USE OF XANTHOPHYLLS IN POULTRY FEED FOR EGG YOLK & SKIN COLOUR PIGMENTATION
by-DR. RAJESH KUMAR SINGH, (LIVESTOCK & POULTRY CONSULTANT), JAMSHEDPUR, JHARKHAND,INDIA 9431309542, rajeshsinghvet@gmail.com
Colour is one of the most important factors affecting consumer choices through sensory evaluation of foods. In most countries, golden yolks are preferred because good colour has been traditionally associated with high health. Also, eggs used in recipes can influence the colour of pasta, bakery products and sauces. In addition, although consumer preference for broiler skin colour varies according to culture and region, here also, good health is generally associated with golden skin colour.
It is a common practice to color egg yolks by adding pigments in the diet of layers. In fact, this phenomenon in nature is as old as the very animal kingdom. Carotenoids, and more specifically xanthophylls (carotenoids containing oxygen atoms within their molecules) give the egg yolk its natural color. Carotenoids also lend feathers their red, orange and yellow hues in many bird species, which has been identified as a sign of health and reproductive eligibility. In traditional and self-feed farming systems, xanthophylls, primarily lutein and zeaxanthin, are present in dietary components such as corn, wild flowers, green vegetables, fruit, insects, etc. The main xanthophylls are lutein and zeaxanthin, which are present in corn, wild flowers, green vegetables, fruit, and insects, among others.
Modern poultry production has brought about continuous improvements in output levels and feed conversion, as a result of genetic, management and health enhancements. However, this means that for every egg produced, layers take up less carotenoid from raw materials. This makes it necessary to balance out the levels supplied in the diet by additional supplementation. In addition, direct supplementation of carotenoids has enabled unrestricted use of raw materials lacking significant levels of xanthophylls. The use of such external sources also guarantees lower variability of egg yolk pigmentation levels among animals and throughout their productive lives. The use of these xanthophyll supplements had led to renewed interest in the egg as an excellent source of highly bioavailable xanthophylls, which are otherwise not produced endogenously and must be taken up from the diet.
The poultry industry was and is still suffering from severe challenges because of the increasing prices of soybean meal and yellow corn which are mainly used in formulating poultry diets. Therefore, there is an urgent need for nutritious and affordable alternatives. To reduce costs, the best strategy is to formulate diets using alternative and locally available ingredients such as distillers dried grains with soluble. Distillers dried grains with solubles (DDGS) is a co-product of ethanol-producing plants that use corn and wheat for manufacturing . It is a rich source of crude protein, amino acids, crude fat, and minerals as well as non-starch polysaccharides (NSP) in poultry diets. However, monogastric animals do not efficiently digest feedstuffs that are high in NSP.
Eggs are a staple food in human diet and have a natural balance of essential nutrients. Eggs have a high nutritional value and provide consumers with cheaper animal protein than other foodstuffs (e.g., meat and milk). Measurements of external and internal egg quality can be beneficial to producers since they provide information on the outcome of the egg production process, and reflect the health condition of the flock. Yolk color is of great importance in terms of consumer expectations in different European countries, with varying demands for yolk color between light yellow and deep orange. Yolk color is affected by various components provided in feed ingredients and feed additives .
Carotenoids are natural compounds present in animals and plants; with yellow, orange and red typically associated with birds. It is well known that birds are not able to synthesise carotenoids, and thus these essential compounds must come from their diet. Carotenoids are mainly found in the egg yolk, the skin and fat, the liver, and the feathers. They are essential not only for pigmentation, but also for immunomodulation as antioxidants, evidenced by the high disappearance rate of carotenoids from the blood stream during immune stress periods, and reduced pigmentation throughout the body.
Pigments that impart a yellow or orange color to egg yolk belong to an oxycarotenoid group called xanthophylls. The most important xanthophylls for egg yolk coloration are zeaxanthin and lutein. The former is causing egg yolks to be more orange-red in color, while lutein imparts a more yellow hue. The balance between these two major xanthophylls is what determines final color in egg yolks. Equally important to this balance is the total xanthophyll concentration in feed. As a rule of thumb, to achieve a satisfactory saturation of color, the feed must contain at least 15-20 ppm total xanthophylls.
