Industry Focus

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Industry Focus

• Clostridial Enteritis

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Vision without action is a daydream. Action
without a vision is a nightmare. - old
Japanese proverb
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Improvement in Performance
42 days old chicken in 1957 508 g in 1991
2200 g
At least 80 of this improvement was down to the
contribution of genetics!
Source Poultry International Sept 1998
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Clostridial Enteritis - a syndrome emerging
worldwide

• Intestinal health and perfect droppings are the
  joy of the poultry manager.
• Flocks that grow without problems are rare indeed.

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Syndromes associated with bacterial overgrowth

• Necrotic Enteritis - Clostridia
• Cholangiohepatitis - Clostridia
• Dysbacteriosis - other bacteria

Early stages Clostridial enteritis Later phase
Necrotic enteritis
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Intestinal bacterial overgrowth responsive to
antibiotics
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Necrotic Enteritis

• Well understood disease
• Caused by Clostridium perfringens typ A.
• The organisms replicates readily in the
  intestinal tract.
• Produces alpha toxins -gt mucosal necrosis

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Etiology

• The chick is born with a sterile intestinal
  tract.
• For the first two weeks the oxygen content of the
  intestinal flora prevents the multiplication of
  clostridia (anaerobic).
• After two weeks clostridia begin to proliferate
  and clinical disease results.
• Focal ulceration in duodenum and jejunum.
• In subclinical form does not result in mortality
  but is associated with poor performance.

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Predisposing factors

• Management
• - stress
• - poor hygiene/sanitation
• - crowding
• - wet litter
• Dietary factors
• - high fiber diets /barely, oats, rye/
• - viscosity of the gut
• - oxidized fats and mycotoxins
• - long withdrawal periods (anticoccidials, GP's)
• - feed and litter contaminated with clostridial
  spores.
• Immune suppression - IBD - Aflatoxins
• - Marek's - CAV
• - virulent adenovirus (serotype 8)
• Concurrent disease - Coccidiosis (scores gt2.8)
• - Parasitic worm infections
• - Bacterial infections

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Controlling NE
Eliminating predisposing factors

• Management
• - clean and disinfect buildings, proper
  turn-around time
• - avoid overcrowding
• - maintain dry litter
• - ensure proper ventilation
• Dietary factors
• - evaluate nutritional and fiber content of feed
• - avoid long withdrawal periods
• - use digestive enhancers
• - enzymes to offset viscosity
• Immune suppression
• - reduce immunosupressive stress and diseases
• Concurrent diseases
• - Coccidiosis control with coccidiostats using
  stable programs and ionophores vs. chemicals

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Controlling necrotic enteritis

• Ionophores have a high anticlostridial activity,
  narasin reported especially active.
• Create stability and immune stimulation
• Max. 2-3 programs/year
• NE can be a real issue, when chemicals
  (Diclazuril, robenidine, DOT etc.) or vaccines
  are used.
• Therapeutic programs
• Competitive exclusion
• Vaccination against NE
• successful in ostriches
• current vaccines are killed type, need to be
  injected
• A program of two injections is not likely to
  spread among broiler producers.

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Treatment of NE outbreak

• Speed is essential -gt via drinking water
• Many antibiotics are likely to be effective.
• Tylosin, OTC, Bacitracin, penicillin, neomycin,
  lincomycin, sulphonamides
• Considering
• Water solubility
• withdrawal periods
• cost
• activity against Gram bacteria
• Tylan soluble comes up as the antibiotic of
  choice when tested against these criteria.

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Building the wall of protection
When the clostridial enteritis challenge
overcomes the wall of protection, then Tylan
Soluble is the product of choice for first line
treatment.
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UK positioning

• NE and cholangio prevention (Strategic)
  0.1g/litre for two days around day 15
• 0.25g per litre for days one, two and three
• Dysbacteriosis0.1g per litre for two days
  immediately the condition is seen
• Treatment of necrotic enteritis0.1g per litre
  for two days immediately the condition is seen

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Tylan treatment of NE Conclusions - Brennan
Trial

• 1) Treatment with dietary Tylan (50-300 ppm)
  following NE onset
• reduced (Plt0.05) NE mortality and lesion score
• improved (Plt0.05) final bodyweight and feed
  conversion
• 2) 50 ppm dietary Tylan was adequate for
  mortality reduction
• 3) 100 ppm Tylan was required for optimum
  reduction of lesion score, and optimum
  improvement of feed efficiency and growth

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Further steps

• NE model is extreme due to
• high challenge dose
• simultaneous infection of entire study population
• Study with Tylan Water Soluble
• an effective NE treatment
• presentation pending (PSA, 2001)

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Cholangiohepatitis

• The liver is enlarged and firm
• Distended bile ducts (seen as blue color), are
  visible in the right lobe.
• Histologically fibrosing hepatitis,
  proliferation of the bile ducts, multiple
  granulomas and compressed hepatocytes.

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Cholangiohepatitis

• Can cause excessive downgrading of between 3 and
  5 of all chickens.
• Clostridium perfringens is usually isolated,
  antibiotic therapy in the young bird will control
  its development.

