National Institute for Public Health and the Environment (RIVM), Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Utrecht University, the Netherlands.
Istituto Zooprofilattico Sperimentale delle Venezie, Legnaro, Italy.
Poult Sci. 2020 Feb;99(2):763-771. doi: 10.1016/j.psj.2019.10.027. Epub 2019 Dec 6.
Suboptimal animal welfare may affect natural immunity, rendering animals more susceptible to environmentally conditioned diseases, including those requiring antimicrobial treatment, which may promote antimicrobial resistance (AMR) in bacterial populations. Herewith, we tested the hypothesis that conventionally raised turkeys have higher levels of AMR in indicator Escherichia coli bacteria, but lower levels of natural immunity, as compared to turkeys reared under organic conditions. Litter and serum samples were collected from 28 conventional and 4 organic turkey farms: E. coli isolates from litter were tested for resistance to 14 antimicrobials, while 3 parameters of natural immunity (i.e., lysozyme, hemolytic complement levels, and serum bactericidal activity) were assessed in the sera. Resistant E. coli isolates were identified in both conventional and organic farms but generally more frequently in conventional farms. High rates of resistance to ampicillin (96%), tetracycline (95%), streptomycin (82%), sulfamethoxazole (80%), ciprofloxacin (73%), and trimethoprim (71%), as well as high rates of multiresistance, were observed in conventional farms. Organically raised turkeys had significantly higher levels of lysozyme and serum bactericidal activity than conventional turkeys, and these levels were also higher in turkeys housed in farms where AMR frequency was lower. Findings support the hypothesis that conventional farming conditions may affect turkeys' natural immunity, rendering the animals more susceptible to environmentally conditioned diseases requiring antimicrobial treatment, which would in turn promote AMR. Reducing AMR in turkey farming is therefore more likely to be successful when considering animal welfare as an option to reduce the need of antimicrobial use.
动物福利不佳可能会影响其自然免疫力，使动物更容易感染环境条件性疾病，包括需要抗菌治疗的疾病，这可能会促进细菌种群中的抗生素耐药性（AMR）。在此，我们检验了一个假设，即与在有机条件下饲养的火鸡相比，常规饲养的火鸡指示性大肠杆菌中的 AMR 水平更高，但自然免疫力水平更低。从 28 个常规和 4 个有机火鸡养殖场采集垫料和血清样本：从垫料中分离出的大肠杆菌对 14 种抗生素的耐药性进行了测试，而血清中的 3 种自然免疫参数（即溶菌酶、溶血补体水平和血清杀菌活性）进行了评估。在常规和有机农场均分离到耐药大肠杆菌，但在常规农场更为常见。常规农场中观察到对氨苄西林（96%）、四环素（95%）、链霉素（82%）、磺胺甲恶唑（80%）、环丙沙星（73%）和甲氧苄啶（71%）的耐药率较高，并且多耐药率也较高。有机饲养的火鸡的溶菌酶和血清杀菌活性水平明显高于常规饲养的火鸡，而在 AMR 频率较低的农场中饲养的火鸡的这些水平也更高。研究结果支持了这样一种假设，即常规养殖条件可能会影响火鸡的自然免疫力，使动物更容易感染需要抗菌治疗的环境条件性疾病，这反过来又会促进 AMR。因此，在考虑将动物福利作为减少抗生素使用需求的一种选择来减少 AMR 时，火鸡养殖中的 AMR 减少更有可能取得成功。
