Hu Yan, Wang Laidi, Shao Dan, Wang Qiang, Wu Yuanyuan, Han Yanming, Shi Shourong
Poultry Institute, Chinese Academy of Agriculture Sciences, Yangzhou, China.
Center of Effective Evaluation of Feed and Feed Additive, Poultry Institute, Ministry of Agriculture, Yangzhou, China.
Front Microbiol. 2020 Jan 14;10:2948. doi: 10.3389/fmicb.2019.02948. eCollection 2019.
Understanding the differences in microbial communities shaped by different food selective forces, especially during early post-hatch period, is critical to gain insight into how to select, evaluate, and improve antibiotic growth promoters (AGPs) alternatives in food animals. As a model system, commercial diet-administered OAs (DOAs) and water-administered OAs (WOAs) were used separately or in combination as Virginiamycin alternatives for broiler feeding during two growth phases: 1-21 days and 22-42 days. Among these three OA-treated groups, the DOA group was most similar to the AGP group in the composition and the proportion of these dominant bacterial communities at the level of phylum, family, and genus in cecal chyme of broilers. Sub-therapeutic Virginiamycin decreased the richness, homogenization, and species diversity of gut microbiota, especially in the early growth stage from days 1 to 21. Among these three OA supplementation schemes, it was clear that DOA supplementation was more likely to increase or maintain the richness, homogenization, species diversity, and predicted gene functions of cecal microbiota in treated broilers than either no supplementation or AGP supplementation during two experimental stages. The interference of DOA treatment with early colonization of probiotics and pathogens in broiler cecum was the most similar to AGP treatment, and OAs did not cause the occurrence of Virginiamycin-resistant strains of at the end of this trial. In terms of the predicted gene functions of the microbiota, AGP and DOA treatments provided a similar selective force for microbial metabolism functions in the cecum of broiler chickens, especially in the early growth stage. Noticeably, the relative abundance of some microbiome that was modified by Virginiamycin or DOA supplementation was significantly correlated with body weight gain and KEGG pathway analysis-annotated gene functions such as replication and repair, translation, nucleotide metabolism, and so on. With the comprehensive analysis of these results and practical application, shortened DOA supplementation, after optimization of the amount of addition, would be a suitable alternative to sub-therapeutic Virginiamycin. It was suggested that the programed intestinal microecology under such early selection forces and the effective addition time may be the key elements to focus on the designed alternate strategies of AGPs in food animals.
了解由不同食物选择力塑造的微生物群落差异，尤其是在孵化后早期，对于深入了解如何选择、评估和改进食用动物的抗生素生长促进剂（AGP）替代品至关重要。作为一个模型系统，在两个生长阶段（1 - 21天和22 - 42天），分别或联合使用商业日粮添加有机酸（DOA）和饮水添加有机酸（WOA）作为维吉尼亚霉素的替代品用于肉鸡饲养。在这三个有机酸处理组中，DOA组在肉鸡盲肠食糜的门、科和属水平上，这些优势细菌群落的组成和比例与AGP组最为相似。亚治疗剂量的维吉尼亚霉素降低了肠道微生物群的丰富度、均匀度和物种多样性，尤其是在1至21天的早期生长阶段。在这三种有机酸添加方案中，很明显，在两个实验阶段，与不添加或添加AGP相比，添加DOA更有可能增加或维持经处理肉鸡盲肠微生物群的丰富度、均匀度、物种多样性和预测的基因功能。DOA处理对肉鸡盲肠中益生菌和病原体早期定殖的干扰与AGP处理最为相似，并且在试验结束时有机酸没有导致维吉尼亚霉素耐药菌株的出现。就微生物群的预测基因功能而言，AGP和DOA处理对肉鸡盲肠中的微生物代谢功能提供了相似的选择力，尤其是在早期生长阶段。值得注意的是，一些经维吉尼亚霉素或DOA添加修饰的微生物群落的相对丰度与体重增加以及KEGG通路分析注释的基因功能（如复制和修复、翻译、核苷酸代谢等）显著相关。综合分析这些结果和实际应用，在优化添加量后缩短DOA添加时间将是亚治疗剂量维吉尼亚霉素的合适替代品。建议在这种早期选择力和有效添加时间下的程序化肠道微生态可能是关注食用动物AGP设计替代策略的关键要素。