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Cholangiohepatitis

• CP infection of the liver
• Clinical disease is not always seen
• birds are condemned at the factory with jaundice,
  perihepatitis and pericarditis
• History may show a blip in mortality during the
  growout
• Antibiotic therapy will prevent the syndrome

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Experimental work

• Onderka et al (1990) in Canada
• Experimental reproduction of cholangiohepatitis
• ligating the bile ducts
• injecting CP into the bile duct
• above occurred on day 21
• Results
• 5 days p.l. bile duct proliferation
• 6 days p.l. intensely yellow droppings
• 10 to 14 days p.l. liver changes
• 17 days p.l. enlarged tan coloured liver,
  speckled appearance

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Experimental work

• Sasaki et al, 2000
• 10 week old chickens
• ligation and inoculation with CH
• necropsy 2 weeks later

Inoculation of cystohepatic duct did not result
in CH, it had to accompanied by ligation of the
enterohepatic duct.
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Dysbacteriosis

• Presence of a qualitatively and/or quantitatively
  abnormal flora in the small intestine.
• This causes a clinical disorder and/or
  malabsorption.
• In Holland the incidence has increased since 1995
  from 0.3 to 5.6.

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Emerging problem

• Growth retardation around the 23rd day of
  grow-out.

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Names

• Feed passage - Turkey
• Hit the wall
• Flushing
• Vent pasting - Pakistan
• Summer gut
• Clostridial enteritis - Hungary
• Dysbacteriosis - W-Europe
• SIBO (Small Intestinal Bacterial Overgrowth)

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Features associated with the disease

• GP's loose some of the constrains on intestinal
  bacterial growth rates which will benefit from
  the use of slowly digested ingredients.
• Undigested feed is a potential substrate for
  bacterial fermentation.
• Variations in the nutritional quality of the
  ingredients are of increased relevance.
• Use of enzymes is benefitial.
• Fish meal worsens the problem.
• Coccidiosis control is also of great interest.
• Source Bedford, Worlds Poultry Science Journal
  56(4) 347-365 2000 Dec

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Symptoms

• The faeces is looser, contains more fluid, is
  less consistent, color is lighter.
• The faeces is more viscous and sticky.
• The water/feed ratio is increased, the daily
  growth is reduced.
• Reduction in feed intake.

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Detection of symptoms

• A crate with a wire mesh, developed in Holland.

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Detection of symptoms

• The crate is placed in the house.
• Every day a fresh newspaper is placed under the
  wire mesh.
• Birds randomly hop onto the crate and defecate.
• The zone of fluid around the droppings can be
  observed.
• Good dropping - no fluid zone
• Clear, but limited zone - dysbacteriosis
• Large fluid zone - viral problems, E. coli.

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Etiology

• Starts with a bacterial overgrowth.
• Increased level of bacterial endotoxins.
• Leakage of the gut.
• Bacteria penetrate the liver, bloodstream.
• Secondary leg problems, femoral head necrosis.

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Diagnostic methods

• As Cl.p. is named a key pathogen, culturing gives
  a clear indications.
• Classical NE it's enough, confirming the
  classical post mortem.

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Diagnostic methods

• Dysbacteriosis appears without mortality or large
  lesions, with lower Cp levels.
• The need is to confirm the diagnosis with the
  symptoms of looser faeces, more fluid.
• Reduced growth, increased water/feed ratio.
• Culturing itself is not sufficient.
• Profiling of the intestinal population using PCR
  techniques seems promising.

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Improve understanding

• Culturing is not sufficient.
• The tradition of focusing on one pathogen is
  over.
• Profiling the bacterial - viral population helps
  in understanding.
• Multifactorial problems need new approaches.
• Profile of "normal" and "disease" must be set up.
• The effect of treatment could be evaluated by the
  return of the "normal" profile.

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Diagnosis

• Bacterial overgrowth has been demonstrated by
  Terminal Restriction Fragment Length
  Polymorphism.
• This method has demonstrated
• - the proximal intestine or normal birds has very
  low levels of bacteria,
• - whereas birds with dysbacteriosis have
  substantially higher bacterial numbers.
• Cp have been shown to contribute to this
  overgrowth.
• Post-treatment Tylan birds showed bacterial
  population similar to normal.

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Monitoring Microbial community structure/fingerpri
nting

• Panneman 2000
• Based on PCR and 16S ribosome analysis using a
  database of genes that relate to specific
  bacteria
• The PCR can differentiate between normal birds
  and birds suffering from dysbacteriosis
• PCR indicates that in dysbacteriosis there is an
  increase in bacterial numbers in the proximal
  duodenum

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Confirming the presence of Dysbacteriosis T-RFLP

• Terminal Restriction Fragment Length Polymorphism
• Isolate DNA from microorganisms
• Amplify 16S RNA gene by PCR
• Digest amplified DNA with specific restriction
  enzymes
• Determine the length of the products
• The length of the final products is related to
  one or a small group of microorganisms

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T-RFLP applicationBacteriological analysis of
the contents of the chicken intestinal tract
A8
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Analysis of the gel
Post Tylan Treatment