Abstract：
This study applied the in vitro rumen exsheathment test (IVRET) to evaluate the exsheathment kinetics of Haemonchus contortus infective larvae (L3) incubated in ruminal liquor (RL) containing acetone:water extracts of Acacia pennatula (AP), Gymnopodium floribundum (GF), Havardia albicans (HA) or Lysiloma latisiliquum (LL). The role of polyphenols in the biological activity of the evaluated extracts was also determined. Larvae were incubated in RL either alone or added with a different plant extract (AP, GF, HA, or LL) at 1200 μg/mL. Polyethylene glycol (PEG) was added to block polyphenols in each treatment (RL+PEG, AP+PEG, GF+PEG, HA+PEG, and LL+PEG). After incubation times of 0, 1, 3, 6, 9, and 24 h, the exsheathment process was stopped to count the number of ensheathed and exsheathed L3. A Log-Logistic model was used to determine the L3 exsheathment kinetics in the different RL treatments. The inflection point of the respective kinetic curves, which indicates the time to reach 50 % exsheathed L3 (T50), was the only parameter that differed when comparing the exsheathment models (99 % probability of difference). The T50 values obtained for GF, HA, and LL treatments (T50 = 7.11 - 7.58 h) were higher in comparison to the T50 of RL (5.72 h) (≥ 70 % probability of difference). The L3 incubated in RL added with GF, HA, and LL extracts delayed their exsheathment at 3 and 6 h of incubation (28.71 - 48.06 % exsheathment reduction) compared to the RL treatment. The T50 value for AP, AP+PEG, GF+PEG, HA+PEG, and LL+PEG were similar to RL and RL+PEG (T50 = 5.34 - 6.97 h). In conclusion, the IVRET can be used to identify plants with the potential to delay the exsheathment of H. contortus L3 in the ruminal liquor. The acetone:water extracts of G. floribundum, H. albicans, and L. latisiliquum delayed the T50 of H. contortus exsheathment, which was evident at 3 and 6 h of incubation in ruminal liquor. The observed exsheathment delay was attributed to the polyphenol content of the extracts.
摘要：
本研究应用体外瘤胃出鞘试验（IVRET）评估了在含丙酮的瘤胃液（RL）中孵育的扭曲血汗感染幼虫（L3）的出鞘动力学：金合欢（AP）的水提取物，金盘草（GF），白色哈瓦迪虫（HA）或lysilomalatisiliquum（LL）。还确定了多酚在评估的提取物的生物活性中的作用。幼虫在RL中单独孵育或添加不同的植物提取物(AP，GF,HA,或LL)为1200μg/mL。在每次处理中加入聚乙二醇(PEG)以阻断多酚(RL+PEG,AP+PEG,GF+PEG,HA+PEG,和LL+PEG)。在0、1、3、6、9和24h的孵育时间后，停止出鞘过程以计算出鞘和出鞘L3的数量。使用Log-Logistic模型来确定不同RL处理中的L3出鞘动力学。各个动力学曲线的拐点，这表明达到50%出鞘L3(T50)的时间，是比较出鞘模型时唯一不同的参数(99%的差异概率)。获得的GF的T50值，HA,与RL的T50（5.72h）相比，LL治疗（T50=7.11-7.58h）更高（差异概率≥70％）。L3在添加GF的RL中孵育，HA,与RL处理相比，LL提取物在孵育3小时和6小时延迟了出鞘（出鞘减少28.71-48.06％）。AP的T50值，AP+PEG,GF+PEG,HA+PEG,LL+PEG与RL和RL+PEG相似(T50=5.34-6.97h)。总之,IVRET可用于鉴定具有延迟瘤胃液中H.contortusL3出鞘的潜力的植物。丙酮：G.floribundum的水提取物，H.白色念珠菌,和L.latisiliquum延迟了H.contortus出鞘的T50，在瘤胃液中孵育3和6小时时很明显。观察到的出鞘延迟归因于提取物的多酚含量。
