Performance Liquid Chromatography (HPLC). Results: It was found that the commercial diets contained very low amounts of carotenoid components (0.18, 0.27, 0.07 and 0.03 mg kg^–1 lutein, zeaxanthin, β-cryptoxanthin and β-carotene, respectively), which also reflected in the colour parameters (RYCFS: 7; L*: 56; a*: -0.15 and b*: 34) of egg yolk. In general, the carotenoid status of yolk from different feeding system varies significantly (21.4 to 34.3 mg kg^–1 yolk), but eggs from scavenging and semi intensive birds found to be rich in lutein (8.0-11.8 mg kg^–1 yolk). Alternatively, eggs from intensive birds contained higher amount of zeaxanthin (4.9-6.3 mg kg^–1 yolk). Values obtained iCheck was slightly lower than AOAC method but found higher than obtained by HPLC although their relationship found to be 0.95 and 0.91 with iCheck data. Conclusion: Therefore, it may concluded that the egg yolk of scavenging and semi intensive birds would be good source of lutein; however, carotenoid content especially lutein concentration in the diets for commercial birds should increase to enrich the carotenoid status of eggs which would be assessed by simple, cost effective and laboratory independent iCheck⁽™⁾ method.