Institute of Nutritional Physiology 'Oskar Kellner', Leibniz Institute for Farm Animal Biology, Wilhelm-Stahl-Allee 2, 18196, Dummerstorf, Germany.
Institute of Nutritional Physiology 'Oskar Kellner', Leibniz Institute for Farm Animal Biology, Wilhelm-Stahl-Allee 2, 18196, Dummerstorf, Germany.
Vet Parasitol. 2020 Jul;283:109158. doi: 10.1016/j.vetpar.2020.109158. Epub 2020 May 31.
Faecal egg counting techniques (ECTs) are useful tools for assessing anthelmintic efficacy and selecting hosts resistant to parasite infection. McMaster (MM) is one of the most commonly used ECTs, but it suffers from low sensitivity and precision. Mini-FLOTAC (MF) has been proposed to replace MM, but so far has not been evaluated for gastro-intestinal nematode infections in chickens. This study compared sensitivity, precision, and accuracy of MM and MF with two trials using egg-spiked faecal samples ranging from 50-1250 eggs per gram of faeces (EPG). In addition, effects of two flotation fluids with different specific gravities (SG), namely salt (SG = 1.20) and sucrose solutions (SG = 1.32), on accuracy and time-spent for both ECTs were evaluated. Overall sensitivity based on the composite reads across all EPG-levels was 97.1 % for MM and 100 % for MF. MF was, however, more sensitive (P = 0.003) or tended to (P = 0.087) be more sensitive than MM at only the lowest EPG-level (i.e. 50 EPG) using one of the duplicate reads, whereas there was no significant difference at any EPG-level using composite reads. Overall average precision of MF (79.5 %) was higher (P < 0.001) than that of MM (63.4 %) across all EPG-levels. Precision of MM increased from 22 to 87 % with increasing EPG-levels from 50-1250 EPG. Corresponding precision estimates for MF ranged from 76 to 91 %. Overall recovery rate of MM (74.6 %) was significantly higher (P < 0.001) than that of MF (60.1 %). There was no significant difference in recovery rate of spiked-eggs among different EPG-levels (P = 0.833). Recovery rate of MM ranged from 64 % to 79 % across different EPG-levels, while it ranged from 54 % to 64 % with MF without an interaction between ECT and EPG-level (P = 0.701). It took more time (P < 0.001) to process (prepare and read) samples with MF than with MM using the same flotation fluid. The sugar solution tended to (P = 0.100) increase egg-recovery with both ECTs, while increasing (P < 0.001) time-spent for processing the samples. Our data collectively suggest that MM is less sensitive than MF only at around minimum detection level of MM when using unrepeated reads. We conclude that McMaster is faster, relatively more accurate but less precise than Mini-FLOTAC. The sugar solution with higher SG increases accuracy of both techniques at the expense of increased labour time.
粪便卵计数技术（ECTs）是评估驱虫效果和选择对寄生虫感染具有抗性的宿主的有用工具。麦克马斯特（MM）是最常用的 ECT 之一，但它的灵敏度和精度都较低。Mini-FLOTAC（MF）已被提议取代 MM，但迄今为止，它尚未在鸡的胃肠道线虫感染中进行评估。本研究比较了 MM 和 MF 在两项试验中的灵敏度、精度和准确性，这两项试验使用的粪便样本中含有 50-1250 个每克粪便卵（EPG）的卵。此外，还评估了两种比重（SG）不同的浮选液（盐，SG=1.20 和蔗糖溶液，SG=1.32）对两种 ECT 的准确性和花费时间的影响。基于所有 EPG 水平的复合读数，MM 的总体灵敏度为 97.1%，MF 的总体灵敏度为 100%。然而，MF 在仅使用重复读数之一的最低 EPG 水平（即 50 EPG）时，更敏感（P=0.003）或倾向于比 MM 更敏感（P=0.087），而在使用复合读数时，在任何 EPG 水平上均无显着差异。在所有 EPG 水平上，MF 的平均精度（79.5%）均高于 MM（63.4%）（P<0.001）。MM 的精度从 50-1250 EPG 的 EPG 水平从 22%增加到 87%。MF 的相应精度估计值范围为 76%至 91%。MM 的总体回收率（74.6%）明显高于 MF（60.1%）（P<0.001）。在不同的 EPG 水平之间，受感染卵的回收率没有差异（P=0.833）。MM 的回收率范围为 64%至 79%，而 MF 的回收率范围为 54%至 64%，ECT 和 EPG 水平之间没有相互作用（P=0.701）。使用相同的浮选液，处理（准备和读取）MF 样本比 MM 样本花费的时间更多（P<0.001）。糖水倾向于（P=0.100）提高两种 ECT 的卵回收率，同时增加（P<0.001）处理样本的时间。我们的数据综合表明，仅在使用未重复读数时，MM 的灵敏度才低于 MF ，而在最低检测水平左右。我们得出的结论是，麦克马斯特比迷你-FLOTAC 更快，相对更准确但精度较低。比重较高的糖水会提高两种技术的准确性，但会增加劳动力时间。
