School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
Vet Parasitol. 2010 Oct 29;173(3-4):307-16. doi: 10.1016/j.vetpar.2010.06.035. Epub 2010 Jul 3.
This paper describes two experiments conducted to examine the acaricidal potential of spinosad against the poultry red mite, Dermanyssus gallinae (De Geer), a serious ectoparasitic pest of laying hens. Spinosad is a natural product derived from the fermentation of the micro-organism Saccharopolyspora spinosa. In vitro testing confirmed that, when applied to a galvanised metal plate to the point of run-off, spinosad was toxic to adult female D. gallinae and suggested that at an application rate of 3.88 g/L a significant residual toxicity of spinosad could be achieved for up to 21 days. A subsequent in vivo experiment in a conventional cage housing system for laying hens demonstrated the acaricidal activity and residual toxicity to D. gallinae of a single application of spinosad when applied at either 1.94 or 3.88 g/L. Residual toxicity of spinosad at both of these application rates was maintained throughout the course of the 28 day post-spray study period, with a peak in product efficacy seen 14 days after spraying. The results suggest that the greater the D. gallinae population the greater will be the toxic effect of spinosad. Although the exact reasons for this are unclear, it can be speculated that conspecifics spread the product between each other more efficiently at higher mite population densities. However, further study is warranted to confirm this possibility. Application of spinosad in vivo had no effect on hen bodyweight or egg production parameters (number and weight), suggesting that this product could be used to effectively control D. gallinae infestations whilst birds are in lay. This paper also describes a novel method for effectively and efficiently achieving replication of treatments in a single poultry house, previously unpopulated with D. gallinae. Individual groups of conventional cages were stocked with hens, seeded with D. gallinae and used as replicates. Independence of replicates was achieved by isolating cage groups from one another using a non-drying glue barrier to minimise D. gallinae migration. Creating isolated populations (replicates) of D. gallinae within a single poultry house thus represents a novel and efficient means of screening other potential acaricides under field conditions.
本文描述了两项实验，旨在研究多杀菌素对鸡皮刺螨（Dermanyssus gallinae）的杀螨潜力，鸡皮刺螨是一种严重的家禽体外寄生虫，危害产蛋鸡。多杀菌素是一种天然产物，来源于微生物嗜糖多孢菌（Saccharopolyspora spinosa）的发酵。体外测试证实，当多杀菌素施用到镀锌金属板直至流干时，对成年雌性鸡皮刺螨具有毒性，并表明在 3.88g/L 的施用量下，多杀菌素的显著残留毒性可持续长达 21 天。随后在传统笼养系统中进行的一项体内实验表明，在 1.94 或 3.88g/L 的剂量下，单次使用多杀菌素对鸡皮刺螨具有杀螨活性和残留毒性。在 28 天的喷雾后研究期间，这两种施用量的多杀菌素残留毒性都得到了维持，在喷雾后 14 天达到了产品功效的峰值。结果表明，鸡皮刺螨种群越大，多杀菌素的毒性作用就越大。虽然确切原因尚不清楚，但可以推测，在较高的螨密度下，同种生物之间会更有效地传播产品。然而，需要进一步的研究来证实这一可能性。多杀菌素在体内的应用对母鸡体重或产蛋参数（数量和重量）没有影响，这表明该产品可用于在鸟类产蛋期间有效控制鸡皮刺螨的感染。本文还描述了一种在未被鸡皮刺螨污染的单个家禽养殖场中有效且高效地实现处理复制的新方法。将单个常规鸡笼组饲养母鸡，接种鸡皮刺螨，并作为重复使用。通过使用不干燥的胶状屏障将鸡笼组彼此隔离，以最大限度地减少鸡皮刺螨的迁移，从而实现重复之间的独立性。因此，在单个家禽养殖场内创建鸡皮刺螨的孤立种群（重复）代表了一种在田间条件下筛选其他潜在杀螨剂的新颖且高效的方法。
