Oxidative Breakdown of Carotenoids or Inadequate Pigment Ratios in Laying Hens
Ingredients which are potential oxidizing agents, such as minerals and certain fatty acids, has been shown to reduce pigmentation.
The yellow/orange colour of the yolk is controlled by the bird's intake of xanthophyll pigments. As the level of dietary xanthophyll increases, there is an increase in yolk colour as assessed on Roche Scale of 1 to 15. The desired yolk colour will vary in different markets, although a colour 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 various stress situations, have been shown to cause a temporary loss in yolk colour pigmentation. High environmental temperature, coccidiosis, and aflatoxin contamination of feed also implicated in the production of pale coloured yolks.
In most markets, it is important to control and maintain the colour of the yolk. The desired yolk colour will vary in different markets, Although a colour score of 8 -9 is common in many areas.
The yellow/orange colour of the yolk is control by the bird intake of xanthophylls pigment and in particular lutein, zeaxanthin and the various synthetic pigments such as canthaxanthin and apocarotenoid esters. As the level of dietary xanthophylls increases, there is an increase in yolk colour as assessed on the Roche Scale of 1 to 15.
The desired yolk colour will vary in different markets, although a colour score of 8 - 9 is common in many areas. A high degree of pigmentation is a score of 11 - 12 while for some especially pasta markets, there may 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 a too pale yolk
The red/orange colours can be produced by adding synthetic such as canthaxanthin, although usually, this degree of colouring is unacceptable to most consumers.
Observed Clinical Signs Happenings
Internal Egg quality
- Yolk Mottled, flaccid and fragile or Flecked Yolk (a very limited amount of mottling is normal)
- Yolk colour Abnormal
- Yolk colour variable
- Pale yolks or yolk colour decreased or yolk discolouration
Oxidative Breakdown of Carotenoids or Inadequate Pigment Ratios in Laying Hens DOES NOT show or exhibit or manifest any of the following clinical signs happenings:
- Egg drop
- Mortality above the standard
- Visibly sick birds
- Flock behaviour activity change
- Droppings abnormalities
- Respiratory abnormalities
- Neurological Nervous
- Lameness or unusual movements, incoordination, reluctance to move
- Eyes abnormalities
- Head, Comb, Wattles, Face, Nostrils, Sinuses, Mount, Beak, Earlobes, abnormalities (except eyes)
- Body Parts (Neck, wings, breast, abdomen, shanks, legs, hocks, feet, joints, vent, and skin, abnormalities), skinny body, retarded growth, weight depression
- Feathers abnormalities
- Feed Consumption Changes
- Feed intake reduced or refusal
- Diet or Feed Changes (Recent Feed delivery, Recent formulation /diet, Other silo or improper storage, another feed brand)
- Shell quality
- 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
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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.