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What is the term for an animal that requires large amounts of parental care after birth?
Altricial
What is the term for an animal that requires little parental care after birth?
Precocial
Do altricial birds have eggs with less or more yolk content than precocial eggs?
Hint: do they need less or more energy for developement?
Less
Do altricial birds have eggs with less or more albumen than precocial eggs?
Hint: do altricial birds need more or less protection in the egg?
More
What is the technical term for egg whites?
Albumen
What % of the total egg do the shell and shell membranes comprise?
11%
What % of the total egg does the yolk comprise?
31%
What % of the total egg does albumen comprise?
58%
What is another name for the spongy layer?
Calcareous layer
What are the five components of a shell?
Cuticle
Spongy layer
Mammillary layer
Shell membranes
Pores
What are the four functions of a shell?
Strength
Permit gaseous exchange (pores)
Prevent loss of egg contents and entrance of bacteria (cuticle)
Nutrient source (mainly minerals)
What is the geometric design of a shell?
Crosshatching
What is the thickness of a shell correlated with?
Weight of bird
What is a shell mainly composed of?
Calcium carbonate (calcite)
What are the tough mats of protein fibers that give structure to eggs?
Shell membranes
What forms when the inner and outer membranes of a shell separate at the blunt end?
Air cell
How does an air cell form?
As the egg cools, liquids contract
Where is an air cell located?
Blunt end of egg, between inner and outer shell membranes
What structure supplies air to the embryo when respiration is initiated?
Air cell
What are the three functions of albumen?
Insulation
Shock absorption
Nutrient source
Which layer makes up the highest % of albumen (57%)?
Firm/dense
Which layer makes up 23% of albumen?
Outer thin
Which layer makes up 17% of albumen?
Hint: the number 17 kind of looks like the initials of the answer
Inner thin
Which layer makes up 3% of albumen?
Chalaziferous (thick white)
Which layer of albumen stabilizes the position of the yolk in the egg?
Chalazae
Which albumen layer extends into the firm/dense albumen?
Chalazae
Which part of the egg houses the living center?
Yolk
What is the function of the yolk?
Provides nutrients for embyro
Is a blastodisc present on a fertilized or unfertilized egg?
Unfertilized
What shape is a blastodisc?
Circular
What is the size of a blastodisc?
3-4 mm
Is a blastoderm present on a fertilized or unfertilized egg?
Fertilized
What shape is a blastoderm?
Oval
What is the tubelike structure in the middle of an egg yolk?
Latebra
How does an egg yolk form?
Layers of nutrients deposit on the outside of latebra
What is the name of the membrane that surrounds the yolk?
Vitelline membrane
Which layer of the albumen is highlighted in pink?
Firm/dense
Which layer of the albumen is highlighted in blue?
Outer thin
Which part of the egg is highlighted in green?
Latebra
Which part of the egg is highlighted in yellow?
Blastoderm
Which part of the egg is represented by the black and white swirls?
Yolk
Which part of the egg is represented by the gray whispies on either side of the yolk?
Chalazae
Which part of the egg is represented by the gray highlighting surrounding the yolk?
Inner thin
What egg defect forms when vessels rupture in the yolk follicle at the time of ovulation?
Blood spot
What egg defect forms when two yolks meet in the oviduct and are included in the same shell?
Double yolk
What is the most common egg defect?
Double yolk
What do the germicidal properties of eggs do?
Help kill/prevent the growth of bacteria
What are the four germicidal properties of eggs?
Shell
Shell membranes
Avidin
Lysozyme
What is the first line of defense for an egg?
Shell
What compound does a shell contain that acts as a drying agent?
Calcium carbonate
How do shell membranes act as germicides?
Act as filters (pores are smaller than those in shell)
Which germicidal enzyme in the albumen interferes with bacterial growth?
Avidin
Which germicidal enzyme in the albumen dissolves/lyses bacteria and is also found in tears?
Lysozyme
Egg contents are what % water?
74%
Egg contents are what % dry matter?
26%
Egg contents are what % proteins?
13%
Egg contents are what % fats (same as shell)?
11%
Egg contents are what % carbohydrates?
1%
Egg contents are what % minerals?
1%
Egg yolks are what % dry matter?
52%
Egg yolks are what % fat?
33%
Albumen is what % water?
88%
Albumen is what % protein?
10%
Egg shells and membranes are what % minerals?
92%
What are causes for variations in egg composition?
Type and strain of bird
Day-to-day variation
Weather/climate
Nutrition
Disease status
What are the nine egg minerals?
Ca, Cl, Fe, Mg, S, K, P, Na, I
Which egg minerals are found mainly in the shell?
Ca, Mg, P
What are the four egg proteins found in the albumen?
Ovalbumin
Ovoconalbumin
Ovoglobulin
Ovomucin
What are the two egg proteins found in the yolk?
Ovovitellin
Ovolivetin
What is the one egg protein found in the membranes?
Ovokeratin
Which egg protein makes up 75% of albumen?
Ovalbumin
What is the nutritional quality of egg proteins?
Very high → nature’s best proteins
Where are most egg lipids located?
Yolk
What are the four lipids present in eggs?
Triglycerides
Phospholipids
Sterols (cholesterol)
Cerebrosides
What % of egg lipids do triglycerides comprise?
62%
What % of egg lipids do phospholipids comprise?
33%
What % of egg lipids do sterols comprise?
5%
What % of egg lipids do cerebrosides comprise?
Trace
What % of fatty acids in eggs are saturated (opposite of milk)?
34%
What % of fatty acids in eggs are unsaturated (opposite of milk)?
66%
Where are most of the carbohydrates in eggs located?
Albumen
Are there lots of carbohydrates in eggs? What is their purpose?
No → only purpose is to provide sugar for embryo
Eggs are a good source of vitamins except for which?
Vitamin C
What are the two enzymes present in eggs?
Avidin and lysozyme
From a consumer viewpoint, what makes an egg good quality?
Intact and clean shell
No blood spots
No off-flavors
Uniform size, shape, and color
Uniform yolk color
Large amount of firm albumen
What are the three internal factors that influence egg quality?
Genetics
Physiology
Nutrition
What are the three external factors that influence egg quality?
Temperature
Humidity
Contamination
When is an egg’s quality highest?
Immediately after it is layed by the hen
What is shrinkage?
Loss of water when stored in low humidity
What happens to the air cell during shrinkage?
Enlarges
During liquefaction, which gas is lost from the albumen?
CO2
During liquefaction, due to CO2 loss, what happens to the amount of water the albumen binds?
Decreases
During liquefaction, due to water released from albumen, what happens to the size of the yolk?
Enlarges → runnier
How can liquefaction of eggs be reduced?
Pump CO2 into the atmosphere
Liquefaction is directly related to which factor of proper egg storage?
Temperature
What is the temperature storage requirement for eggs?
45-55°F
What is the humidity requirement for eggs?
>80%
Storing eggs at a low temperature prevents what?
Liquefaction
Storing eggs at a high humidity prevents what?
Shrinkage
What are the three egg grades?
AA
A
B
Note
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