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Blood
Avian Physiology
Function of Blood - Transport
• Oxygen,
• CO2
• Nutrients - glucose, amino-acids, lipids,
lactate
• Water
• Waste - uric acid/urates
• Heat – body temperature
• Hormones
• Immune protection
• Osmotic balance/ minerals
Components of blood
• Plasma
– 60-70% of blood
• Cells/corpuscles
– 30-40% of blood
– Hematocrit = 30-50
Hematocrit
• Hematocrit = Packed Cell Volume (PCV) after
centrifugation of whole blood
Components of Plasma
• 90% water
• 10% solutes
– Minerals - Na, K, Ca, Mg, HCO3, Cl, Phosphate
– Nitrogenous Compounds:
• Proteins – 3-6 g/dl
• non-protein nitrogen (uric acid, urate)
– Nutrients - glucose 150-250 mg/dl (fasting)
– Lipids - free fatty acids, neutral fats,
phospholipids, cholesterol esters
– Yolk precursors + Hormones
Centrifuge blood with an anticoagulant
(prevents clotting) to separate plasma
from cells.
Prior to
After
Centrifugation Centrifugation
Plasma
Buffy coat = WBC
Red Blood Cells
Corpuscles
Plasma proteins
• Albumins –greatest, 40% of total plasma protein
– Transport other substances (hormones)
– Osmolality of blood and Egg formation
• Clotting proteins= fibrinogen, pro-thrombin
• Globulins
– α and β globulins are transporters
– γ globulins are antibodies
• Hormones
• Lipoproteins, i.e. yolk proteins
• Glycoproteins
• Hemoglobin
• Enzymes
Clotting Proteins and Clotting
• Clotting should not occur unless injury
• Initiated by Prothrombin activating factors, ie
Thromboplastin
• Factors that cause release of thromboplastin:
– Extrinsic Factors = external trauma that damages
vessels
– Intrinsic Factors = damage of blood cells
• Fast uncontrolled once started
Clotting Proteins and Clotting
• Cascade:
 Prothrombin activating factors
Prothrombin  Thrombin
(an α globulin)

Fibrinogen   Fibrin threads
+ Ca++
+ fibrin stabilizing factor =
Polymerization and clotting
Clotting Time
• Whole chicken blood clots in 2 – 120 min.
• Prothrombin time is more sensitive:
– Add Ca chelator – sodium citrate or Ca
precipitator – sodium oxalate (anticoagulants) to
prevent blood from clotting prior to test.
– Separate cells from plasma by centrifugation
– Add excess of Ca and known amount of
prothrombin to plasma
– Record time required for clot formation.
Prothrombin Time
• Chicken prothrombin time is 10-20 sec with 12 sec
average.
• Vit. K is needed for synthesis of many
procoagulation factors
– ↓Vit. K in diet and blood = ↑Prothrombin time
– Prothrombin time is an accepted bioassay for Vit.
K levels in chickens.
What prevents blood from clotting in
the circulatory system, since
everything is in there that is needed
for clotting?
• Natural anticoagulants = heparin
• Roughed surface is needed for clot formation
• No injured vessel then intravascular clotting is
rare.