Aspectos clínicos e laboratoriais em ovinos submetidos a dietas com níveis elevados de enxofre com objetivo de indução de polioencefalomalácia

Abstract

Pesq. Vet. Bras. 33(4): 435-442, abril 2013 435 RESUMO.-A polioencefalomalacia (PEM) é uma doença neurológica que acomete ruminantes e pode ser desencadeada por diversos fatores, dentre eles o consumo excessivo de enxofre. Este trabalho teve como objetivo verificar a relação entre dietas ricas em enxofre, altos níveis de gás sulfídrico ruminal e a ocorrência de polioencefalomalácia em ovinos. Foram utilizados 18 ovinos, divididos em três grupos (G1, G2 e G3) que receberam diferentes níveis de enxofre na dieta; 0,2%, 0,9% e 1,2%, respectivamente. Exames físicos (frequência cardíaca, frequência respiratória, temperatura retal e motricidade ruminal) e complementares (concentração de sulfeto de hidrogênio ruminal, hemogasometria venosa, pH do fluído ruminal, concentração de cobre sérico e hepático, tomografia computadorizada, ne- is a neuropathologic condition of ruminants that can be induced by a variety of factors including excessive sulfur intake. This study aimed to investigate the relationship between diets rich in sulfur, high levels of ruminal hydrogen sulfide and the occurrence of polioencephalomalacia in sheep. Eighteen sheep were divided into three groups (G1, G2, and G3) and supplemented with 0.2%, 0.9% and 1.2% sulfur in the diet respectively. Clinical evaluation (i.e. heart rate, respiratory rate, rectal temperature and rumen motility) and laboratory exams (i.e. ruminal hydrogen sulfide concentration, venous gas analysis, ruminal pH, serum and liver copper concentration, computed axial tomography, necropsy, and histopathological examination) were performed. Rectal temperature, venous gas and ruminal pH were within normal limits. Tachycardia and tachypnea were observed in sheep of the three groups. Rumen motility was decreased in animals of group G2 and G3 when compared with G1. The higher the sulfur intake, the lower was the serum and liver levels of copper. Increased ruminal hydrogen sulfide concentration was detected in G2 and G3 sheep. None of the animals had clinical signs of PEM. Computed axial tomography, macroscopic and histopathological examination of the central nervous system showed no evidence of PEM. It is suggested that other factors are associated with excessive sulfur consumption for a PEM outbreak to occur in sheep.INDEX TERMS: Cerebrocortical necrosis, polioencephalomalacia, sulfur, ruminal hydrogen sulfide, sheep.

Polioencephalomalacia in ruminants from the semi-arid region of Rio Grande do Norte, Brazil

“…However, nowadays, not all cases of PEM are associated with thiamine deficiency, and several other etiologies are involved in the pathogenesis of this lesion (SANT'ANA et al, 2009b). Among these causes, we may highlight manifestations of excess sulfur intake (LONERAGAN et al, 1998;CUNHA et al, 2010CUNHA et al, , 2011DELFIOL et al, 2013), salt (OSWEILER et al, 1995;DUARTE et al, 2014), lead intoxication (CEBRA; CEBRA, 2004;LEMOS et al, 2004), and thiamine deficiency SANT'ANA et al, 2009b;GRAÇA et al, 2010) or analogues, such as amprolium (SANT'ANA et al, 2009a;NOGUEIRA et al, 2010), besides ingestion of plants rich in thiaminase, and acute poisoning by Phalaris spp. and by bovine herpesvirus type-5 SANT'ANA et al, 2009b).…”

Equívocos arraigados no meio pecuário sobre deficiências e suplementação minerais em bovinos no Brasil

“…Outro ponto, ainda sob investigação, é a possível relação entre a polioencefalomalácia e o consumo excessivo de enxofre, sob forma de sulfatos, por ruminantes (Goud 2000, Delfiol et al 2013). Também é necessário lembrar que o excesso de S pode causar a deficiência secundária de cobre.…”