title: Interaction of ionophore and vitamin E in knockdown syndrome of turkeys.
abstract: Monensin and vitamin E concentrations, as well as histopathology of skeletal muscles and myocardium, were evaluated in broad-breasted white turkeys kept in commercial facilities. Turkeys with knockdown syndrome had myopathy of skeletal muscles, but no lesions in the myocardium. Generally, concentration of monensin in serum was highest in turkeys diagnosed with knockdown syndrome given more than 90 mg/kg of monensin in the diet, followed by turkeys diagnosed with knockdown syndrome given <90 mg/kg of monensin in the diet, healthy turkeys fed a diet that contained <90 mg/kg of monensin, and finally healthy turkeys fed a diet free of monensin (not detectable). However, the concentration of monensin was highly variable within each group, and the median was lower than the average. Vitamin E concentrations in the livers varied from low-normal to below normal and were statistically higher in healthy turkeys fed a diet free of monensin than in the livers of birds from the 3 groups exposed to monensin. This suggests that the concentration of monensin in serum positively correlates to the severity of clinical signs and pathology and to the amount of monensin in the feed. Although the methodology developed to detect serum monensin concentrations is beneficial and accurate for case investigations, it is recommended that several samples from each flock be evaluated because of variation within a flock. The current study also suggests that monensin in the feed could induce lower concentrations of vitamin E in the liver of turkeys and can predispose the turkeys to knockdown syndrome.
authors.affiliation: California Animal Health and Food Safety Laboratory, University of California Davis, Fresno, CA 93725, USA. rmcrespo@ucdavis.edu
authors.forename: Rocio
authors.initials: R
authors.lastname: Crespo
authors.forename: H L
authors.initials: HL
authors.lastname: Shivaprasad
authors.forename: Franz
authors.initials: F
authors.lastname: Sommer
authors.forename: Birgit
authors.initials: B
authors.lastname: Puschner
mesh_terms: D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000981:Antiprotozoal Agents / Q000008:administration & dosage / Q000009:adverse effects / Q000097:blood; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D004347:Drug Interactions; D008099:Liver / Q000737:chemistry; D008985:Monensin / Q000008:administration & dosage* / Q000009:adverse effects* / Q000097:blood; D018482:Muscle, Skeletal / Q000473:pathology; D009135:Muscular Diseases / Q000139:chemically induced / Q000662:veterinary*; D011201:Poultry Diseases / Q000473:pathology*; D014422:Turkeys; D014810:Vitamin E / Q000008:administration & dosage* / Q000009:adverse effects* / Q000032:analysis; D014815:Vitamins / Q000008:administration & dosage / Q000009:adverse effects / Q000032:analysis
chemical_list: D000981:Antiprotozoal Agents; D014815:Vitamins; D014810:Vitamin E; D008985:Monensin