Casteel S W, Rottinghaus G E, Johnson G C, Wicklow D T
Veterinary Medical Diagnostic Laboratory, College of Veterinary Medicine, University of Missouri, Columbia 65211, USA.
Vet Hum Toxicol. 1995 Jun;37(3):248-51.
Normally innocuous forages are sporadically associated with hepatogenous photosensitization outbreaks at certain times of the year or when grown and harvested during unusual environmental conditions, such as periods of excessive rainfall. Allegations of livestock illness following consumption of such moldy hays are associated with clinical syndromes uncharacteristic of known forage-related diseases, suggesting that unidentified toxin(s) may be responsible. This study was instigated by field observations of hepatogenous photosensitization in cattle fed alfalfa-grass forage. To document the toxic nature of the hay, large bales of hay (450 kg) were fed, ad libitum, to 3 groups of 2 calves each. Elevated serum liver enzymes provided evidence of hepatobiliary disease. Gamma glutamyl transferase activities in serums of the calves sustained at least a 10-fold increase above baseline during the feeding trials. Histologic examination of liver biopsies and postmortem sections revealed mild periportal fibrosis and biliary hyperplasia. Culture material from 12 fungal isolates from the hay failed to induce liver disease in calves.
通常无害的草料在一年中的某些时候，或者在异常环境条件下生长和收获时（如降雨过多的时期），会偶尔引发肝源性光敏反应疫情。食用此类发霉干草后出现牲畜疾病的说法，与已知草料相关疾病不典型的临床综合征有关，这表明可能存在未鉴定的毒素。本研究是由对饲喂苜蓿 - 禾本科草料的牛发生肝源性光敏反应的实地观察引发的。为了证明干草的毒性，将大捆干草（450千克）随意喂给3组，每组2头犊牛。血清肝酶升高提供了肝胆疾病的证据。在饲喂试验期间，犊牛血清中的γ-谷氨酰转移酶活性至少比基线水平高出10倍。肝活检和死后切片的组织学检查显示轻度门周纤维化和胆管增生。从干草中分离出的12种真菌菌株的培养物未能在犊牛中诱发肝病。
