中文摘要：引起人畜共患病的细菌，其抗生素耐药性不断增加，对饲养食用动物的农民以及食用受污染肉类导致食源性感染的消费者来说都是一个重大隐患。饲料中加入噬菌体可能有助于减少包括鸡和猪在内的动物的携带和感染。然而，困难在于如何在处理过程中，如在动物饲料造粒操作期间以及在噬菌体穿过酸性胃环境期间保护噬菌体免遭破坏。本研究使用同心喷嘴和商用封装设备生产核壳胶囊，将噬菌体配制到核壳内油包水微乳液中。一经动物下消化道（GI）中常见的局部环境pH变化触发，胶囊在10-30分钟内释放出被包裹的噬菌体。即使在pH为1的酸性条件下，噬菌体仍能保持稳定性。封装的噬菌体能够承受饲料颗粒挤压加工过程中常遇到的条件：95℃湿热应激，120秒。而相同条件下，游离噬菌体在15 s内失活。可见，将油包水乳化噬菌体包埋在核壳ph响应胶囊中，可显著提高噬菌体暴露于加工和环境应激时的生存能力，能满足动物饲料生产和生物防治应用所需的条件。本研究结果将有助于指导开发未来适用于动物生物防治的动物饲料中噬菌体制剂。
外文摘要：Increasing antibiotic resistance in bacteria that cause zoonotic infections is a major problem for farmers rearing animals for food as well as for consumers who eat the contaminated meat resulting in food-borne infections. Bacteriophages incorporated in animal feed may help reduce carriage and infections in animals including chickens and pigs. There are, however, unmet challenges in protecting phages from processing stresses e.g., during animal feed pelleting operations and during transit of phages through the acidic gastric environment. Core-shell capsules were produced using a concentric nozzle and commercially available encapsulation equipment to fabricate capsules with phages formulated in an oil-in-water microemulsion in the core. pH-responsive capsules released the encapsulated phage cargo within 10-30 min triggered by changes in local environmental pH typically found in the lower gastrointestinal (GI) tract of animals. Acid stability of phages exposed to pH values as low as pH 1 was demonstrated. Encapsulated phages were able to withstand exposure to 95 degrees C wet heat thermal stress for up to 120 s, conditions typically encountered during feed pellet extrusion processing. Free phages were inactivated within 15 s under these conditions. The present study demonstrates that encapsulation of bacteriophages in core-shell pH-responsive capsules with water-in-oil emulsified phages in the core significantly improves phage viability upon exposure to processing and environmental stresses that require consideration during production of animal feed and application in animals for biocontrol. The results from this study should help guide future development of phage formulations suitable for use in animal feed for animal biocontrol applications.
外文关键词：antibiotic resistance；animal feed；bacteriophages；biocontrol；controlled release；core-shell capsules；microbiome engineering
作者：Richards, K；Malik, DJ
作者单位：Loughborough Univ
期刊名称：VIRUSES-BASEL
期刊影响因子：3.816
出版年份：2021
出版刊次：6
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