The document discusses factors that affect the internal quality of eggs. It describes how eggs are formed and the nutritional composition of egg whites, yolks, and whole eggs. Key factors that influence internal egg quality include a hen's nutrition, length of storage and storage conditions, hen strain and age, ingestion of contaminants, and diseases. Nutritional deficiencies or excesses can impact qualities like egg white thickness, yolk color and size. Longer storage causes egg whites to thin as carbon dioxide escapes and pH increases. Younger hens generally produce smaller eggs. Certain diseases and contaminants in feed are also linked to poorer internal quality.

1. DR. K. PRASHANTH KUMAR
FACTORS EFFECTING
INTERNAL QUALITY OF EGG

2. Avian egg is a vehicle for reproduction, it also
serves as a cheapest protein source for humans.
It is well balanced with all nutrients.
Production of good quality eggs i.e. good egg shell
quality and internal quality are two critical
parameters for the economic viability of layer and
breeder industry.

3. Formation of egg

5. o Egg consists of the
Yolk - 30-33%
Albumen- 60%
Shell- 9-12%
o Albumen is a good source of
protein, B5, B2, Cl-, Mg, K, Na
& sulfur and all the egg's zinc.
Absent in vit-C
o Yolk contains all of the fat in the
egg and a little protein.
It also contains A, D, and E.
The yolk also provides vitamin
B12 and folic acid, and the
minerals iron, calcium,
copper and phosphorus.
o All nutrients are highly
bio-available
Nutritive value of an egg (55 g)
Nutrient
Calories
(Kcal)
75
Protein
(gm)
6.3
CHO (gm) 0.6
Total fat
(gm)
5.0
Cholesterol
(mg)
213
Sodium
(mg)
63
Source: FAO

6. o Internal quality parameters are – Albumen quality, Yolk quality,
egg white (albumen) cleanliness and viscosity, size of the air cell,
yolk size, Yolk colour, Mottling of vitelline membrane.
Methods of measuring internal quality parameters:
o Albumen quality: It can be measured in terms of
i) Albumen index,
ii) Haugh unit,
iii) pH of the albumen.
i) Albumen index: The breadth and length of the thick albumen
are measured by slide callipers and height is measured at diff
locations by using a spherometer.
Albumen Index = ( height of albumen/ mean width)×100

7. Spherometer
Vernier calipers

8. ii) Haugh unit: introduced by Raymond Haugh, 1937.
An egg is weighed, then broken onto a flat surface
(breakout method), and a micrometer used to determine the height
of the thick albumen (egg white).
o The higher the number, the better the quality of the egg
(fresher, higher quality eggs have thicker whites).
HU = 100 * log10 (h - 1.7w0.37 + 7.6)
Where HU = Haugh unit, h = height of the albumen in mm,
w = weight of egg in gm
o AA- above 72, A : 71 – 60, B : 59 – 31, C : 30 or less

9. iii) pH of the albumen: The pH of the albumen from a newly laid
egg is about 7.4 to 7.6. During storage the pH of albumen
increases with temperature to a maximum value of about 9.7
(Samli et al. 2005). The rise of the pH is due to the loss of CO2
through the pores of the shell.
Yolk quality: yolk quality parameters are yolk colour, yolk index
, pH of the yolk and air cell size.
Yolk Index: The yolk index was calculated as per Funk (1948).
Yolk index of chicken eggs does not exceed 0.5.
Yolk index = (Max height of yolk/ Max width of the yolk)×100

10. Yolk color: Color of yolk can be directly assessed by
comparing with standard colors in a yolk color rotor or a
yolk color fan.
o A standard colorimetric method -This method is effective
for color produced by xanthophylls pigments from corn
only.
pH of the yolk: The pH of the yolk in freshly laid eggs is
generally about 6.0 but during storage of eggs the pH
gradually increases to between 6.4 to 6.9.
Size of the air cell: size of the air cell increases with the
length of storage period. Size of air cell in freshly laid egg is
about 3-4 mm.

12. Factors effecting internal quality of eggs
• Nutrition
• Length of storage & storage conditions
• Hen strain and age
• Ingestion of contaminants
• Diseases

13. Nutritional factors:
Albumen: Vitamin concentration in the hen diet is the most
important factor in determining vitamin content in the egg. As
vitamin levels in the diet are increased, there is an increase in
vitamin levels deposited in the albumen and /or yolk.
o Riboflavin, folic acid, niacin, thiamine, pyridoxine, pantothenic
acid, biotin, vitamin B12 are well transferred into the egg white
and their concentrations depend on feed concentration
(Leeson and Caston 2003, House 2002).
o Among all vitamins vitamin B12 & pantothenic acid are well
transferred from feed (Zand et al.2011).

14. o Egg white concentration of iodine, selenium and copper are
linked to the levels used into the feed.
o Feeding cotton seed cake results in pink coloured whites due to
the presence of fatty acids i.e malvalic and sterculic acid.
o Deficiencies of vitamin K (probably rare) or vitamin A in diet
increases the chance of Blood spots. Sulfaquinoxaline may
increase incidence if vitamin K is marginal.

