Confirming the promise to prevent physiological disorders of organs: urolithiasis in laying hens

Several problems caused by organ system disorders, such as urolithiasis (kidney stone formation) in laying hens, occur sporadically in poultry flocks and are likely to remain unresolved unless the scientific method is rigorously applied to develop and validate a research model for inducing similar pathology in experimental flocks. Successful research models confirm key triggering mechanisms and stressors, reveal innate organ system limitations or susceptibilities, and provide a reliable test bed for evaluating practical prophylactic and therapeutic strategies. Researchers have a professional responsibility to confirm their research model's limitations and relevance before making recommendations to poultry producers. Our experiments confirmed that feeding diets containing high Ca with low available phosphorus (HCLP) to experimental groups of immature pullets consistently triggered the pathognomonic symptoms associated with field outbreaks of urolithiasis. The HCLP research model also demonstrated that affected hens would survive and remain in production when their dietary cation: anion balance was adjusted to acidify the urine and thereby solubilize the kidney stones. Urinary acidification was rapidly adopted as the method of choice for treating commercial flocks experiencing outbreaks of urolithiasis.