Clinical Biochemistry of Domestic Animals (Sixth Edition) - UMK ...

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Chapter | 5 Proteins, Proteomics, and the Dysproteinemias
Albumin
α 1
α 2
β
PRE
all species. Growth hormone is another well-known anabolic
hormone with similar effects. On the other hand, thyroxine
decreases total serum protein, most likely because of its
catabolic effect. The glucocorticoids have not been reported
to have a major effect on SPE except in the dog where
prednisolone injection was shown to cause an increase in
α 2 -globlins with the rise shown to be due to the induction of
haptoglobin ( Harvey and West, 1987 ). Otherwise hormonal
effects of serum proteins are slight even though their effects
on weight gains or body composition may be quite marked.
Albumin
the absorption of immunoglobulins. Baby pigs acquired
large amounts of γ -globulin, which progressively decreased
to 5% of the total serum protein by 4 weeks of age ( Rutqvist,
1958 ). In the calf, precolostral serum normally contains no
γ -globulin, but within a few hours after ingestion of colostrum,
γ -globulin appears in serum (see Fig. 5-8 ) and absorption
continues for up to 36 hours after birth after which closure
occurs ( Weaver et al. , 2000 ). In colostrum-deprived calves,
immunoglobulins increase only minimally. In the developing
foal from birth to 12 months of age, progressive increases in
albumin, globulins, and total proteins are also seen ( Bauer
et al. , 1984 ; Rumbaugh and Adamson, 1983 ).
Over the life span of animals, there is a general increase
in total protein, a decrease in albumin, and an increase in
globulins with advancing age. However, in the very old, the
total plasma proteins again decline. Thus, age is an important
consideration in the interpretation of the SPE. Breed
may also affect serum proteins. Retired greyhounds were
found to have significantly decreased α - and β -globulins
in comparison to age- and gender-matched nongreyhound
controls ( Fayos et al. , 2005 ).
2 . Hormonal and Sexual Infl uences
POST
α 1
α 2
β γ
FIGURE 5-8 Densitometer trace of serum protein electrophoresis on
agarose gel from calf before feeding with colostrum ( upper ) and after
feeding with colostrums ( lower ).
Hormones can have anabolic or catabolic effects on serum
proteins. Testosterone and estrogens are generally anabolic in
γ
3 . Pregnancy and Lactation
During gestation, maternal albumin decrease and the globulins
increase in some species . In ewes, albumin decreases
to a minimum at midgestation and returns to near normal
at term, whereas globulins and the total serum protein
progressively decrease throughout gestation ( Dunlap and
Dickson, 1955 ). In cows, the total serum protein and γ 1 -,
and β 2 -globulins begin to increase at 2 months before term,
reach maximum values at 1 month, and then rapidly decline
toward term ( Larson and Kendall, 1957 ). This reflects the
transport of immunoglobulins from serum to the mammary
gland that begins several weeks before parturition, reaching
a peak 1 to 3 days before birth of the calf ( Weaver et al. ,
2000 ). Lactation and egg production impose further stresses
on protein reserves, and metabolism and changes similar to
pregnancy may also occur. However, no changes in serum
albumin or total globulin concentrations were measured in
horses during gestation or lactation ( Harvey et al. , 2005 ).
4 . Nutritional Infl uences
The plasma proteins are sensitive to nutritional influences,
but the changes are often subtle and difficult to detect and
interpret. In a study in Holstein heifers, increasing the
proportion of crude protein in the diet from 8% to 15%
increased total serum protein and albumin, but the albumin:
globulin ratio stayed the same at 1.09 ( Hoffman et al. , 2001 ).
Increases in α -globulin and decreases in γ-globulin fractions
were found in ostriches fed a high-protein diet ( Polat et al. ,
2004 ). In contrast, total serum protein was not affected in
pregnant mares by substantial differences in dietary protein
quantity and quality, even though the foal mass decreased by
25% ( vanNiekerk and vanNiekerk, 1997 ).
5 . Stress and Fluid Loss
Temperature stress, either fever or hypothermia, is associated
with nitrogen loss, increased adrenal activity, and
increased protein turnover. These stresses cause a decrease
in total serum protein and albumin, but they often cause
an increase in α 2 -globulin associated with the acute phase
response. Similar findings are observed in crushing injuries,
bone fractures, and extensive surgery. In the inflammatory