15. Yolk : The major fatty acids in egg yolk are oleic acid (C18:1)
and palmitic acid (C16:0). Linoleic acid (C18:2) and stearic acid
(C18:0) are also significant (Romanoff and Romanoff, 1949). The
composition of fatty acids in egg yolk can easily be altered
through dietary intervention to increase the percentage of omega-
3 content.
o One egg may supply almost 12% vitamin A, more than 6%
vitamin D, 9% riboflavin, and 8% panthotenic acid of the
recommended daily allowance (USDA).
o Selenium is found in eggs as selenomethionine, with higher
bioavailability than that of inorganic selenate or selenite (King,
2001)

16. Yolk colour: Yolk color depends on the diet of the hen. yellow-
orange plant pigments known as xanthophylls.
 yellow corn and alfalfa meal lay eggs with yellow yolks.
 white corn, grain sorghum (milo), wheat or barley yield light-
colored yolks.marigold petals may be added to light-colored
feeds to enhance yolk color.
 diphenyl-p-phenylenediamine an antioxidant also showed an
improve in yolk color (Farhad Ahmadi and Fariba Rahimi, 2011)
 CAROPHYLL- commercial product from DSM.

17. Mottling of yolk: vitelline membrane should be intact and
strong prevent the mixing of yolk and albumen. When vitelline
membrane is disintegrated yolk leaks into albumen which results
in translucent areas to brownish colored spots on yolks.
o yolk mottling decreases consumer acceptance, eventhough
mottling has not been shown to affect the egg's nutritional
value or flavor.
o Causes of mottling: Nicarbazin above 0.005%
Piperazine,
Se def,
Gossypol above 0.005%,
high tannins.

18. Egg size: the most imp nutritional factors known to affect egg
size are protein, amino acid (Methionine) adequacy of a diet and
linoleic acid.
• Reduced egg size is observed with marginal protein or amino
acid deficiency.
• Early sexual maturity will produce small sized eggs.
• Egg size increased in birds with delayed sexual maturity.
producers delays maturity by feeding low energy or low
protein or amino acid def. feeds to get the more egg size.

19. Length of storage & storage conditions: as egg gets older, the
dense albumen becomes liquid due to numerous chemical
reactions .
H2 CO3 → H2 O + Co2
o CO2 diffuses through the shell pores and evaporates, decreasing
albumen acidity, increasing pH and chemical cleavage of the
protein complex results in thin & transparent albumen.
o Ideal storage conditions less than 16oc with 80% RH.
o Yolk pH & air cell also increases as storage length increases.
o Rate of Co2 diffusion depends on the temperature and humidity
conditions.
Corrective measures: 3 times egg collection, oiling the egg
surface, preserve below 16oc.

20. Hen strain and age: Egg size is increased with increasing age of
the hen and the yolk increased more in size than did the shell and
albumen (Silversides and Scott, 2001 )
o Eggs from brown-egg layers will usually show a higher
incidence of blood and meat spots than those from white-egg
strains (Jacqueline et al.2000)
Induced moulting: Induced moulting has been shown to
improve the albumen quality of subsequent eggs.
Ingestion of contaminants: Watery egg whites have been
shown to be caused by high levels of vanadium in the feed. High
levels of vanadium can come from certain sources of inorganic
phosphorus (Romoser et al., 1960).
Ex: certain Rock phosphate sources

21. Diseases: The main disease associated with decreased Albumen
quality in layer hens is infectious bronchitis which causes watery
like albumen, it is due to the virus impairs the synthesis of protein
and disintegrates the epithelium of magnum in oviduct of hen.
Ex: Newcastle disease, infectious bronchitis, ILT or Egg
Drop Syndrome 76 (Jacqueline et al.2000)

22. Condition Cause Corrective measure
Olive green yolk Cotton seed in diets Avoid use cotton seed cake
Use iron salts at 4:1 ratio
Colorless yolks Lack of xanthophylls Supplementation of Yellow
corn, marrygold petals,
alfalfa meal
Rubbery or cheesy like Use of crude cotton seed oil,
Freezing and chilling
Avoid cotton seed oil in layer
diets
Off-flavors Storage along with other
chemicals, kerosene,
vegetables and fruits
Store separately
Oiling or packing
Yellow to deep orange Dehydrated alfalfa meal,
corn gluten meal, dried sweet
potatoes, dried carrots, corn-
oilproducts
Feed correct amounts of
carotenoids
Blood spot Deficiency of vitamin K or
vitamin A
Supplementation of Vit A &
K.
Egg yolk defects

23. Condition Cause Corrective measure
Pink egg whites Cottonseed meal
(gossypol,
Sterculic acid,
malvalic acid)
Gossypol free cotton
seed should be fed to
layers.
Greenish albumen Riboflavin Available in the feed.
Weak, thin or watery
whites
Arsenic,
sulfonamides
Do not use arsenic
treated grains in the
diet of layers.
Vanadium Toxic dose should be
avoided.
Blood and meat spots Hemorrhage before
and during ovulation.
Vitamins A and K, and
aureomycin

24. Thank you