Sodium toxicosis in chickens: case series (2014–2023) and literature review

Cases of sodium toxicosis (ST), although reported infrequently, can result in acute morbidity and mortality and extensive losses in affected poultry. We analyzed the clinical, pathologic, and toxicologic findings of 7 diagnosed cases of ST in chicken autopsy submissions at the California Animal Health & Food Safety Laboratory System (CAHFS), University of California-Davis, from 2014 to 2023. We also evaluated the brain sodium concentrations in 10 clinically normal broiler chickens to elucidate potential differences with salt-intoxicated chickens, and reviewed the literature of field cases of ST in chickens and turkeys. Lesions of anasarca described in the 7 ST cases (66 chickens) identified from the CAHFS database included: ascites (62 of 66; 6 of 7 cases); hydropericardium and cardiomegaly (54; 6 of 7); edematous, congested lungs (24; 6 of 7); enlarged, pale kidneys (24; 6 of 7); subcutaneous edema (17; 4 of 7); cystic testes (14; 6 of 7); and cerebral edema (7; 4 of 7). Brain sodium concentrations exceeded 1,800 ppm in only 4 of 24 brains analyzed in our case series. In the feed samples analyzed from 5 ST cases, sodium concentrations exceeded the recommended 2,000 ppm; concentrations detected were 2,500-12,000 ppm. In brains from the 10 clinically normal chickens evaluated, brain sodium concentrations were 1,500-1,700 ppm.