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Intestinal Integrity and the Impact of Losing It

Intestinal Integrity and the Impact of Losing It. Elanco Poultry Health Conference International Poultry Exposition Atlanta 17 January 2001. Digestive Tract Structure. Gut is a tube Completely lined by epithelial cells (enterocytes)

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Intestinal Integrity and the Impact of Losing It

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  1. Intestinal Integrity and the Impact of Losing It Elanco Poultry Health Conference International Poultry Exposition Atlanta 17 January 2001

  2. Digestive Tract Structure • 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

  3. Digestive Tract Structure • Villi • Absorptive surface increased by finger-like folds in the lining Courtesy of Dr. Fred Hoerr, AVDL

  4. Epithelium • Epithelial cells • Continuously line villi • Physical barrier to foreign agents, materials • Surface further increased by microvilli Courtesy of Dr. Fred Hoerr, AVDL

  5. Intestinal Integrity • Biological barrier • 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

  6. Intestinal Fluid Dynamics • 2 Grams fluid secretion for each 1 Gram digesta • 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

  7. Unbalanced Fluid Dynamics • Net secretion > absorption = diarrhea • Decreased absorption • Damaged absorptive cells • Increased osmolality of digesta • Increased secretion • Bacterial enterotoxins • Viruses • Inflammatory mediators Courtesy of Dr. Fred Hoerr, AVDL

  8. Mucus Secretion • 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

  9. Agents that Degrade Mucus • Candida albicans • Mucinolytic enzyme • Adherence and penetration • Helicobacter pylori • Secretes urease • Destroys protective gastric mucus • Under- heated soy meal • Urease Courtesy of Dr. Fred Hoerr, AVDL

  10. The Lamina Propria • Connective tissue to support villus • Blood and lymph vessels • GALT: Gut Associated Lymphoid Tissue • B and T lymphocytes • Plasma cells • Macrophages Courtesy of Dr. Fred Hoerr, AVDL

  11. The Lamina Propria • Gut continuously exposed to foreign agents • Lamina propria and GALT responds with normal reactivity • Normal vs. Disease • Biological • Economic Gut Histopathology of 88 Broiler Flocks Courtesy of Dr. Fred Hoerr, AVDL

  12. Injury to the Lamina Propria and GALT • Bursal Disease • Chicken Infectious Anemia • Marek’s Disease • Hemorrhagic Enteritis (turkeys) • Immunosuppressive mycotoxins Courtesy of Dr. Fred Hoerr, AVDL

  13. Virus Injury to Intestine From: Moon, 1997 Courtesy of Dr. Fred Hoerr, AVDL

  14. Bacterial Enteritis • Poultry litter • Exposure to opportunistic bacterial pathogens • Potential primary pathogens Courtesy of Dr. Fred Hoerr, AVDL

  15. Bacteria: Enterotoxins • Clostridium perfringens • Escherichia coli • Campylobacter Courtesy of Dr. Fred Hoerr, AVDL

  16. Bacteria: Attach and Efface • Clostridium perfringens • Escherichia coli Courtesy of Dr. Fred Hoerr, AVDL

  17. Bacteria: Invasion • Salmonella spp. Liver Courtesy of Dr. Fred Hoerr, AVDL

  18. Protozoa • Coccidia • Histomonas Liver Courtesy of Dr. Fred Hoerr, AVDL

  19. Intestinal Toxicity Absorption Digestion Secretion Immature Digestion Renewal Courtesy of Dr. Fred Hoerr, AVDL

  20. Bağırsak Sağlığının Kaybı • Sindirilmemiş yem ve ishal • Büyüme geriliği • Bağırsak hastalığı • Sistemikhastalık • Mortalite Courtesy of Dr. Fred Hoerr, AVDL

  21. Sindirilmemiş Yem ve İshal • Dışkıda sindirilmemiş yem parçaları • Yemin emiliminde aksama • Malabsorption/maldigestion • Şunlarla ilişkilidir: • FCR ve canlı ağırlık artışında bozulma • Karkas veriminde azalma • Üretim maliyetinde artış • Management sorunları Courtesy of Dr. Fred Hoerr, AVDL

  22. Sindirilmemiş Yem Sendromunun Mekanizması • Secretory ishal • Ozmotikishal • Malabsorpsiyon • Exudative hastalık Courtesy of Dr. Fred Hoerr, AVDL

  23. Secretory İshal • Bağırsak mukozasından aşırı sıvı sızması • Virüsler • Bakteriyel enterotoksinler Courtesy of Dr. Fred Hoerr, AVDL

  24. Ozmotikİshal • Ozmotik güçlerin artışı • Yüksek tuz oranına sahip rasyonlar • Ozmotik ve fiziksel faktörlerin bileşkesi • Rasyon kaynaklı faktörler (non-starch polysaccharides) in barley, rye, wheat, and other grains Courtesy of Dr. Fred Hoerr, AVDL

  25. Beta-glucans in Barley • Gelling effect blocks digestive enzymes, bile acids, and absorption of nutrients undigested sugars cecum overload opportunistic bacteria need for antibiotics size GI tract • Supplemental enzymes partially alleviate Courtesy of Dr. Fred Hoerr, AVDL

  26. Malabsorption • Output of voluminous, bulky feces with increased osmolarity owing to unabsorbed nutrients • Defective intraluminal digestion • Antinutritional factors • Damaged mucosa with immature enterocytes • Decreased digestive secretions (lipase, amylase) Courtesy of Dr. Fred Hoerr, AVDL

  27. Exudative Disease • Diarrhea with presence of hemorrhage and detritus from necrotic tissue and inflammation • 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

  28. Exudative Disease • Necrotic enteritis • Coccidiosis • Salmonellosis • Histomoniasis Courtesy of Dr. Fred Hoerr, AVDL

  29. Intestinal Integrity • Maintained • Host defenses: intestinal lining cells, secretory products, and support tissues • Challenged • Exposure to opportunistic and virulent pathogens • Dietary and management factors that increase exposure • Destroyed • Virulent, primary pathogens • Additive, synergistic injury by variable exposure to opportunistic pathogens Courtesy of Dr. Fred Hoerr, AVDL

  30. Emerging Issues Dose of Pathogens Host Resistance Virulence of Pathogens

  31. Dose of Pathogens • 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

  32. Virulence of Pathogen • Ability to colonize, establish and maintain infection • Least practical control point • Under genetic control of pathogen • Antibiotics may influence bacterial virulence • Inhibit protein metabolism

  33. Improved Host Resistance • 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

  34. Thank you

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