Download Review of cholangiohepatitis: gross pathology, histopathology and

Review of cholangiohepatitis:
gross pathology, histopathology
and pathophysiology - the whats
and the whys!
Stephen Lister
Crowshall Veterinary Services
Big livers - big words!
• Necrotic enteritis (NE)
• Clostridium perfringens
(CP)
• Cholangiohepatitis (CH)
Necrotic enteritis
• First described in 1961 in
England
• reproduced by infecting chickens
with clostridia
• was a significant clinical disease
• “disappeared”
• now re-emerging as the disease of
the moment
Necrotic enteritis
• Necrotic
• enteritis
=
=
dead
inflamed
intestine
The intestines
• An important organ
• interface between feed and
ability to transform this into
£.s.d
• works best in a state of
homeostasis
Homeostasis
• Homeo = same
• stasis = state
• i.e. keeping everything
in balance
The intestines
• Chick hatches with a sterile
gut
• gut is receptive to
colonisation with bacteria
• development of a balanced
gut microflora
• numerous bacteria
Gut bacteria
•
•
•
•
•
•
•
•
clostridia
E coli
streptococci
staphylococci
proteus
pseudomonas
lactobacillus
enterococcus
•
•
•
•
•
•
•
•
citrobacter
eubacterium
veillonella
fusobacterium
bacteroides
propionobacteria
bifidobacteria
etc etc
Necrotic enteritis
• A consequence of the loss of this balance
• Enterotoxaemia of chickens caused by
toxigenic strains of Clostridium perfringens
types A
• reproduced by infecting chickens with
clostridia
• mostly affecting broilers,
• but also turkeys, occ. layer and breeder
replacements, ducks, geese
But why?
• Models for creating necrotic
enteritis - how to do it!
•
•
•
•
•
feed clostridia
feed contaminated with clostridia
change gut pH + clostridia
coccidial challenge + clostridia
high wheat + coccidia + clostridia
But why?
• Clostridial proliferation
• damage to the gut
• changes in the gut
• loss of homeostasis
Effects
• Mortality
• loss of performance
Loss of performance
Performance Effect of
to 6 weeks
removal
Liveweight
- 50 grams
Range
FCR
+0.04
0 to 0.08
Mortality
+0.1%
-1.3% to
1.0%
0 to 150 gms
Ross Breeders trials looking at effect of removing Maxus from the diet 1999
Effects
• Mortality
• loss of performance
• diarrhoea
• wet litter
• need to treat
• and …..
….. if that’s not enough!
• Carcase rejects and bad colour
• liver damage and jaundice
• cholangiohepatitis (CH)
What is it?
• cholangiohepatitis or fibrosing
cholehepatitis or
septic intrahepatic choleostasis
• hepatitis = liver inflammation
• septic = infection
• intrahepatic = in the liver
• choleostasis = bile stops
Findings on the processing line
•
•
•
•
•
•
•
Bad colour
jaundice
ascites?
Enlarged liver
tan coloured
knobbly appearance
speckled liver
What is happening?
• It is costing money through
downgrading
• 3 to 5% downgrades not unusual
• We know there is an association with
NE & CP
• often no disease reported on farm
• so why do I see CH without seeing NE
or any significant increase in
mortality?
Experimental work
• Not a lot of published literature
• Onderka et al (1990) in Canada
• Experimental reproduction of the
problem
– ligating the bile ducts
– injecting CP into the bile duct
Ligating bile ducts
• 21 to 28 days of age
• 6 days p.l.: intensely yellow
droppings
• 5 days p.l.: bile duct proliferation
• 10 to 14 days p.l.: liver changes
• 28 days p.l.: enlarged tan
coloured liver, speckled
appearance
Injecting CP
• 5 to 7 days p.i.: swollen
mottled livers
• 12 days p.i.: pale, firm
mottled livers
• 17 days p.i.: enlarged, firm,
tan coloured, speckled liver
What is happening?
• Clinical or subclinical NE can lead to
CH at processing
• clostridial infection of liver/bile ducts
can be “silent”, or associated with
very small lifts in mortality but still
lead to considerable downgrading
• timing of clostridial proliferation is
not precisely known, but can be <10
days of age
But why?
• Clostridial proliferation
• damage to the gut
• changes in the gut
• loss of homeostasis
But what has changed?
•
•
•
•
•
•
•
cereal content
cereal type
use of barley
use of whole wheat
loss of GPs
loss of MBM
changes in raw
materials
• least cost rations
• shorter turnaround
times
•
•
•
•
•
•
•
Lighting programmes
Less routine antibiotics
coccidiostat choice
chemical shuttles
longer withdrawl times
gumboro disease
Chick anaemia virus