Narasin poisoning in turkeys
Sályi, G.; Szabó, E.; Bagó, G.; Bánhidi, G.; Szilägyi, M.
Acta Veterinaria Hungarica 36(1-2): 107-115
1988
ISSN/ISBN: 0236-6290 PMID: 3202044 Document Number: 311487
Mass disease and a considerable mortality rate (over 32%) are reported from a turkey flock of 3000 birds aged 11 weeks. As a cause, narasin posioning has been incriminated. The most characteristic clinical signs were locomotor disorders. These were accompanied by severe dyspnoea and moderate diarrhoea. At necropsy, in the mass muscles there was muscle fibre damage, in most cases visible with the unaided eye. Histologically, the lesions proved to be Zenker's degeneration and necrosis. In addition catarrhal enteritis, renal degeneration and, in several cases, pulmonary congestion were observed. Nearly one-third of the flock died within one week after the clinical signs first appeared. The highest mortality occurred among the toms. The ration consumed by the turkeys had contained 42.8 mg/kg (40-50 mg/kg) narasin, slightly "contaminated" with monensin. In feeding trials conducted with batches of the original ration containing somewhat less ionophore antibiotics (about 28 mg/kg), the clinical signs and gross lesions characteristic of narasin toxicity could be elicited in turkeys of similar age (10 weeks) as in the field cases; however, it took longer for the clinical signs to appear than in the affected flock. The present results support the observations of British authors (Davis, 1983 Simpson, 1984) that turkeys are highly sensitive to narasin, and that rations containing a small fraction of the therapeutic narasin dose established for broiler chickens might cause considerable losses among turkeys.