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