Transcript Intestinal Integrity

Intestinal Integrity and the
Impact of Losing It
Elanco Poultry Health Conference
International Poultry Exposition
Atlanta
17 January 2001
Digestive Tract Structure
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Gut is a tube
Completely lined by
epithelial cells (enterocytes)
Continuous with epithelial
cells of skin at mouth and
cloaca
Contents of gut are “outside”
of the body
Selective absorption of
nutrients
Courtesy of Dr. Fred Hoerr, AVDL
Digestive Tract Structure
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Villi
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Absorptive surface
increased by fingerlike folds in the lining
Courtesy of Dr. Fred Hoerr, AVDL
Epithelium
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Epithelial cells
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Continuously line
villi
Physical barrier to
foreign agents,
materials
Surface further
increased by
microvilli
Courtesy of Dr. Fred Hoerr, AVDL
Intestinal Integrity
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Biological barrier
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Epithelial cells that line the intestine
Protective secretory products of epithelial
cells
Tissues and processes that support integrity
of the epithelial lining
Courtesy of Dr. Fred Hoerr, AVDL
Intestinal Fluid Dynamics
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2 Grams fluid secretion
for each 1 Gram
digesta
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Nutrient solution
Pathogen dilution and
flushing
Secreted from crypts
and sides of villi
Absorption from tip and
from large intestine
Courtesy of Dr. Fred Hoerr, AVDL
Unbalanced Fluid Dynamics
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Net secretion > absorption = diarrhea
Decreased absorption
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Damaged absorptive cells
Increased osmolality of digesta
Increased secretion
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Bacterial enterotoxins
Viruses
Inflammatory mediators
Courtesy of Dr. Fred Hoerr, AVDL
Mucus Secretion
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Goblet cells
Water and glycoprotein
Lubricates flow of digesta
Protects from autodigestion
by gastric acid, pepsin, and
digestive enzymes
Increased secretion by
noxious stimuli
Barrier to bacteria and fungi
Courtesy of Dr. Fred Hoerr, AVDL
Agents that Degrade Mucus
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Candida albicans
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Helicobacter pylori
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Mucinolytic enzyme
Adherence and penetration
Secretes urease
Destroys protective gastric
mucus
Under- heated soy meal
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Urease
Courtesy of Dr. Fred Hoerr, AVDL
The Lamina Propria
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Connective tissue to
support villus
Blood and lymph vessels
GALT: Gut Associated
Lymphoid Tissue
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B and T lymphocytes
Plasma cells
Macrophages
Courtesy of Dr. Fred Hoerr, AVDL
The Lamina Propria
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Gut continuously
exposed to foreign
agents
Lamina propria and
GALT responds with
normal reactivity
Normal vs. Disease
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Biological
Economic
Gut Histopathology of
88 Broiler Flocks
7
Mean Cumulative Score 1
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Gastric
Intestinal
6
5
4
3
2
1
0
3
4
5
Weeks of Age
Courtesy of Dr. Fred Hoerr, AVDL
6
7
Injury to the Lamina Propria
and GALT
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Bursal Disease
Chicken Infectious
Anemia
Marek’s Disease
Hemorrhagic Enteritis
(turkeys)
Immunosuppressive
mycotoxins
Courtesy of Dr. Fred Hoerr, AVDL
Virus Injury to Intestine
From: Moon, 1997
Courtesy of Dr. Fred Hoerr, AVDL
Bacterial Enteritis
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Poultry litter
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Exposure to opportunistic
bacterial pathogens
Potential primary pathogens
Courtesy of Dr. Fred Hoerr, AVDL
Bacteria: Enterotoxins
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Clostridium
perfringens
Escherichia coli
Campylobacter
Courtesy of Dr. Fred Hoerr, AVDL
Bacteria: Attach and Efface
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Clostridium perfringens
Escherichia coli
Courtesy of Dr. Fred Hoerr, AVDL
Bacteria: Invasion
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Salmonella spp.
