Made available in DSpace on 2016-04-28T20:18:26Z (GMT). No. of bitstreams: 1 Bruno Jose Martini Santos1.pdf: 1883262 bytes, checksum: 395f219cf3935956cd50161c96cd1a19 (MD5) Previous issue date: 2010-02-10 / The administration of the aerial parts of Pteridium arachnoideum during 15 to 57 days in proportions that varied from 50 to 75% of the supplied grass (Pennicetum purpureum) mixed with hay of bracken fern, caused in 3 of the 4 experimental horses, a clinical and pathological picture that can be attributed to the thiaminases, one of the poisonous principles of the plant. The clinical picture consisted, in a progressive way, apathy, lethargy, sleepiness, hyporrexia with evolution to anorexia, reluctance in moving, increase of heart frequency, arrhythmia and sternal decubitus passing to lateral decubitus. The decubitus lasted at the most 48 hours. In this phase, the clinical signs previously observed got more intense; additionaly the animals refused water, made attempts of getting up without success, made intense intermittent peddling movements, followed by dyspnoea, had muscular tremors, tonic muscle spasms of limbs, opistotonus, intense sweating and finally death. The electrocardiographic analysis showed hydropericardium and myocardial failure in the last 48 hours before death. Post-mortem and histopathological examinations did not show significant lesions, unless congestion in various organs, indicating congestive heart failure. Clinical pathology revealed, in relation to the blood count, in one of the three horses, anemia in the final part of the experiment, and trombocitopenia in only two. No changes were seen in the leucograma. Parallel to a fall of serous thiamine, an increase the pyruvic acid was seen in the three animals. One of the experimental horses developed a taste for the fern, and the other two only consumed the P. arachnoideum-grass mixture with addition of sugar. / A administra??o das partes a?reas de Pteridium arachnoideum durante per?odos de 15 a 57 dias na propor??o que variou de 50 a 75% da mistura com capim (Pennicetum purpureum) fornecida, causou em 3 dos 4 equinos do experimento um quadro cl?nico-patol?gico que pode ser atribu?do a tiaminase, um dos princ?pios t?xicos da planta. No quadro cl?nico foram verificados de forma progressiva apatia, letargia, sonol?ncia, hiporrexia com evolu??o para anorexia, relut?ncia em se movimentar, aumento da frequ?ncia card?aca, arritmia e finalmente dec?bito esternal passando para o lateral. O dec?bito era de no m?ximo 48 horas. Nesta fase os sinais cl?nicos anteriormente observados se intensificaram, os animais, recusavam ?gua, faziam tentativas de se levantar sem sucesso, movimentos de pedalagem intensos intermitentes, seguidos de dispn?ia, tremores musculares, espasmos musculares t?nicos dos membros, opist?tono, sudorese intensa e finalmente morte. As an?lises eletrocardiogr?ficas indicaram hidroperic?rdio e insufici?ncia mioc?rdica nas ultimas 48 horas antes da morte. Os achados de necropsia e os exames histopatol?gicos n?o revelaram altera??es significativas, a n?o ser congest?o em diversos ?rg?os e efus?es cavit?rias de colora??o amarelo ocre, o que est? relacionado com insufici?ncia card?aca congestiva. A patologia cl?nica revelou, em rela??o ao hemograma, em um dos tr?s animais, anemia na parte final do experimento, e em dois equinos trombocitopenia. O leucograma n?o apresentou altera??es. Paralelamente a queda da tiamina s?rica, foi verificado um aumento do ?cido pir?vico nos tr?s animais. Um dos animais experimentais desenvolveu um gosto pela samambaia, os outros dois consumiram a mistura de capim com feno de samambaia mediante o acr?scimo de a??car.