Molan A L, Hoskin S O, Barry T N, McNabb W C
Nutrition Group, AgResearch, Grasslands Research Centre, Palmerston North, New Zealand.
Vet Rec. 2000 Jul 8;147(2):44-8. doi: 10.1136/vr.147.2.44.
The inhibitory activity of condensed tannins extracted from four forage legume plants were evaluated by using a larval migration inhibition assay. The first (L1) and third (L3) stages of deer lungworm (Dictyocaulus viviparus), and the third stage (L3) of deer gastrointestinal nematodes were incubated with tannins extracted from Lotus pedunculatus, Lotus corniculatus, sulla (Hedysarum coronarium) and sainfoin (Onobrychus viciifolia). The tannins extracted from all the forages had inhibitory activity as measured by their ability to paralyse the larvae and inhibit them from passing through sieves. At the highest concentration used (1200 microg/ml) the tannins extracted from sainfoin had the highest activity against ensheathed L1 lungworm larvae (58 per cent), followed by L. pedunculatus (45 per cent), sulla (42 per cent) and L. comiculatus (35 per cent) when the larvae were incubated at 37 degrees C. The same trend, but with lower activities, was observed when the larvae were incubated at 22 degrees C. Anthelmintic activity against L3 lungworm larvae was evaluated by measuring the death rate of ensheathed L3 larvae after incubation with condensed tannins for two, 24 and 48 hours at room temperature (22 degrees C). The death rate was significantly higher (P<0.001) after 48 hours incubation than after two hours or 24 hours, and significantly higher (P<0.001) after 24 hours than after two hours incubation. Condensed tannins from sainfoin had the highest inhibitory activity followed by L. pedunculatus, sulla and L. comiculatus. The tannins from sainfoin also had the highest activity against L3 larvae of gastrointestinal nematodes, followed by L. pedunculatus, sulla and L. comiculatus. Exsheathed larvae of gastrointestinal nematodes were significantly more susceptible to the action of the tannins than ensheathed larvae.
采用幼虫迁移抑制试验评估了从四种豆科牧草植物中提取的缩合单宁的抑制活性。将鹿肺线虫（网尾线虫）的第一期幼虫（L1）和第三期幼虫（L3）以及鹿胃肠道线虫的第三期幼虫（L3）与从百脉根、角豆树、 sulla（冠状岩黄芪）和红豆草中提取的单宁一起孵育。从所有牧草中提取的单宁均具有抑制活性，可通过其使幼虫麻痹并抑制其穿过筛网的能力来衡量。在使用的最高浓度（1200微克/毫升）下，当幼虫在37℃孵育时，红豆草提取的单宁对有鞘L1肺线虫幼虫的活性最高（58%），其次是百脉根（45%）、sulla（42%）和角豆树（35%）。当幼虫在22℃孵育时，观察到相同趋势，但活性较低。通过在室温（22℃）下将有鞘L3幼虫与缩合单宁孵育2小时、24小时和48小时后测量其死亡率，评估了对L3肺线虫幼虫的驱虫活性。孵育48小时后的死亡率显著高于2小时或24小时（P<0.001），孵育24小时后的死亡率显著高于2小时（P<0.001）。红豆草中的缩合单宁抑制活性最高，其次是百脉根、sulla和角豆树。红豆草中的单宁对胃肠道线虫L3幼虫的活性也最高，其次是百脉根、sulla和角豆树。胃肠道线虫的脱鞘幼虫比有鞘幼虫对单宁的作用更敏感。
