Schreurs N M, Molan A L, Lopez-Villalobos N, Barry T N, McNabb W C
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand.
Vet Rec. 2002 Sep 21;151(12):348-53. doi: 10.1136/vr.151.12.348.
This study determined the in vitro effects on the viability of internal parasites of grazing undrenched weaner deer on either chicory (Cichorium intybus) or perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) pasture. One experiment investigated the hatching and development of gastrointestinal nematode eggs and larvae, and the development and motility of L1 lungworm (Dictyocaulus eckerti) larvae, and a second experiment used larval migration inhibition assays to test the viability of L1 lungworm larvae extracted from the faeces of weaner deer grazed on either chicory or pasture when they were incubated with rumen and abomasal fluids from fistulated deer also grazing on chicory or pasture. The incubations were undertaken with and without added condensed tannins purified from chicory and with or without polyethylene glycol (PEG) to bind the tannins. Chicory had no effect on the hatching and development of gastrointestinal nematode eggs and larvae. Grazing chicory reduced the number of lungworm larvae developing to the L3 stage, and L1 lungworm larvae from the faeces of chicory-grazed deer were less viable in rumen and abomasal fluid than larvae from pasture-grazed animals. Abomasal fluid was significantly (P < 0.001) less inhibitory to the migration of L1 lungworms than rumen fluid. When the larvae were incubated in rumen and abomasal fluids from chicory-grazed deer, their passage through sieves was significantly (P < 0.001) reduced in comparison with when they were incubated in the fluids from pasture-grazed deer Adding condensed tannins to rumen fluid increased the inhibition of the migration of L1 lungworm larvae but PEG removed this inhibition; this effect was not observed with abomasal fluid.
本研究测定了放牧于菊苣（菊苣属）或多年生黑麦草（黑麦草属）/白三叶（白三叶属）牧场上未进行驱虫的断奶鹿体内寄生虫的体外生存能力。一项实验研究了胃肠道线虫卵和幼虫的孵化与发育，以及第一期肺线虫（埃氏网尾线虫）幼虫的发育与活力，另一项实验采用幼虫迁移抑制试验，以测试从放牧于菊苣或牧场上的断奶鹿粪便中提取的第一期肺线虫幼虫，在与同样放牧于菊苣或牧场上的瘘管鹿的瘤胃液和皱胃液一起孵育时的生存能力。孵育过程中添加或不添加从菊苣中纯化的缩合单宁，以及添加或不添加聚乙二醇（PEG）以结合单宁。菊苣对胃肠道线虫卵和幼虫的孵化与发育没有影响。放牧于菊苣上可减少发育至第三期的肺线虫幼虫数量，且来自放牧于菊苣的鹿粪便中的第一期肺线虫幼虫在瘤胃液和皱胃液中的生存能力低于放牧于牧场的动物的幼虫。皱胃液对第一期肺线虫迁移的抑制作用明显（P < 0.001）低于瘤胃液。当幼虫在放牧于菊苣的鹿的瘤胃液和皱胃液中孵育时，与在放牧于牧场的鹿的胃液中孵育相比，其通过筛网的通过率显著（P < 0.001）降低。向瘤胃液中添加缩合单宁可增强对第一期肺线虫幼虫迁移的抑制作用，但PEG可消除这种抑制作用；在皱胃液中未观察到这种效果。