From among commonly available ingredients, maize is considered a good source of xanthophylls (20 ppm), followed by the less frequently encountered but very powerful maize gluten meal (275 ppm), and the infrequently used alfalfa meal (175 ppm). Maize and maize gluten meal are rich in zeaxanthin (4 ppm in whole maize), whereas alfalfa meal is rich in lutein (64 ppm). An unusual source of natural xanthophylls is marigold petal meal, which was added quite frequently in commercial feeds before the advent of synthetic pigments. The concentration of xanthophylls in Marigold petal meal is 7000 ppm. More recently, the use of certain algae as a source of natural pigments has been investigated as it was found they can contain up to 2000 ppm xanthophylls.
CAROTENOIDS IN LAYERS———-
Consumers associate intense yolk color with high egg quality and freshness. This perception is based on the popular knowledge that diseased hens absorb carotenoids poorly from the diet and lay eggs with pale tones. The use of these xanthophyll supplements had led to renewed interest in the egg as an excellent source of highly bioavailable xanthophylls, which are otherwise not produced endogenously and must be taken up from the diet.
Egg yolk color can be assessed subjectively by means of color scales, such as the Roche Yolk Color Fan (RYCF), which comprises 15 categories, with a score of 15 indicating maximum pigmentation. A more technical approach is to use reflectance colorimetry and apply a three-dimensional scale based on the CIE system (defining lightness or L*, yellowness or b*, and redness or a*). Intense orange colors make eggs more desirable for consumption to a vast majority of consumers; however, there are considerable differences in preference, which are strongly linked to historical and cultural factors. Indeed, in the European Union, consumers in Spain, Italy, Germany and France generally prefer deeply colored eggs (RYCF 12-13). Also, intensely colored eggs are highly demanded by the food industry for products such as pasta, pastries, sauces, etc. Good yolk pigmentation requires a base of so-called “yellow xanthophylls” (lutein; beta-apo-8’-carotenoic acid ethyl ester or apo-ester) and “red xanthophylls” (capsanthin; canthaxanthin), which can be used to attain a wide range of orange hues according to consumer preferences in each market.
NATURAL PIGMENTS——
Key natural pigments include marigold (Tagetes erecta) flower extract, which is rich in lutein and zeaxanthin, and red pepper or paprika (Capsicum annuum) extract, which is rich in capsanthin.
SYNTHETIC OR NATURAL IDENTICAL PIGMENTS———
Canthaxanthin and beta-apo-8’-carotenoic acid ethyl ester (apo-ester) are the most relevant synthetic xanthophylls in poultry. They are produced from acetone and β ionone (Isler et al., 1967). These xanthophylls are found in free forms and are included in matrices of saturated fatty acids and antioxidants for protection and stabilization. Sometimes these carotenoids produced entirely by chemical synthesis are linked to the term ‘natural’ when described as ‘natural-like’ or ‘natural identical’, but this should not be misleading.
PIGMENTATION EFFICACY——-Carotenoids are absorbed in the small intestine along with other lipid components and are transported by lipoproteins in the blood to the target tissues where they deposit — the egg yolk in layers.
NB-
1.PIGMENTATION SHOULD BE BASED ON BOTH RED AND YELLOW XANTHOPHYLLS TO ADJUST TO REAL CONDITIONS OF COMBINED USE IN THE POULTRY INDUSTRY.
2. XANTHOPHYLLS FROM VEGETABLE EXTRACTS ADD NUTRACEUTICAL VALUE TO THE EGG BY INCREASING THE LEVELS OF LUTEIN IN COMMERCIAL EGGS BY UP TO 7 TIMES
3. EGG LUTEIN IS RECEIVING RENEWED INTEREST FOR ITS USE IN NUTRITIONAL SUPPLEMENTS GIVEN ITS BENEFITS AS A FUNCTIONAL FOOD
Legal framework of the use of pigments———–
The addition of natural and synthetic carotenoids in layer feeds in the European Union is currently limited to 80 ppm (mg/kg). The only exception is canthaxanthin, which is limited to 8 ppm in layers. This restriction aims to prevent the unwanted effects of excessive exposure in humans, as excessive levels of canthaxanthin can lead to the development of precipitated crystals in the retina (Arden et al., 1991; Baker, 2001). The use of carotenoids derived from vegetable extracts has been criticized by some in favor of synthetic carotenoids, simply because vegetable crops are exposed to potential contamination by environmental pollutants (dioxins, heavy metals, pesticides, etc.).
Pigmenting eggs and broiler chickens———
In addition to their metabolic functions, carotenoids play an important role in poultry farming in many countries.
How can they be used in different regions to create the optimal color of egg or broiler chicken skin that consumers expect?
