Roberts C A, Spiers D E, Karr A L, Benedict H R, Sleper D A, Eichen P A, West C P, Piper E L, Rottinghaus G E
University of Missouri, Columbia 65211, USA.
J Agric Food Chem. 2002 Sep 25;50(20):5742-5. doi: 10.1021/jf020336n.
Experimental cultivars of the pasture grass tall fescue are infected with unique strains of the fungal endophyte Neotyphodium coenophialum, which produce low concentrations of ergot alkaloids. A rat model was evaluated as a tool for rapid, initial screening of experimental cultivars considered to be nontoxic. Rats were fed diets that included seed from experimental cultivars of tall fescue with introduced strains of N. coenophialum and a toxic control diet containing seed of the cultivar Kentucky 31 (KY31), with its endemic strain of N. coenophialum. Rats were preconditioned to a nontoxic diet and then fed treatment diets for 13 days with 5 days at thermoneutrality (21 degrees C) followed by 8 days under heat stress (31 degrees C). For most of the 13-day treatment period, rats fed KY31 exhibited depressed daily intake compared to those fed diets of cultivars with introduced endophytes (P < 0.05). In addition, rats fed KY31 exhibited significantly less weight than rats on other diets after heat treatment was imposed. For all initial trials and repeated trials, total intake and total gain calculated at the end of each trial were the most consistent indicators of toxicity.
牧草高羊茅的实验品种感染了真菌内生菌共生黑麦草的独特菌株，这些菌株产生低浓度的麦角生物碱。大鼠模型被评估为一种用于快速初步筛选被认为无毒的实验品种的工具。给大鼠喂食的日粮包括含有引入共生黑麦草菌株的高羊茅实验品种的种子，以及一种含有肯塔基31号（KY31）品种种子的毒性对照日粮，该品种带有其地方性共生黑麦草菌株。大鼠先适应无毒日粮，然后喂食处理日粮13天，其中5天处于热中性（21摄氏度），随后8天处于热应激（31摄氏度）。在13天的处理期的大部分时间里，与喂食引入内生菌品种日粮的大鼠相比，喂食KY31的大鼠每日摄入量降低（P < 0.05）。此外，在施加热处理后，喂食KY31的大鼠体重明显低于其他日粮组的大鼠。对于所有初始试验和重复试验，每次试验结束时计算的总摄入量和总增重是最一致的毒性指标。
