Using a tissue culture procedure, scientist at the
USDA in Athens, Georgia, USA, have concluded that moulting may affect the
invasion of tissues by Salmonella enteris
(SE) in laying hens.
They conducted three identical trials in which
80-week-old, active laying hens were divided into two groups of 6 birds each.
The moulted group was subjected to a 14-day period of feed withdrawal, and the
fully-fed group was offered a standard layer ration. After feed treatment, the
crop, ileum, caecum and ovary were collected and subjected to a series of
treatment to prepare them for incubation with salmonella enteritis. This was followed by the removal ob bacteria
that had not penetrated the tissues, and the counting of salmonella enteritis that remained in the tissues.
Salmonella
enteritis
invasion of the ovaries was reduced in tissues from moulted hens in trials 1
and 2 compared with full-fed control (>1.2 log reduction) but not in trial 3.
Salmonella invasion oh the caeca of moulted hens was numerically increased in
trials 1 and 2 and significantly increased in trial 3 compared to the controls
(>0.8 log increase). No significant differences in salmonella enteritis invasion were detected for crops and ileum.
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