Lead Toxicity in Mute Swans

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oesophagus, proventriculus and gizzard were impacted with food
( 150 gms consisting mostly of grass and a small quantity of bread).
The horny epithelium of the gizzard was yellow in colour and broken
away from the basement membrane. Four split shot lead weights
were found in the gizzard. By comparison with those of the nonpoisoned
cygnet, the remaining internal organs appeared normal.
However, in the lead poisoned bird the weight of the heart and
gizzard were noticeably lighter (Table 5).
(b) The Cygnet
The cygnet had suffered severe fractures and many of the tissues
were damaged due to the accident. The weight of the bird was normal
for a bird of its age (Table 1). The pectoral muscle was normal, and
the oesophagus, proventriculus and gizzard showed no sign of being
impacted. The gizzard contained no lead weights, its weight and that
of the heart were heavier than those of the poisoned bird (Table 5).
Histological Results
Plate 72 reveals a large intra-nuclear inclusion body within the
nucleus of a proximal tubule cell from the kidney of the poisoned
swan. Electron microscope examination revealed that these inclusion
bodies were present throughout the kidney tissue. The inclusion bodies
were not only found in the nucleus but were also found in the
mitochondria and cytoplasm. These bodies were not confined to the
Plate 7 J. Abnormal carnage of neck of lea d po i sone d M; u te Swan at Cork cityPhoto:
J. H. Daly
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