Microbiome of the gastrointestinal tract () has been identified as one of the crucial factors influencing the health and condition of domestic animals. The global poultry industry faces the challenge of understanding the complex relationship between gut microbiota composition and performance-related traits in birds. Considerable variation exists in the results of correlational studies using either 16S rRNA profiling or metagenomics to identify bacterial taxa associated with performance, productivity, or condition in poultry (e.g., body weight, growth rate, feeding efficiency, or egg yield). In this review, we survey the existing reports, discuss variation in research approaches, and identify bacterial taxa consistently linked to improved or deteriorated performance across individual poultry-focused studies. Our survey revealed high methodological heterogeneity, which was in contrast with vastly uniform focus of the research mainly on the domestic chicken () as a model. We also show that the bacterial taxa most frequently used in manipulative experiments and commercial probiotics intended for use in poultry (e.g., species of , or ) do not overlap with the bacteria consistently correlated with their improved performance ( Arthromitus, ). Our conclusions urge for increased methodological standardization of the veterinary research in this field. We highlight the need to bridge the gap between correlational results and experimental applications in animal science. To better understand causality in the observed relationships, future research should involve a broader range of host species that includes both agricultural and wild models, as well as a broader range of age groups.

中文翻译：

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肠道微生物群组成对家禽的生产性能、生产力和状况是否存在一致的影响？

胃肠道微生物组已被确定为影响家畜健康和状况的关键因素之一。全球家禽业面临着理解鸟类肠道微生物群组成与性能相关性状之间复杂关系的挑战。使用 16S rRNA 分析或宏基因组学来识别与家禽性能、生产力或状况（例如体重、生长速度、饲养效率或产蛋率）相关的细菌分类群的相关研究结果存在相当大的差异。在这篇综述中，我们调查了现有的报告，讨论了研究方法的变化，并确定了与个别家禽研究中性能改善或恶化一致相关的细菌分类群。我们的调查显示出高度的方法异质性，这与主要以家鸡为模型的研究重点非常一致形成鲜明对比。我们还表明，操作性实验中最常用的细菌分类群和用于家禽的商业益生菌（例如， 或 的物种）与与其改进性能一致相关的细菌（Arthromitus，）并不重叠。我们的结论敦促加强该领域兽医研究的方法标准化。我们强调需要弥合动物科学中相关结果和实验应用之间的差距。为了更好地理解观察到的关系中的因果关系，未来的研究应该涉及更广泛的宿主物种，包括农业和野生模式，以及更广泛的年龄组。