LEUKOENCEPHALOMALACIA IN EQUINES IN THE NORTH OF PARANA, BRAZIL

A total of 14 episodes of leukoencephalomalacia was related in North of Parana, during the period of July 1985 to September 1989. All of the feeds, obtained from the farms involved in the intoxication cases, had corn as main ingredient. Mycological study and mycotoxin determination were undertaken in 16 samples of 5 mixed feeds, 8 maizes, 2 granulated feeds and 1 hay. The counting, isolation and identification of the fungal strains were determined using coconut agar added with 0,5% triton X-100 plus antibiotics and potato dextrose agar. The 13 Fusarium moniliforme strains isolated from the feeds involved in the intoxication cases were submited to single spore isolation and analysed for acute toxicity, injecting the concentrate obtained from rice culture extract, intraperitonially in the mouse. The presence of aflatoxins, ochratoxin A, sterigmatocystin and zearalenone in the feed samples was determined by the method of Soares & Rodrigues-Amaya. The total mould count ranged from 10(2) to 10(8) CFU/g of product. It consisted mainly of F. moniliforme, Penicilium sp and Aspergillus flavus group, isolating also Mucoraceae, Aspergillus terreus and Neurospora sp. The feed samples without thermal processing had high F. moniliforme contamination, with Fusarium like colony count, varying from 10(5) to 10(8) CFU/g in 11 samples. Zearalenone was detected in samples taken from 5 establishments. Feed components impeded the zearalenone analysis in other 5 samples. Tests for the presence of T-2 toxin, diacetoxyscirpenol, roridin A and verrucarin in 5 feed samples gave negative results. None of the mouse inoculated with F. moniliforme culture extract presented neither acute intoxication syntoms, nor macroscopically significant lesions. In the pellet feeds involved in the intoxication, the absence of F. moniliforme in a sample and low fungal contamination in another, suggested their elimination during feed production. On the other hand, it showed that leukoencephalomalacia's toxin is resistant enough to support heat treatment used for feed processing.