Comparison of marine algae (Spirulina platensis) and synthetic pigment in enhancing egg yolk colour of laying hens.

The objective of this experiment was to determine the effects of dietary marine algae (Spirulina platensis) on egg yolk colour, and compare the effectiveness of Spirulina and synthetic pigment in enhancing egg yolk colour of laying hens fed on a wheat-based diet. In total, 160 Hy-line W36 laying hens of 63 weeks of age were studied by dividing them into 5 groups, 32 birds in each. Except for the control group (based on wheat and soyabean meal), the feed for three other groups contained 1·5, 2·0 and 2·5% of Spirulina; while one group contained synthetic pigments (BASF Lucantin® yellow: 30 mg/kg, and BASF Lucantin® red: 35 mg/kg). Egg production, feed intake, feed conversion ratio (FCR), egg weight and egg yolk colour were determined. A significant increase in egg yolk colour was observed in the treatments that received the Spirulina and synthetic pigment, compared with the control diet. There were no significant differences between the treatments with 2·5% Spirulina and synthetic pigment in enhancing egg yolk colour. Finally, the results indicated that the diet containing 2·5% Spirulina could be as effective as the diet with synthetic pigment in producing an agreeable egg yolk colour.