O'Connor A M, Denagamage T, Sargeant J M, Rajić A, McKean J
Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, South 16th Street, Ames, IA 50010, USA.
Prev Vet Med. 2008 Nov 17;87(3-4):213-28. doi: 10.1016/j.prevetmed.2008.06.017. Epub 2008 Jul 30.
This review summarizes evidence for associations between Salmonella prevalence in market-weight swine and changes in feeding management practices or feed characteristics. A systematic review of the topic was conducted with the goal of minimizing the impact of bias on the review conclusions. Potential interventions included feed withdrawal from swine prior to slaughter, feed acidification, heat treatment of feed, pelletized feed versus mash, course versus fine grind, and wet versus dry feeds. In the reviewed literature, Salmonella prevalence was measured either by culture or by the presence of antibodies to Salmonella. The evidentiary value of studies was assessed, and studies that failed to meet predetermined standards were excluded. 7694 potentially relevant references were identified by an extensive literature search; however, 2623 references that were not published in English were excluded, because funds for translation were not available. Of the remaining references, only 277 were considered relevant to the review topic by two independent reviewers, and assessed for methodological quality. During quality assessment, 233 references were excluded because they failed to report design features that limit the introduction of bias or were conducted in a non-target population such as gnotobiotic, neonatal, nursery, or recently weaned pigs and sows. Forty-four publications passed the quality assessment conducted by 2 independent reviewers, but only 15 of the 44 publications reported studies that tested hypotheses associated with feeding management practices and feed characteristics and Salmonella prevalence in market-weight swine. The most common study design was cross-sectional (7/15). The included studies failed to provide strong evidence of an association between any of the potential interventions and Salmonella prevalence, due to the potential for confounding, and the failure to document temporal association between the intervention and Salmonella prevalence. The strongest evidence of an association was found for feed form, i.e. the use of non-pelleted may be potential interventions associated with reduced Salmonella prevalence. The uncertainty is primarily based on studies containing moderate to low evidentiary value or insufficient numbers of tested individuals, resulting in a low degree of confidence that results could be extrapolated to the target population. Therefore, the conclusion of the review is that there should be a low level of comfort among qualified scientists that the claimed association between non-pelleted feed and reduced Salmonella prevalence is scientifically valid. There is no strong evidence regarding associations between presence of Salmonella and the other feed characteristics examined.
本综述总结了市场体重猪中沙门氏菌流行率与饲养管理实践或饲料特性变化之间关联的证据。针对该主题进行了系统综述，目的是尽量减少偏倚对综述结论的影响。潜在干预措施包括屠宰前对猪进行停饲、饲料酸化、饲料热处理、颗粒饲料与粉料、粗磨与细磨以及湿料与干料。在已审阅的文献中，沙门氏菌流行率通过培养或沙门氏菌抗体的存在来测定。评估了研究的证据价值，未达到预定标准的研究被排除。通过广泛的文献检索确定了7694篇潜在相关参考文献；然而，由于没有翻译资金，排除了2623篇非英文发表的参考文献。在其余参考文献中，只有277篇被两名独立审阅者认为与综述主题相关，并对方法学质量进行了评估。在质量评估期间，排除了233篇参考文献，因为它们未报告限制偏倚引入的设计特征，或者是在非目标群体（如无菌、新生、保育或刚断奶的猪和母猪）中进行的。44篇出版物通过了两名独立审阅者进行的质量评估，但在这44篇出版物中，只有15篇报告了测试与饲养管理实践、饲料特性以及市场体重猪中沙门氏菌流行率相关假设的研究。最常见的研究设计是横断面研究（7/15）。由于存在混杂因素，且未记录干预措施与沙门氏菌流行率之间的时间关联，纳入的研究未能提供任何潜在干预措施与沙门氏菌流行率之间存在关联的有力证据。发现饲料形式存在关联的最强证据，即使用非颗粒饲料可能是与降低沙门氏菌流行率相关的潜在干预措施。不确定性主要基于证据价值为中度至低度的研究或测试个体数量不足，导致对结果可外推至目标群体的信心程度较低。因此，综述的结论是，合格科学家对于非颗粒饲料与降低沙门氏菌流行率之间声称的关联在科学上有效的信心水平应该较低。关于沙门氏菌的存在与所研究的其他饲料特性之间的关联，没有有力证据。
