Faedo M, Larsen M, Grønvold J
Danish Centre for Experimental Parasitology, The Royal Veterinary and Agricultural University, 100 Dyrlaegevej, DK-1870 Frederiksberg C, Denmark.
J Helminthol. 2002 Dec;76(4):295-302. doi: 10.1079/JOH2002130.
Two studies were conducted to investigate the growth and activity of the fungus, Duddingtonia flagrans, within cattle faecal pats. Artificial faecal pats were constructed with the centre separated from the outer layer by a nylon mesh. Eight treatments were tested, by varying the presence/absence of Cooperia oncophora eggs and fungal spores within each layer. With parasite eggs in the centre layer, a statistically lower recovery of larvae was observed compared to both pats with parasite eggs in the periphery and pats with parasite eggs throughout both layers. Regardless of location within the pat, if co-located with the parasite egg, D. flagrans was found to be effective in trapping developing larvae. The reduction in recovery of larvae from pats with parasite eggs and fungal spores in the centre was found to be significantly higher than when parasite eggs were in the centre and fungal spores in the periphery. In the second study, pats were made up in two treatments: pats containing fungal spores and C. oncophora eggs (fungus) and pats containing C. oncophora eggs (control). The pats were incubated at low or high humidity. Ten pats were used in a cross over where five pats incubated at low humidity for 7 weeks were removed, water added and then incubated at a high humidity for 1 week. Another five pats were incubated at a high humidity for 7 weeks, aerated and incubated at a low humidity for 1 week. There was no apparent growth of fungus in faecal pats incubated at a high humidity and less than 20% of larvae were recovered. The growth of D. flagrans was observed in faecal pats incubated at a low humidity, but a corresponding reduction in the percentage recovery of larvae did not occur, except in week 4. No statistical difference between fungal and control pats was seen in the change over pats. Nematophagous activity was assessed throughout the study and observed in the first 4 weeks within the pats containing fungus.
进行了两项研究，以调查牛粪便团中真菌——达丁顿草（Duddingtonia flagrans）的生长和活性。人工粪便团的构建方式是，中间部分通过尼龙网与外层隔开。通过改变每层中库柏线虫（Cooperia oncophora）虫卵和真菌孢子的有无，测试了八种处理方式。当虫卵位于中间层时，与虫卵位于外层的粪便团以及两层都有虫卵的粪便团相比，观察到幼虫的回收率在统计学上更低。无论在粪便团中的位置如何，只要与寄生虫卵共处，就发现达丁顿草能有效地捕获发育中的幼虫。发现中间层有寄生虫卵和真菌孢子的粪便团中幼虫回收率的降低显著高于虫卵在中间层而真菌孢子在外层的情况。在第二项研究中，粪便团分为两种处理方式：含有真菌孢子和库柏线虫虫卵的粪便团（真菌组）以及含有库柏线虫虫卵的粪便团（对照组）。粪便团在低湿度或高湿度条件下孵育。采用交叉试验，使用了十个粪便团，其中五个在低湿度下孵育7周后取出，加水，然后在高湿度下孵育1周。另外五个粪便团在高湿度下孵育7周，通气后在低湿度下孵育1周。在高湿度下孵育的粪便团中未观察到真菌的明显生长，幼虫回收率不到20%。在低湿度下孵育的粪便团中观察到达丁顿草的生长，但除第4周外，幼虫回收率并未相应降低。在交叉试验的粪便团中，真菌组和对照组之间未观察到统计学差异。在整个研究过程中评估了线虫捕食活性，并在含有真菌的粪便团中的前4周观察到了这种活性。
