Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carretera Mérida-Xmatkuil, C.P. 97315 Mérida, Yucatán, Mexico.
CONAHCYT - Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carretera Mérida-Xmatkuil, C.P. 97315 Mérida, Yucatán, Mexico.
Vet Parasitol. 2024 Apr;327:110135. doi: 10.1016/j.vetpar.2024.110135. Epub 2024 Jan 20.
This study adapted the in vitro rumen incubation (IVRI) method to evaluate the biological activity of a Gymnopodium floribundum leaves extract against the exsheathment of Haemonchus contortus infective larvae (L), and to determine the role of plant polyphenols on the biological activity. The incubation protocol followed the IVRI method, adding polyethylene glycol (PEG) as a polyphenol-blocking agent. The L were incubated in ruminal liquor (RL), ruminal liquor with PEG (RL+PEG), ruminal liquor with G. floribundum extract (RLE), and ruminal liquor with G. floribundum extract and PEG (RLE+PEG). Incubation condition controls included phosphate buffered saline (PBS), PBS with PEG (PBS+PEG), incubation medium (without ruminal liquor) (IM), and incubation medium with PEG (IM+PEG). The L were recovered after incubation times of 0, 1, 3, 6, 9, and 24 h (39 °C). The respective L exsheathment kinetics were estimated for the different treatments (RL, RL+PEG, RLE, and RLE+PEG) using Log-Logistic models. The parameters of the different models were compared to determine the impact of the extract, with or without PEG, on the L exsheathment kinetics. The exsheathment in PBS and PBS+PEG remained < 2.71% at each incubation time. The exsheathment in IM and IM+PEG reached 13.58% and 17.18% at 24 h, respectively. The exsheathment percentages for RLE were lower than those for RL at 3, 6 and 9 h of incubation. The inflection point, indicating the time required to reach 50% of the maximal exsheathment (T), was the only parameter that differed between the ruminal liquor models. The T in RLE (7.106 h) was higher than the values obtained for RL (5.385 h) and RL+PEG (4.923 h) (99.99% probability of being different). Such delay resulted in a reduction of exsheathment in RLE of 62% at 3 h, 38% at 6 h, and 12% at 9 h, relative to RL values. When PEG was added with the extract (RLE+PEG), the T (5.045 h) was similar to that of RL and RL+PEG. The IVRI method was adapted as an in vitro rumen exsheathment test (IVRET). The IVRET showed that H. contortus L exposed to G. floribundum extract delayed their exsheathment kinetics at different time points. The exsheathment delay was attributed to the polyphenol content of the extract.
本研究采用体外瘤胃孵育（IVRI）方法评估 Gymnopodium floribundum 叶提取物对捻转血矛线虫感染幼虫（L）出壳的生物学活性，并确定植物多酚在生物活性中的作用。孵育方案遵循 IVRI 方法，添加聚乙二醇（PEG）作为多酚阻断剂。将 L 在瘤胃液（RL）、含 PEG 的瘤胃液（RL+PEG）、含 Gymnopodium floribundum 提取物的瘤胃液（RLE）和含 Gymnopodium floribundum 提取物和 PEG 的瘤胃液（RLE+PEG）中孵育。孵育条件对照包括磷酸盐缓冲盐水（PBS）、含 PEG 的磷酸盐缓冲盐水（PBS+PEG）、孵育培养基（无瘤胃液）（IM）和含 PEG 的孵育培养基（IM+PEG）。L 在 39°C 下孵育 0、1、3、6、9 和 24 小时后回收。使用 Log-Logistic 模型分别估计不同处理（RL、RL+PEG、RLE 和 RLE+PEG）中 L 出壳的动力学。比较不同模型的参数，以确定提取物（有无 PEG）对 L 出壳动力学的影响。在每个孵育时间，PBS 和 PBS+PEG 中的出壳率均<2.71%。IM 和 IM+PEG 在 24 小时时分别达到 13.58%和 17.18%的出壳率。在孵育 3、6 和 9 小时时，RLE 的出壳率低于 RL。表示达到最大出壳率 50%所需时间（T）的拐点是瘤胃液模型之间唯一不同的参数。RLE 的 T（7.106 小时）高于 RL（5.385 小时）和 RL+PEG（4.923 小时）的值（99.99%的概率存在差异）。这种延迟导致 3 小时、6 小时和 9 小时时 RLE 的出壳率分别降低 62%、38%和 12%，与 RL 值相比。当提取物中添加 PEG 时（RLE+PEG），T（5.045 小时）与 RL 和 RL+PEG 相似。IVRI 方法被改编为体外瘤胃出壳试验（IVRET）。IVRET 表明，暴露于 Gymnopodium floribundum 提取物的 H. contortus L 在不同时间点延迟了它们的出壳动力学。出壳延迟归因于提取物中的多酚含量。
