Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carretera Mérida-Xmatkuil, C. P, 97315, Mérida, Yucatán, México.
CONACYT - Facultad de Medicina Veterinaria y Zootecnia, Universidad Autónoma de Yucatán, Km 15.5 Carretera Mérida-Xmatkuil, C. P, 97315, Mérida, Yucatán, México.
Parasitol Res. 2023 Mar;122(3):833-845. doi: 10.1007/s00436-023-07780-z. Epub 2023 Jan 21.
This study developed and evaluated an in vitro rumen incubation (IVRI) method to describe the exsheathment kinetics of Haemonchus contortus third-stage infective larvae (L) in ruminal liquor (RL). The specific objectives were (i) to standardize the IVRI method to facilitate the contact between L and RL as well as the larval recovery, and (ii) to apply the IVRI method to describe the exsheathment kinetics of H. contortus and to select the best fitting nonlinear model. Incubation devices containing H. contortus larvae were incubated according to the IVRI technique in cattle RL or PBS. The incubation conditions included RL mixed with a nitrogen-rich media, maintained at 39 °C, with pH = 7.0, vented with CO and manual agitation. The larvae were recovered after 0, 1, 3, 6, 9, 12, and 24 h. The exsheathed and ensheathed larvae were counted to estimate the exsheathment (%) in RL or PBS. Exsheathment in RL was analyzed with nonlinear regression models: Exponential, Gompertz, Logistic, Log-Logistic, and Weibull. The models' fit was compared to select the one that best described the exsheathment kinetics. The exsheathment in RL reached 6.52%, 20.65%, 58.22%, 69.24%, 73.08%, and 77.20% in 1, 3, 6, 9, 12, and 24 h, respectively. Although the Gompertz, Weibull, and Logistic models were adequate to describe the observed exsheathment, the Log-Logistic model had the best fit. The IVRI method using bovine RL represents a suitable tool for the study of the in vitro exsheathment kinetics of H. contortus L.
本研究开发并评估了一种体外瘤胃孵育（IVRI）方法，以描述旋毛虫第三期感染幼虫（L）在瘤胃液（RL）中的脱鞘动力学。具体目标是（i）标准化 IVRI 方法，以促进 L 与 RL 接触以及幼虫回收，（ii）应用 IVRI 方法描述旋毛虫的脱鞘动力学，并选择最佳拟合非线性模型。含有旋毛虫幼虫的孵育装置根据 IVRI 技术在牛 RL 或 PBS 中孵育。孵育条件包括 RL 与富含氮的培养基混合，保持在 39°C，pH=7.0，用 CO 通风并手动搅拌。孵育 0、1、3、6、9、12 和 24 h 后回收幼虫。计数脱鞘和鞘状幼虫，以估计 RL 或 PBS 中的脱鞘率（%）。使用非线性回归模型分析 RL 中的脱鞘：指数、戈珀兹、逻辑、对数逻辑和威布尔。比较模型的拟合度，以选择最能描述脱鞘动力学的模型。RL 中的脱鞘在 1、3、6、9、12 和 24 h 时分别达到 6.52%、20.65%、58.22%、69.24%、73.08%和 77.20%。虽然戈珀兹、威布尔和逻辑模型足以描述观察到的脱鞘，但对数逻辑模型拟合度最佳。使用牛 RL 的 IVRI 方法代表了研究旋毛虫 L 体外脱鞘动力学的合适工具。