Carotenoids in nature———–
Birds and mammals are unable to synthesize carotenoids, and therefore rely upon food sources to obtain them. In the wild, birds do this by consuming seeds, insects and molluscs, so that the carotenoids are absorbed and deposited (depending on gender) in different organs. In male birds, carotenoids are deposited in the feathers, giving them the coloring that allows them to stand out and attract females (and predators). Only the healthiest males can display these bright colors, as carotenoids need to be ingested, absorbed and deposited. As a result, there needs to be mobility, intestinal integrity and also immune integrity in order for the birds not to have to use carotenoids as antioxidants or as sources of vitamin A1.
Females (according to the species), on the other hand, need to keep a low profile to avoid attracting predators. As such, they deposit all carotenoids in the fat and in particular in the ovaries, where they are converted into a source of antioxidants, enabling the future embryo to avoid the oxidative stress associated with the transformation from fertilized egg to chick.
History of Use of carotenoids in poultry farming—————-
The use of carotenoids for modifying bird parameters began with a non-domestic species. In the mid-20th century, flamingos kept in captivity were not reproducing effectively and or preserving the pink color that was so characteristic of their cousins in the wild. Biologists from Basel Zoo collaborated with scientists from Hoffmann-La Roche and discovered the diet of animals in captivity was lacking the carotenoids necessary for reproduction, so they set themselves the task of supplementing canthaxanthin in specimens. As a result, this became the first group of flamingos in the world to breed in captivity and retain the color that characterizes their cousins in the wild3.
On the other side of the Atlantic, the emerging Mexican poultry business was facing consumer rejection. As poultry farming became industrialized, the change from yellow corn to sorghum caused eggs and chickens to lose their distinctive pigmentation, leading consumers to reject the new farm-reared chickens and egg yolks with their inferior shade. A group of Mexican scientists led by Dr. Sergio Brambila from the National Institute of Livestock Research (INIP, now known as INIFAP) was tasked with solving the problem. Using alfalfa was one possibility, but it was expensive and impractical.
Dr. Brambila and the chemist Carmen Mendoza found that Aztec marigold, a rich source of the carotenoids lutein and zeaxanthin, provided a cheap and readily available alternative for adding pigment to chicken and egg yolk4,5. This sparked the beginning of the multi-million dollar marigold flower industry, today the primary source of lutein for animal and human consumption.
Metabolic functions————-
Carotenoids perform a number of important metabolic roles; acting as visual communicators through mimicry and coloration, vitamin A precursors, immune modulators and antioxidants. The carotenoid structure can determine its function. Those with nine or more conjugated double bonds possess superior antioxidant properties. It has been proven that eggs containing canthaxanthin possess superior antioxidant capacity than those without6. In addition, chicks from hens fed with canthaxanthin have macrophages with a superior bactericidal capacity and therefore improved immune function7.
Egg yolk pigmentation——————–
Preferences for a certain yolk color are highly variable depending on the given culture and country. Some market research studies conducted over the last decade indicate that in several cultures there is a preference for dark orange-colored yolks as a reflection of the product’s internal quality. In the studies mentioned, yolks with a dark orange shade are preferred in up to 60% of cases in various countries across Europe, America and Asia. The consumer associates the yolk’s intense color with an egg that is fresh and rich in nutrients. What is certain is that a pigmented egg will always come from a healthy hen8, as compromised nutrient absorption results in a loss of pigmentation in hens and broiler chickens.
Another important factor in some markets is the use of carotenoids to differentiate between eggs from certain brands or with certain nutritional properties. In a recent study in Beijing, it was discovered that for every unit of increase in YolkFan™, the price rose by 0.18 RMB (approx. $0.025) per egg. In other countries and markets, it is also common to increase pigmentation for products enriched with omega 3 or free from antibiotics. In India, the yolk color is displayed on the egg brand’s external packaging.
The most commonly used carotenoids for egg pigmentation are canthaxanthin and paprika extracts for the red base, while apo-ester and lutein/zeaxanthin (marigold, or targets) are used for the yellow base. Corn and its co-products (gluten, DDGS) are recognized as a good source of carotenoids (particularly lutein/zeaxanthin).
The recommendations are clearly established and guide a process that can be followed without any major obstacles, providing that:
1. The exact carotenoid content of various sources is known.
2. The formulation is determined and adjusted to consider losses during the process. The important value is what the bird has in its feed trough.
