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

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Chapter | 28 Avian Clinical Biochemistry
F. J. Archer & A. L. Battison
PSITTACOSIS
18.10.85
Total protein 40 g/L
(34-45)
A/G 0.54
(1.5-3.9)
a
b
1 2 3 4 5 6
FIGURE 28-7 Agarose gel electrophoresis. From left to right, chicken
( Gallus gallus domesticus ) serum (lane 1), purified chicken albumin (lane
2), chicken plasma (lane 3), cockatiel ( Nymphicus hollandicus ) plasma
(lane 4), purified cockatiel albumin (lane 5), and cockatiel serum (lane 6).
Chicken albumin (lanes 1, 2, and 3, band b) migrated further than cockatiel
albumin (lanes 4 and 6, band a). Cockatiel albumin migration was
similar to that of chicken α globulins (lanes 1 and 3, band a), whereas
cockatiel prealbumin migration (lanes 4 and 6, broad bands b) was similar
to that of chicken albumin. Purification of cockatiel albumin (lane 5,
single band) altered its migration pattern, whereas purification of chicken
albumin (lane 2, single band b) did not have this effect. Reprinted with
permission from Archer and Battison (1997) .
birds, and their data did not span the full range of clinical
values. Because values of individual globulin fractions
in healthy birds are low and boundaries between the various
globulin fractions are not clear, it is to be expected that
large bias is introduced when an arbitrary (manual) distinction
between the various globulin fractions has to be
made ( Cray, 2005 ; Rosenthal et al. , 2005b ). Their study
did, however, confirm the high reliability of determinations
of TP and Alb, whereas measurement of γ -globulins had
fair to good agreement. Determination of the A/G ratio as
described earlier and visual inspection of the globulin fractions
in case of abnormal values will leave no doubt on the
fractions responsible for the abnormalities, as, for example,
in the hyperglobulinemia reported by De Wit et al . (2003) .
G . Albumin Methodology
The labor-intensive PPE is not available in every laboratory,
and Alb is commonly determined chemically by the bromcresol
green (BCG) dye-binding method. The BCG method
is unreliable in avian blood. Discrepancies between values
obtained by dye-binding techniques and those obtained by
electrophoresis have been demonstrated for chicken, duck,
turkey, and pigeon ( Lumeij et al ., 1990 ; Spano et al ., 1987,
1988 ). In general, Alb determinations performed with dry
methods have not been validated for use in birds.
Furthermore, various Alb standards can be used in different
laboratories, although most commercial laboratories
will use a human standard for TP and Alb determinations.
The method used should have been validated for the species
pre alb
2 12 7 12 7
in question and compared with reference values established
in the same laboratory.
H . Prealbumin
2 21 2 4 7 7
26 2 2 3 2
13.11.85
Total protein 43 g/L
A/G 1.15
18.12.85
Total protein 35 g/L
A/G 2.88
FIGURE 28-8 Plasma protein electrophoresis and the albumin:globulin
ratio (A/G) in an African grey parrot ( Psittacus erithacus erithacus )
with psittacosis, before, during, and after treatment with doxycycline.
Symbols: Pre, prealbumin; alb, albumin; α , β , γ , globulin fractions (reference
values in parentheses). Reprinted with permission from Lumeij
(1987e) .
Prealbumin is the most rapidly migrating fraction in avian
plasma and has been associated with binding thyroxine
and retinol (thyroxine binding prealbumin-TBPA; transthyretin).
Although the protein travels anodal to albumin
in birds, primates, and the horse, it is usually not visualized
in the last. In other species transthyretin travels cathodal
to albumin or has the same motility to albumin, which
explains the absence of a “ prealbumin ” fraction in these
species using routine electrophoresis techniques ( Chang
et al. , 1999 ; Larsson et al. , 1985 ). Seasonally high concentrations
of plasma transthyretin concentrations (150
to 200 mg/L in May through July versus 80 to 100 mg/L
in September through January) have been associated with
molting in storks ( Cookson et al. , 1988 ).