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

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Chapter | 28 Avian Clinical Biochemistry
Bile acid (µmol/l)
80
60
40
20
FIGURE 28-17 Plasma bile acid concentrations
(mean SD) in peregrine falcons, Falco peregrinus
(n 6) after a 42-h fasting period and 3, 8, 15, and 24 h
after birds were fed a complete skinned quail, Coturnix
coturnix, at 0 h. Values at 3, 8, and 15 h are significantly
different from values at 0 and 24 h ( p 0.05). Reprinted
with permission from Lumeij and Remple (1992 ).
0
0 5 10 15 20 25
Time (hr)
( Gracula religiosa ) and toucans ( Rhamphastos spp.). In these
species, hemochromatosis is often associated with hepatic
fibrosis, but the causal relation has not been confirmed.
Hemosiderosis should be considered in the differential
diagnosis of avian hepatopathy. Diagnostically, determination
of blood iron concentrations is not reliable. There is,
however, a positive correlation between the concentration
of stainable iron determined by image analysis of histological
sections and biochemically determined liver iron concentration.
For a review, see Cork (2000) .
K . Clinical Diagnosis of Liver Disease
The index of suspicion of liver disease can be raised by the
use of physical examination, plasma chemistry (enzymes,
BA, TP, and PPE, galactose clearance test, and ultrasonography).
However, to make a specific diagnosis, liver biopsy
is the only method currently available (Lumeij, 1994a).
VII . MUSCLE DISEASE
Muscle enzyme profiles, half-lives of these enzymes in
plasma, and plasma chemistry changes after experimentally
induced muscle damage have been reported for racing
pigeons (see Section VI.B). Enzyme profiles were
studied for pectoral muscle, quadriceps muscle, and heart
in pigeons and parrots ( Fig. 28-13 ). Creatine kinase (CK)
was the most important enzyme in these three muscles,
followed by LDH, AST, and ALT. Muscle damage was
induced by injection of doxycycline in the pectoral muscle
in pigeons ( Fig. 28-16 ). Creatine kinase activity in plasma
was markedly elevated (about 20-fold) 16 h after injection.
However, within 66h plasma activities of CK had returned
to the maximum value of the reference range. LD activities
were only slightly elevated (about twofold) and only
for about 40 h. AST activities showed a marked increase
(about fourfold) for about 140 h, whereas ALT showed a
marked increase (about fivefold) for about 214 h. Despite
the fact that ALT activities in individual muscles are low,
elevated plasma activities of this enzyme can be seen until
9 days after muscle damage. Plasma CK activities, on the
other hand, return to within the reference range within 3
days after muscle damage, despite high tissue activities.
LDH appeared to be a relatively poor indicator of muscle
cell damage, despite relatively high activity of this enzyme
in muscle ( Fig. 28-16 ). These findings can be explained by
the differences in elimination half-lives of the respective
enzymes (LDH 50 min, CK 3h, AST 7h, ALT 12 h; Tables
28-1 and 28-2 ).
Not all elevated concentrations of muscle enzymes in
plasma are an indication for muscle disease. Extreme muscular
activity in the period preceding blood sampling is an
important cause of elevated enzyme activities in plasma. In
dogs, plasma CK activities increase approximately twofold
with exercise ( Heffron et al ., 1976 ). Trained persons have
plasma CK activities that are twice those of more sedentary
people ( Okinaka et al ., 1964 ). In humans, elevated activities
of plasma CK can persist for about 1 week after exercise
( Newham et al ., 1983 ). Chronic elevated plasma CK
activities have been reported in certain occupational workers
as a result of local muscular strain ( Brewster and De Visser,
1988 ; Hagberg et al ., 1982 ). In healthy turkeys, plasma CK
activity is extremely sensitive to physical exercise and stress.
With controlled conditions of minimal exercise, stress, and
time of handling, however, iatrogenic elevations of plasma
CK activities can be prevented ( Tripp and Schmitz, 1982 ).
Limited handling of penned mallards resulted in mean SD
serum CK activities of 1325 1212 IU/L, whereas capture
of wild mallards in entanglement nets resulted in serum CK
activities of 12035 8125 IU/L, compared to 225 52 IU/L
in control animals with minimal handling (Dabbert and
Powll, 1993). Elevated plasma CK activities can be expected
in birds with large muscle mass after capture stress (e.g.,
ostrich). Intramuscular injections in birds are a well-known