Blood Plasma Protein & Dehydration

• Clinical Biochemistry of Blood is critical due to its other essential functions linked to the blood's biochemical components.

Functions:

• Transports biochemical compounds such as vitamins, hormones, and enzymes from where they are synthesized to various tissues and organs.
• Preserves the balance of acidity and alkalinity (pH) and regulates water and ion balance between intracellular fluid, interstitial fluid, and intercellular fluid.
• Regulates body temperature within a consistent range.
• Protects the body by transporting immune bodies to the site of infection.

Biochemical Composition of Blood:

• The biochemical makeup of blood remains relatively constant in a healthy state.
• It relies on organized systems and mechanisms involving the nervous and endocrine systems, as well as the enzymatic system.
• These systems ensure the stability of blood composition within the physiological range.
• The systems support the interdependence of organ functions, such as the liver, kidneys, lungs, and cardiovascular system.
• Minor changes in blood composition may occur under various physiological, environmental, nutritional, and housing conditions.
• These changes typically self-correct without medical intervention once the influencing factor is eliminated.
• Changes in blood composition during pathological conditions are critical and require prompt treatment.
• Biochemical analyses of bodily fluids, particularly blood, can provide clear insights into bodily disorders.
• Blood contains most biochemical compounds measurable through appropriate laboratory methods.
• Biochemical blood analysis is widely used in veterinary medicine to detect various diseases.

Plasma Proteins

• Plasma proteins constitute most of the dry matter in blood plasma, ranging from 6.5% to 8.5%.
• The remaining dry matter consists of other organic and inorganic compounds.
• Total protein concentration in plasma is approximately 60-80 g/L in domestic animals, except for dogs, which have a slightly lower range (53-73 g/L).
• Total protein comprises over 100 protein compounds.
• For ease of study, they are categorized into three main groups: Albumin, Globulins, Fibrinogen.

Alterations in Total Plasma Protein Concentration:

Hyperproteinaemia (Increased Total Protein Concentration in Plasma):

• Several primary factors include Relative water deficiency
• Relative water deficiency occurs in high-producing dairy cows with severe dehydration and chronic anemia accompanied by dehydration.
• PCV (packed cell volume) remains within normal limits or slightly below normal, masking dehydration unless total plasma protein concentration is assessed.
• An increased total protein concentration may be associated with an elevated red blood cell count due to splenic contraction caused by adrenaline release, leading to a 20-25% increase in PCV within minutes.
• Measuring plasma protein concentration is theoretically less valuable in diagnosing dehydration than PCV because proteins are not exclusively found in the blood.

Hypoproteinaemia

Decreased total plasma protein concentration

• General protein synthesis deficiency in the body that occurs in newborns of all species.
• Malnutrition - Protein or nitrogen deficiency reduces albumin levels in the blood and can result from emaciation and poor appetite.
• Factors include impaired digestion, reduced intestinal absorption, liver damage, advanced pregnancy and lactation.
• During the first half of pregnancy in sheep, albumin levels decrease, while globulin levels decrease after birth due to increased excretion with colostrum.

Protein Loss in the Body:

• Significant blood loss, particularly in horses.
• Chronic blood or protein loss, as seen in chronic enteric diseases and parasitic infections.
• Kidney diseases, especially nephrosis and tubulointerstitial nephritis.
• Exudative burns, particularly those covering 40-50% of the skin surface.
• Plasma protein loss into body cavities caused by ascites, internal bleeding, exudative pleurisy, or exudative pericarditis.

Changes Affecting Protein Fraction Concentration:

Albumin Deficiency:

• Occurs due to inhibited synthesis in the body, resulting from malnutrition, maldigestion, liver diseases, protein breakdown, albumin leakage.
• Conditions like edema, ascites, and hydrothorax can result.
• A decrease in albumin is primarily associated with diseases affecting the liver, kidneys, and intestines.
• Tests assessing liver function and kidney function are used to evaluate these organs.
• Intestinal function is assessed by observing chronic diarrhea and identifying malabsorption.

Increased Globulin Concentration in Plasma:

• Alpha Globulins: Elevated in inflammatory conditions, especially in dogs, and in acute and chronic kidney diseases, tissue breakdown, tumors, and fever.
• Beta Globulins: Elevated in liver diseases, disorders of fat metabolism, diabetes mellitus, hypothyroidism, acute internal parasitic infections in horses, chronic skin diseases in dogs, and eosinophilic myositis.
• Gamma Globulins: Increased concentration reflects the response of the reticuloendothelial system (R.E.S) to antigens.
• The increase during infectious diseases depends on the severity of the disease and the host's response.
• Gamma globulin concentration in horses is very low at birth but rapidly increases in newborns after ingesting colostrum.
• Levels change with bacterial, fungal, and parasitic infections but may not change or increase slightly with viral diseases.

Fibrinogen (Factor I):

• Fibrinogen is present in blood at a low concentration (2-4 g/L) compared to other proteins and occupies an essential role among blood proteins.
• It has properties similar to globulins, dissolves in water, and gives the blood its clotting ability.
• Decreased Fibrinogen levels are caused by consumption of blood samples, liver diseases, complications of childbirth, shock, and nutritional disorders.

Carbohydrates and Lipids

Glucose (Glycogen):

• It is physiologically important in the animal body where it can be found in all cells and tissues. It is found in all cells and tissues.
• Blood sugar remains constant in blood plasma and simple-stomached animals have levels between (4-5.5 mmol/L.) While ruminants have a lower concentration, around (3-4 mmol/L).
• The amount of glucose always stays constant which is massively important physiologically.

Renal Threshold for Glucose:

• The glomeruli permit the glucose to be diffused entirely before it reabsorbs into the renal tubes again.
• Reabsorption has limits, and in occasions where there is an increase in glucose concentration in the blood.
• This is because the reabsorption becomes incomplete due to impaired function, and can appear with urine.
• Increased concentrations such as this are called Glycosuria.

Changes affecting glucose concentration in the blood:

• An increase in blood glucose concentration occurs after eating sugary foods, difficult breeding, under stress, with steroidal treatment, with sugar solutions, and with diabetes.

A decrease can be caused by:

• Insulin concentration.
• Pancreatic damage by tumors, and starvation.
• As well kidney, metabolic disorder such as ketosis, liver failure, hypoglycemia due to food deficiency, hypoglycemia (spontaneous).

Ketone Bodies (Acetone):

• Byproducts produced during metabolism of the body.
• Normally found in ruminants and created in liver tissue with low concentrations in mammary glands.
• Concentration is increased in cases of ketosis, pregnancy toxemia, fatty liver, diabetes, or hypoglycemia.
• Or certain digestive and dietary conditions such as inflammation and acidosis.

Understand blood plasma composition, focusing on protein content and its significance. Testing for total plasma protein concentration is important during dehydration, which can increase protein levels. Assessing protein concentration is useful in various conditions.