Liver
Courtesy of Dr. Fred Hoerr, AVDL
Protozoa
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Coccidia
Histomonas
Liver
Courtesy of Dr. Fred Hoerr, AVDL
Intestinal Toxicity
Absorption
Digestion
Secretion
Immature
Digestion
Renewal
Courtesy of Dr. Fred Hoerr, AVDL
Bağırsak Sağlığının Kaybı
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Sindirilmemiş yem ve ishal
Büyüme geriliği
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Bağırsak hastalığı
Sistemik hastalık
Mortalite
Courtesy of Dr. Fred Hoerr, AVDL
Sindirilmemiş Yem ve İshal
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Dışkıda sindirilmemiş yem parçaları
Yemin emiliminde aksama
Malabsorption/maldigestion
Şunlarla ilişkilidir:
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FCR ve canlı ağırlık artışında
bozulma
Karkas veriminde azalma
Üretim maliyetinde artış
Management sorunları
Courtesy of Dr. Fred Hoerr, AVDL
Sindirilmemiş Yem
Sendromunun Mekanizması
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Secretory ishal
Ozmotik ishal
Malabsorpsiyon
Exudative hastalık
Courtesy of Dr. Fred Hoerr, AVDL
Secretory İshal
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Bağırsak mukozasından aşırı sıvı sızması
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Virüsler
Bakteriyel enterotoksinler
Courtesy of Dr. Fred Hoerr, AVDL
Ozmotik İshal
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Ozmotik güçlerin artışı
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Yüksek tuz oranına sahip rasyonlar
Ozmotik ve fiziksel faktörlerin bileşkesi
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Rasyon kaynaklı faktörler (non-starch
polysaccharides) in barley, rye, wheat, and
other grains
Courtesy of Dr. Fred Hoerr, AVDL
Beta-glucans in Barley
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Gelling effect blocks digestive enzymes,
bile acids, and absorption of nutrients
undigested sugars
opportunistic bacteria
need for antibiotics
size GI tract
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cecum overload
Supplemental enzymes partially alleviate
Courtesy of Dr. Fred Hoerr, AVDL
Malabsorption
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Output of voluminous, bulky feces with
increased osmolarity owing to unabsorbed
nutrients
Defective intraluminal digestion
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Antinutritional factors
Damaged mucosa with immature enterocytes
Decreased digestive secretions (lipase, amylase)
Courtesy of Dr. Fred Hoerr, AVDL
Exudative Disease
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Diarrhea with presence of
hemorrhage and detritus from
necrotic tissue and inflammation
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Loss of enterocytes, fluid,
electrolytes, and plasma
Escape of pathogen to
other tissues
Diversion of nutrients for
inflammation and repair
Courtesy of Dr. Fred Hoerr, AVDL
Exudative Disease
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Necrotic enteritis
Coccidiosis
Salmonellosis
Histomoniasis
Courtesy of Dr. Fred Hoerr, AVDL
Intestinal Integrity
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Maintained
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Challenged
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Host defenses: intestinal lining cells, secretory
products, and support tissues
Exposure to opportunistic and virulent pathogens
Dietary and management factors that increase
exposure
Destroyed
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Virulent, primary pathogens
Additive, synergistic injury by variable exposure to
opportunistic pathogens
Courtesy of Dr. Fred Hoerr, AVDL
Dose of
Pathogens
Emerging Issues
Host
Resistance
Virulence of
Pathogens
Dose of Pathogens
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Goal: Decreased exposure
Feed ingredient production and poultry
rearing are biological systems
Diminishing list of pharmacological
products to suppress bacteria
Actions to reduce exposure must meet
biological, economic, and regulatory
justification
Virulence of Pathogen
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Ability to colonize, establish and maintain
infection
Least practical control point
Under genetic control of pathogen
Antibiotics may influence bacterial
virulence
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Inhibit protein metabolism
Improved Host Resistance
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Genetic selection in presence of limited
pharmacological and biological products
Understanding and preventing
immunosuppression
Diet selection and enzyme efficacy
Improved oral vaccines to protect mucosal
surfaces
Thank you