3. An optimal mixing process is maintained. It is preferable to incorporate pigments in the premix.
4. Animals are kept free of health problems.
These are essential to ensure eggs command the highest value and maintain brand reputation and quality standards. The source of carotenoids must be stable, consistent and demonstrate good bioavailability.
Chicken pigmentation—————–
In very specific markets, chicken skin color is very important and considered a symbol of quality, freshness and nutritional value. In markets such as Mexico, Spain, France, Italy and China, chickens are sold with skin color variations ranging from yellow to golden orange. In broiler chickens, carotenoids are primarily deposited in the feet, skin and subcutaneous fat. Slaughter and plucking conditions are also very important. The carotenoids used for skin pigmentation are canthaxanthin for the red base, and apo-ester and lutein/zeaxanthin for the yellow base. Pigmentation recommendations are very varied and depend on regional and market requirements. However, the common denominator in consumer demand is color homogeneity.
In Europe, a system based on a fan10 is used which serves as a standard for setting targets and evaluating them, as well as a formulation program that considers the carotenoid sources available in order to achieve various pigmentation targets. The program is perfectly adapted to European and Asian conditions of medium pigmentation and is a well established method.
In order to be able to pigment chickens successfully, all the above mentioned precautions mentioned for eggs must be followed, in addition to the following specific guidelines for chickens:
1. The scalding temperature must be kept below (but close to) 54°C.
2. Pigment carotenoids must be present in the feed for at least three weeks prior to slaughter.
3. In the summer, consumption must be monitored and adjustments made to the formulation so that pigmentation is not affected. In some conditions, carotenoids can be used in the drinking water in order to fortify it.
Colour deposition in the skin—————
In broilers, zeaxanthin influences the yellow value in all tissues, more noticeably in the abdominal fat, with lutein and zeaxanthin being deposited in skin and fat with a rate of 8-12% and 4-9%, respectively. In broilers, the deposition of the isomerised tagetes (enriched in zeaxanthin) is lower than the standard tagetes (mostly lutein), whereas contents of apo-carotene-ester increases in skin and abdominal fat with increasing supplementation of this carotenoid, reflecting a linear increase over the entire dose range (not common among other carotenoids).
It has been determined that 1 ppm of apo-carotene-ester is equivalent to about 2 ppm of lutein-zeaxanthin (from tagetes). Canthaxanthin is the dominating red carotenoid in pigmented broilers, whereas paprika receives little attention because of its low efficiency (requiring two to three times the amount of paprika xanthophylls compared to canthaxanthin).
Pigmentation evaluation—————
Measuring color it is always a case of evaluating something subjective which depends on reflected light, the color of the surroundings, the light present and the observer’s eye. However, procedures have been refined over the course of the last and current century, and will continue to be refined over time.
The DSM Yolk Fan™ is the reference standard for setting egg pigmentation targets. It is easy to use, effective and economical. Even though there may be variations between observers, it also provides a universal language for talking about color. This tool is also used in several markets to measure foot pigmentation.
Conclusion
In order to get the maximum value for your eggs and boost the consumer experience, use safe and reliable carotenoids in the feed.
Flavour Trove animal health have developed a system that allows precise control of pigmentation through the tailored and controlled addition of carotenoids – naturally occurring biological pigments that can be added to the feed.The product is NatuXan-Y
Description of NatuXan-Y
NatuXan-Y is a natural yellow pigment based on natural xanthophylls, extracted
from Tagetes erecta that delivers consistent uniform colour to the egg yolk and broiler skin.
It contains a minimum of 20 gms/kg of Xanthophylls to enhance the colour of egg yolk and broiler skin.
Appearance : Yellow Ochre, free flowing powder
Odor : Marigold characteristics
Saponification : >98
Bulk density : 0.90 – 0.65 g/ml
Packaging : 20 kgs
Shelf life : 24 months from manufacturing date when stored as directed
Store in a cool, dry place tightly sealed protected from light, moisture and heat.
Easy to handle and apply
Completely Natural & Safe
Improves the nutritional value of eggs
Serves as an antioxidant
Efficient absorption which promotes high bioavailability
Can be used in combination with NatuXan-R
NatuXan-Y does not affect any other ingredients in the diet due to its inert characteristics
FEEDING INSTRUCTIONS : POULTRY
Mix with finished feed at a rate of :Feeding rate is established in accordance with the desired
pigmentation level or as per the recommendation of a qualified nutritionist.
Layers 500 to 2000 gms per ton of feed Broilers 1000 to 2000 gms per ton of feed %
