Transfer of an in vitro model for the evaluation of anticoccidial compounds

生物科学中体外模型（在活的有机体之外进行）的发展和广泛使用支持了许多科学进步，并大大减少了用于研究的实验动物的数量。由于在许多机构和公司不可能实施和管理饲养鸡的设施，因此对家禽疾病的研究可以显著受益于体外模型。在许多研究中，使用体外模型可以取代实验鸡，或者至少减少它们的使用。使用这些模型可以减少研究的总体时间和成本，支持更多的研究小组进行禽类疾病的研究。家禽之所以重要，是因为它是全世界供人类食用的动物蛋白的主要来源。鸡肉产品价格实惠，提供高质量的蛋白质，几乎没有宗教和文化障碍。尽管如此，许多疾病会影响鸡，影响肉和蛋生产的经济效益。球虫病是一种由单细胞寄生虫引起的全球性鸡病。这些寄生虫在鸡的肠道内迅速生长，导致疾病并迅速感染其他鸟类。球虫病的控制通常是通过在饲料中施用药物来实现的，然而，由于耐药性的出现、关于在农场动物中使用药物的新规定以及消费者的关切，全球药物的使用面临压力。因此，有必要研究具有抗寄生虫特性的新型化合物，以控制球虫病，并允许家禽业的扩张，以继续养活全球人口。目前，新化合物的抗寄生虫活性只能通过涉及大量鸡的昂贵活体实验来测试。鉴于对新化合物特性的需求增加，在皇家兽医学院，我们最近开发了一种体外细胞培养模型，可以评估新化合物在寄生虫中的作用。如果一种化合物没有表现出任何效果，就不需要在鸡身上进行试验（完全替代动物）。如果一种化合物显示出对寄生虫的相关作用，那么体外模型可以为设计进一步的鸡实验提供重要信息，有助于减少测试所需的组数（减少动物数量）。在该模型的第一个应用中，我们评估了两种精油的抗寄生虫特性。该结果使随后的体内（动物）实验中鸡的数量减少到67%。因此，该模型可能对全球减少用于球虫病抗寄生虫化合物研究的动物数量产生重要影响。然而，为了使体外模型具有全球影响，其他研究小组和研究新化合物的公司更广泛地采用是必要的。为此，我们在本项目中建议将模型优化并移交给SALUVET-innova，这是一家研发公司，将在ADIBIO和SETNA（动物营养公司）进行体内实验之前在体外实施模型和测试化合物-最终的现场条件下的体内测试对于产品的商业化总是必要的-。此外，我们还计划了一项传播策略，以便其他公司和研究人员更广泛地采用该模型。我们已经做了估计，通过体外预筛选，我们可以减少实验动物群体，在125只鸡中减少75只（60%）。这意味着，如果我们的模型每年测试10到20种新化合物，每年可以减少4000只鸡中的750- 1500只（每年用于测试化合物抗球虫病的鸡的平均数量），这意味着总体减少20-40%。

The development and wide use of in vitro models (performed outside of a living organism) in biosciences have supported many scientific advances as well as significantly reducing the number of experimental animals used in research. Research in poultry diseases could significantly benefit from in vitro models since implementing and managing the facilities to accommodate chickens is not possible in many institutions and companies. The use of in vitro models could replace experimental chickens in many studies or at least reduce their use. The use of these models could reduce overall time and costs of research, supporting an increased number of research groups conducting research in avian diseases. Poultry is important because it provides the principal source of animal protein for human consumption worldwide. Chicken products are affordable, providing high-quality protein and facing few religious and cultural barriers. Nonetheless, many diseases can affect chickens compromising the economics of meat and egg production. In particular, coccidiosis is a global disease of chickens caused by single-celled parasites. These parasites grow very quickly inside the gut of the chicken causing the disease and rapidly infecting other birds. The control of coccidiosis is usually achieved by administrating in-feed drugs, however, the use of drugs is under pressure globally, influenced by the emergence of resistance, new regulations about their use in farm animals as well as consumer concerns. In consequence, research in novel compounds with anti-parasitic properties is necessary to control coccidiosis and allow the expansion of the poultry industry to keep feeding the global population. At the moment, the anti-parasitic activity of new compounds can only be tested in live animals by expensive experiments that involve large numbers of chickens. At the light of this increased need for the characterisation of new compounds, at the Royal Veterinary College we have recently developed an in vitro cell culture model that can evaluate the effects of new compounds in the parasite. If a compound does not exhibit any effect, there would not be need for testing it in chickens (total replacement of animals). If a compound shows relevant effects on the parasite, the in vitro model can generate important information for the design of further experiments in chickens, helping to reduce the number of groups needed for testing (reduction in the number of animals). In a first application of the model, we evaluated the anti-parasitic properties of two essential oils. The results allowed reducing the number of chicken in the subsequent in vivo (performed in animals) experiments to 67%. Therefore, this model could have an important impact in the global reduction of the number of animals used for research in anti-parasitic compounds against coccidiosis. Nevertheless, to allow the in vitro model having a global impact, a wider uptake by other research group and companies studying novel compounds is necessary. With this aim, we propose in this project the optimisation and transfer of the model to SALUVET-innova, a R&D company that will implement the model and test compound from ADIBIO and SETNA (animal nutrition companies) in vitro before they perform in vivo experiments - final in vivo tests in field conditions are always necessary for the commercialisation of the product -. In addition, we have planned a communication strategy for a wider uptake of the model by other companies and researchers. We have done the estimation that with the in vitro pre-screening we could reduce experimental animal groups achieving a reduction of 75 out of 125 chickens (60%) per compound tested. This means that if 10 to 20 new compounds are tested per year by our model, a reduction of 750-1,500 chickens out of 4,000 (average number of chickens per year used to test compounds against coccidiosis) could be achieved per annum, meaning a 20-40% overall reduction.