PoultryUSA - August 2018 - 48
48 ❙ WATTPoultryUSA
infection routes in broilers
The pathogenic bacteria can spread through a number of bodily
routes and infect a large portion of the flock if unchecked.
NELSON COX, ET AL.
Newly hatched broiler chicks can
be exposed to significant levels of
Salmonella and Campylobacter
in the hatching cabinet, the
hatchery and the broiler house.
Exposure of chicks to Salmonella
and Campylobacter is critical
because the bird lacks a mature
gut microflora and is highly susceptible to colonization by the
Microbes can enter chicks
through an assortment of body
openings: the mouth, nares, cloaca, eye and navel. Once bacteria
reach the ceca, they may colonize
and multiply exponentially in a
short time. At this point, the animal can become a seeder chick
by excreting the bacteria in its cecal droppings and contaminating
other birds in the broiler house.
Studying infection routes
These studies evaluated vari-
Inoculation of a day-old chick by oral gavage.
US National Poultry Research Center
ous possible routes of Salmonella
or Campylobacter entry and
looked to determine which would
produce appreciable numbers in
the ceca. In order to avoid confounding by natural contaminants,
strains of bacteria, a nalidixic
SALMONELLA AND CAMPYLOBACTER
CAN contact and colonize the chick
intestinal tract through an assortment
of body openings.
acid-resistant S. Typhimurium
(ST) and a gentamicin-resistant C.
coli (Cc), were used.
Varying numbers of each organism were introduced to chicks by
mouth, cloaca or dripping in the
eye. Exposed chicks were housed in
isolation units on wire mesh. Seven
days post inoculation, all chicks were
humanely euthanized by cervical
dislocation, surface disinfected with
70 percent ethanol and ceca aseptically removed and analyzed for the
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