Pathology of severe urolithiasis in a flock of egg-laying hens

Abstract

Fourteen, 31-week-old Lohmann white layers from a flock of 30,000 chickens had a history of apathy, and a drop in egg production. Clinical signs were observed in approximately 40% of the flock, and lasted for three months. Fourteen hens were euthanized for post-mortem examinations. Macroscopic findings included marked atrophy and loss of renal lobes along with compensatory renal hypertrophy of the contralateral lobe. Ureters were markedly dilated and filled with mucus and/or with molded white to yellow-grey uroliths that obliterated the lumen. At histopathology, the uroliths inside ureters and tubules were composed of concentrically arranged mineralized concretions, as well as urates associated with heterophilic infiltrations and epithelial hyperplasia. Renal parenchyma adjacent to obstructed ureters was compressed with tubules replaced by fibrous tissue. Multifocal interstitial lymphocytic nephritis, proteinuria and membranoproliferative glomerulonephritis were also found. Heterophilic and caseous ureteritis associated with numerous Gram-positive coccoid bacteria occurred in three chickens. Immunohistochemistry for avian coronavirus was negative. This negative result along with the case history indicated that water restriction was the most likely cause of mortality. This condition resulted in significant economic loss for this farmer.

Bone quality and incidence of urolithiasis in male broiler breeders fed a male or female ration.

“…Urolithiasis in poultry is not considered a single disease entity but is a manifestation of several renal dysfunctions resulting in renal damage or failure. Most studies report excess dietary Ca or P as a major cause among the infectious and non-infectious aetiologies of urolithiasis (Julian, 2005a, Lopes et al, 2021a, Guo et al, 2008. Incidences of urolithiasis in male breeders fed a female ration may occur because the female feed exceeds male recommended nutritional requirements (Moyle et al (2011).…”

“…Urolithiasis is a common condition in chickens, particularly in commercial breeders, although most reports have been on layer hens (Lopes et al, 2021a, Wideman Jr et al, 1985, Wideman, 2016. Urolithiasis reports have been associated with nutritional imbalances (high calcium, Ca:P imbalances and high protein diets), infectious diseases (infectious bronchitis virus and avian nephritis virus), and toxins (Moyle et al, 2011, Lopes et al, 2021b. However, the prevalence of urolithiasis in chickens may vary depending on several factors, including sex, breed, age, diet, and management practices.…”

“…However, research on other poultry revealed similar causes and post-mortem findings. In chickens, urolithiasis has been associated with multiple causes that can be infectious or noninfectious (Lopes et al, 2021a).…”