Ingredients which are potential oxidizing agents, such as minerals and certain fatty acids, has been shown to reduce piigmentation.
The yellow/orange color of the yolk is controlled by the bird's intake of xanthophyll pigments. As the level of dietary xanthophyll increases, there is increase in yolk color as assessed on Roche Scale of 1 to 15. The desired yolk color will vary in different markets, although a color score of 8-9 is common in many areas.
There are a number of dietary and management factors which can reduce the effective deposition of xanthophylls in the yolk.
High levels of vitamin A, as sometimes used during water medication for varios stress situations, have been shown to cause temporary loss in yolk color pigmentation. High enviromental temperature, coccidiosis, and aflatoxin contamination of feed also implicated in production of pale colored yolks.
In most markets it is important to control and maintain the color of the yolk. The desired yolk color will vary in different markets, Although a color score of 8 -9 is common in many areas.
The yellow/orange color of the yolk is control by the bird intake of xanthophylls pigment and in particular lutein, zeaxanthin and various synthetic pigment such as canthaxanthin and apoarotenoic esters. As the level of dietary xanthophylls increase, there is increase in yolk color as assessed on the Roche Scale of 1 to 15.
The desired yolk color will vary in different markets, although a color score of 8 - 9 is common in many areas. A high degree of pigmentation is a score of 11 - 12 while for some specially pasta markets, there may be need to achieve 14 - 15.
In most markets, it is common to add 7 - 8 g of supplemental xanthophylls per tonne of feed. Levels below 5 g/tonne usually result in too pale yolk
The red/orange colors can be produced by adding synthetic such as canthaxanthin, although usually this degree of coloring is unacceptable to most consumers.
- Causing Agents
- Oxidative breakdown of Carotenoids in Diet or Inadequate Pigment Ratios in Diet
- Affected Systems/Organs
- Internal Egg quality
- Mainly Affects
- Yolk Egg Quality, Yolk pigmentation
- Adequate xanthophylls source or storage. Adequate addition of antioxidant in the diet. Yolk colour seems to be enhance when high levels of vitamin E are used, and when the diet contains antioxidant. Xanthophylls levels below 5g/tonne usually result in too pale a yolk. Check that a source of carotenoids is available in feed. Adequate levels supplemental xanthophyll in the diet . Levels below 5 g/tonne usually result in too pale yolk
- Suggested Actions
- Technical assistance recommended
- Can be managed with feed additives, off-the-shelf medications
- Diagnosis should be confirmed with rapid assays and/or a certified laboratory
Impact on Egg quality
Impact on Liveability
Impact on Production
Overall Economic Impact
Y.M. Saif.2008.Disease of Poultry. 12th Edition.
Mark Pattison, Paul F. McMullin, Janet M. Bradbury. Dennis J. Alexander. 2008. Poultry Diseases. 6th Edition.
Paul McMullin. 2004. A pocket Guide to Poultry Health and Disease. First Edition.
Steven Leeson, John D. Summers. 2008. Commercial Poultry Nutrition. Third Edition.
Donald D. Bell, Williams D. Weaver. 2009. Commercial Chicken Meat and Egg Production. Fifth Edition.