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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 = dead•enteritis= 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
Performanceto 6 weeks
Effect ofremoval
Range
Liveweight - 50 grams 0 to 150 gms
FCR +0.04 0 to 0.08
Mortality +0.1% -1.3% to 1.0%
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