Schultze A E, Rohrbach B W, Fribourg H A, Waller J C, Oliver J W
Department of Pathology, College of Veterinary Medicine, University of Tennessee, Knoxville 37901-1071, USA.
Vet Hum Toxicol. 1999 Jun;41(3):133-9.
Tall fescue (Festuca arundinacea) is a forage grass that is widely used in pastures in the eastern US for cattle, sheep and horses. The endophytic fungus Neotyphodium coenophialum is endemic in tall fescue pastures in the US. The turfgrass industry intentionally infects fescue cultivars with strains of the fungus to impart desirable growth and disease tolerance qualities to the plants. In contrast, ergot and pyrrolizidine alkaloid toxins produced by fungus-infected plants have been incriminated causally in bovine tall fescue toxicosis, a poorly defined syndrome of morbidity that occurs in cattle that consume endophyte-infected tall fescue (E+TF). We compared the serum biochemistry profiles from cattle that grazed E+TF with those from control cattle that grazed on endophyte-free tall fescue (E-TF). Cattle were bled on 7 dates from April 1 to August 30, 1996 and on 5 dates from May 1 to July 30, 1997. Cattle that grazed E+TF retained rough winter haircoats and had lesser weight gains, typical of tall fescue toxicosis, compared to those grazing E-TF. They had decreased activities of alkaline phosphatase and alanine aminotransferase. Compared to controls, they had lower values for serum prolactin and globulin concentrations. The concentration of creatinine and the albumin/globulin ratio were increased in the cattle grazing E+TF. Isozyme determination of alkaline phosphatase indicated that the decrease in serum activity of cattle grazing E+TF was due to decreases in both intestinal and bone isozymes. Serum protein electrophoresis indicated that the decrease in serum globulin concentration was due to decreases in both alpha and gamma globulin fractions of this protein. The data collected in these experiments add to our understanding of the alterations that occur in the serum chemistry profiles when cattle consume E+TF for prolonged periods of time.
高羊茅（Festuca arundinacea）是一种牧草，在美国东部的牧场中广泛用于饲养牛、羊和马。内生真菌Neotyphodium coenophialum在美国的高羊茅牧场中普遍存在。草坪草行业有意用该真菌菌株感染高羊茅品种，以使植物具有理想的生长和抗病能力。相比之下，真菌感染植物产生的麦角生物碱和吡咯里西啶生物碱毒素被认为是牛高羊茅中毒的病因，这是一种发生在食用内生真菌感染的高羊茅（E+TF）的牛身上的定义不明确的发病综合征。我们比较了放牧E+TF的牛与放牧无内生真菌高羊茅（E-TF）的对照牛的血清生化指标。1996年4月1日至8月30日期间，在7个日期采集牛血样；1997年5月1日至7月30日期间，在5个日期采集牛血样。与放牧E-TF的牛相比，放牧E+TF的牛保留着粗糙的冬季毛发，体重增加较少，这是高羊茅中毒的典型症状。它们的碱性磷酸酶和丙氨酸转氨酶活性降低。与对照组相比，它们的血清催乳素和球蛋白浓度较低。放牧E+TF的牛的肌酐浓度和白蛋白/球蛋白比值升高。碱性磷酸酶同工酶测定表明，放牧E+TF的牛血清活性降低是由于肠道和骨同工酶均降低。血清蛋白电泳表明，血清球蛋白浓度降低是由于该蛋白的α和γ球蛋白组分均降低。这些实验收集的数据增进了我们对牛长期食用E+TF时血清化学指标变化的理解。
