Intended and unintended consequences of the ZnO ban from pig diets on antimicrobial resistance, post-weaning diarrhoea and the microbiome.

猪日粮中禁用氧化锌对抗菌素耐药性、断奶后腹泻和微生物组的有意和无意的影响。

• 批准号: BB/Y004086/1
• 负责人: Deborah Hoyle
• 金额: $ 73.31万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FY004086%2F1
• 关键词: Intended; unintended; consequences; ZnO; ban

In most countries, farmed pigs are typically weaned at around four weeks of age. Young pigs are especially vulnerable to gut problems due to their immature digestive system and are particularly susceptible to a condition known as post-weaning diarrhoea. Post-weaning diarrhoea results in distress and discomfort in affected animals, and can lead to death. Recovered piglets often have poorer health and reduced growth, affecting welfare and farm productivity. Gastro-intestinal disease is currently the single most significant challenge to the sustainability of UK and global pig systems and affects more than half of pig farmers worldwide, at significant cost to the industry. Until recently, post-weaning diarrhoea was controlled by the addition of Zinc Oxide (ZnO) to feed after weaning, which reduced disease and improved piglet outcomes. However, due to concerns that ZnO contributes to the development of antibiotic resistance, prophylactic use of ZnO has recently been banned in both the EU and UK. At present, there is no direct replacement for ZnO, but rather a range of practices. These include a variety of nutritional and management changes, that may be variously applied according to the circumstances of each farm. This is prompting concern that by withdrawing ZnO, post-weaning diarrhoea may become more difficult to manage, with adverse consequences on piglet health and welfare. Despite the sector's best efforts, treatment will more likely need to rely on antibiotics to treat disease and manage diarrhoea. This, therefore, presents us with a conundrum: banning ZnO may possibly increase antibiotic resistance on farms, because farmers may need to use more antibiotics in practice, to treat sick piglets after weaning. These intended and unintended consequences of ZnO withdrawal are the focus of this proposal.In this study, we will work closely with producers over the withdrawal period to investigate the impact of ZnO withdrawal on piglet health and to identify measures that may help. In particular we are interested in the consequences of ZnO withdrawal on the levels of disease-causing bugs on farms and any changes in carriage of antibiotic resistance by pigs. We will do so by collecting dung samples from a small number of commercial herds across the UK and comparing samples from before and after the ZnO ban. We have already collected pre-ban samples from a number of UK commercial herds, in a precursor pilot project to this proposed study. Laboratory analysis of these dung samples will show which disease-causing bugs are present, and allow us to look for changes in the characteristics of these bugs and their association with disease, before and after the ZnO ban. Using genome sequencing technologies, we will look for antibiotic resistance markers, to see whether these all change after ZnO is withdrawn. Our findings will provide a 'barometer' of piglet health across UK farms during the transitional withdrawal period. We will also examine what differences are seen in the healthy gut microflora in pigs in the presence of ZnO and whether particular beneficial bacteria can be identified. We will investigate how we can exploit these differences to develop alternative feed supplements, such as "friendly bug" supplements that may help in the control of disease and improve piglet health.By providing evidence-based information, this project will help offset existing uncertainties and inform wider discussion as the sector adjusts to 'zero zinc.' This in turn would be expected to lead to the development of pig production systems that deal sustainably with the challenge of managing the post-weaned piglet.

在大多数国家，养殖猪通常在四周龄左右断奶。由于消化系统不成熟，仔猪特别容易出现肠道问题，并且特别容易出现断奶后腹泻的情况。断奶后腹泻会导致受影响的动物感到痛苦和不适，并可能导致死亡。康复的仔猪通常健康状况较差，生长速度减慢，影响福利和农场生产力。胃肠道疾病是目前英国和全球养猪系统可持续性面临的最重大挑战，影响着全球一半以上的养猪户，给该行业带来了巨大损失。直到最近，断奶后腹泻还可以通过在断奶后饲料中添加氧化锌 (ZnO) 来控制，从而减少疾病并改善仔猪的结局。然而，由于担心氧化锌会导致抗生素耐药性的发展，欧盟和英国最近已禁止预防性使用氧化锌。目前，还没有直接替代ZnO的方法，而是有一系列的做法。其中包括各种营养和管理方面的变化，可以根据每个农场的具体情况进行不同的应用。这引发了人们的担忧，即取消氧化锌后，断奶后腹泻可能会变得更难以控制，对仔猪的健康和福利产生不利影响。尽管该部门尽了最大努力，但治疗很可能需要依赖抗生素来治疗疾病和控制腹泻。因此，这给我们带来了一个难题：禁用氧化锌可能会增加农场的抗生素耐药性，因为农民在实践中可能需要使用更多的抗生素来治疗断奶后生病的仔猪。 ZnO 戒断的这些有意和无意的后果是本提案的重点。在这项研究中，我们将在戒断期间与生产者密切合作，调查 ZnO 戒断对仔猪健康的影响，并确定可能有帮助的措施。我们特别感兴趣的是氧化锌停用对农场致病菌水平的影响以及猪对抗生素耐药性的任何变化。我们将通过从英国各地的少量商业畜群收集粪便样本并比较氧化锌禁令前后的样本来做到这一点。在这项拟议研究的先行试点项目中，我们已经从许多英国商业牛群中收集了禁令前的样本。对这些粪便样本的实验室分析将显示存在哪些致病细菌，并使我们能够在氧化锌禁令之前和之后寻找这些细菌特征的变化及其与疾病的关联。利用基因组测序技术，我们将寻找抗生素耐药性标记，看看这些在ZnO被撤回后是否会发生变化。我们的研究结果将为英国农场在过渡停药期间仔猪健康状况提供一个“晴雨表”。我们还将研究在氧化锌存在下猪的健康肠道菌群有何差异，以及是否可以识别出特定的有益细菌。我们将研究如何利用这些差异来开发替代饲料补充剂，例如可能有助于控制疾病和改善仔猪健康的“友好昆虫”补充剂。通过提供基于证据的信息，该项目将有助于抵消现有的不确定性和随着该行业调整至“零锌”，为更广泛的讨论提供信息。这反过来又有望促进养猪生产系统的发展，可持续地应对断奶后仔猪管理的挑战。