Lead Toxicity in Mute Swans

I
the haematocrit values (Table 1). Adults had smaller reference ranges
than immatures (Table 1).
Reference limits for the other blood parameters based on a sample
of about 100 Mute swans are shown in Table 2.
While the range for most
parameters is small, the range for urates is large (Table 2).
Two
reference ranges are given for protoporphyrin IX, uncorrected values
and values related to haemoglobin content.
Blood chemistry values for caged swans are shown in Table 3.
There
was little change in the levels of blood parameters studied throughout
the period (16.30 -
07.00hrs), except in the case of three compounds.
The concentration of urate was variable between individuals but all
values dropped from the initial time of caging.
In contrast, the
levels of cholesterol increased from the time of caging until after
release, with one bird twice exceeding the upper reference limit (Table
3). In almost all cases, sodium exceeded the upper reference range
throughout the period of night sampling.
Protoporphyrin IX and haemoglobin showed values outside the
reference distribution in some apparently healthy birds, though the
values were within the maximum/minimum limit (Table 2).
Some cygnets
(immatures less than four months old) had high levels of circulating
Protoporphyrin IX (Table 4).
Haemoglobin, paematocrit and mean cell
haemoglobin values for eight Mute swans with apparent anaemia are given
in Table 5.
All values were outside the reference distribution, though
they approached and equalled the minimum values recorded (Table 1).
Mean cell haemoglobin concentration values were low in all the females
(Table 5), indicating hypochromic anaemia.
Haematocrit values in
moulting birds, however, were variable (Table 5).
These birds were at
an advanced stage of plumage replacement, following primary moult.
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