A nematode trapping fungus, Duddingtonia flagrans (Df), fed to sheep is useful for biocontrol of gastrointestinal nematodes on pasture. The objectives were: 1) validate methods to determine viability of a commercial source of Df before beginning research studies, and 2) examine the interaction between Df and dietary coccidiostat (as decoquinate). Methods: Study 1: In Jan 2023, weaned Katahdin lambs (97.3 ± 1.2 d of age; 19.5 ± 1.3 kg BW; packed cell volume of 26.5 ± 1.4 %), naturally infected with predominantly Haemonchus contortus (89%) and mean fecal egg count (FEC) of 6,860 ± 1,535 eggs/g, were randomly assigned to: 1) no Df (-g)/(FEC-g)×100]. Study 2: In Aug 2023, 7 mo old anthelmintic-treated ram lambs (FEC < 50 egg/s; 51.6 ± 3.9 kg in BW) were fed grain supplement daily with decoquinate (Deccox; +C) or without (-C; n = 3/diet) on d -7 to 1, and, within diet, administered 3 g BioWorma/d in 6 gel capsules (+DF; n = 2/diet) or not (-DF; n = 1) on d -1 and -2. Fecal samples were collected on d 0 (2 g/plate + 300 L3 of H. contortus) and d 1 (6 g/plate + 1000 L3) and placed on water agar plates (n = 3/lamb) at 25°C. Trapping structures were visually assessed after 24, 48, and 144 h (6 d), and cultures Baermannized on d 7 for L3 recovery. Relative reduction was (x̅-DF-C-x̅+DF+C/ x̅-DF-C)×100%. Data for variables collected one time were analyzed by Proc GLM (SAS), and for those collected serially, a Proc Mixed with repeated measures. A 2×2 factorial was used in Study 2 and included treatments, day and interaction in model. Results: Study 1: As expected, L3 recovery was reduced (P = 0.005) in DF lambs by 67-78% relative to control. Study 2: DF formed loops and traps around L3 by d 6 and reduced L3 recovery on both days (P < 0.001) without an interaction by decoquinate (P = 0.69). The L3 reduction relative to -DF-C was between 60.2-73.5%. The coccidiostat, decoquinate, can be added to the diet in the presence of BioWorma without antagonism. In conclusion, the in vitro studies allow detection of adverse issues with viability of Df and can reduce the number of animals needed for research studies.

中文翻译：

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61 测定 Duddingtonia flagrans 的体内和体外捕食活性以及与饮食抗球虫剂的相互作用

饲喂绵羊的线虫捕获真菌 Duddingtonia flagrans (Df) 可用于牧场胃肠道线虫的生物防治。目标是：1) 在开始研究之前验证确定 Df 商业来源可行性的方法，2) 检查 Df 和膳食球虫抑制剂（如癸氧喹酯）之间的相互作用。方法： 研究 1：2023 年 1 月，断奶的 Katahdin 羔羊（97.3 ± 1.2 天龄；19.5 ± 1.3 kg 体重；细胞堆积体积 26.5 ± 1.4 %），自然感染主要是捻转血矛线虫（89%）和平均粪便卵计数 (FEC) 为 6,860 ± 1,535 个鸡蛋/g，随机分配至：1) 无 Df (-g)/(FEC-g)×100]。研究 2：2023 年 8 月，7 个月大的经过驱虫药治疗的公羊羔（FEC < 50 蛋/秒；体重 51.6 ± 3.9 kg）每日饲喂含癸氧喹酯（Deccox；+C）或不含（-C；-C；C）的谷物补充剂。 n = 3/饮食）在第 -7 至 1 天，并且在饮食中，在 6 粒凝胶胶囊中每天服用 3 g BioWorma（+DF；n = 2/饮食）或在 d 不服用（-DF；n = 1） -1和-2。在第 0 天（2 g/板 + 300 L3 捻转）和第 1 天（6 g/板 + 1000 L3）收集粪便样本，并置于 25°C 的水琼脂平板上（n = 3/羔羊）。24、48 和 144 小时（6 天）后对捕获结构进行目视评估，并在第 7 天对培养物进行贝尔曼化以进行 L3 恢复。相对减少量为(x̅-DF-C-x̅+DF+C/x̅-DF-C)×100%。一次收集的变量数据由 Proc GLM (SAS) 进行分析，对于连续收集的变量数据，由 Proc Mixed 与重复测量进行分析。研究 2 中使用了 2×2 因子，包括模型中的治疗、天数和相互作用。结果：研究 1：正如预期的那样，与对照相比，DF 羔羊的 L3 恢复降低了 67-78%（P = 0.005）。研究 2：DF 在第 6 天时在 L3 周围形成环和陷阱，并在两天内降低 L3 恢复 (P < 0.001)，而没有与癸喹酯相互作用 (P = 0.69)。L3相对于-DF-C的减少在60.2-73.5%之间。球虫抑制剂癸氧喹酯可以在 BioWorma 存在的情况下添加到饮食中，而不会产生拮抗作用。总之，体外研究可以检测 Df 活力的不利问题，并可以减少研究所需的动物数量。