Microencapsulated phage composites with increased gastrointestinal stability for the oral treatment of colonization in chicken.

infection, one of the common epidemics in the livestock and poultry breeding industry, causes great economic losses worldwide. At present, antibiotics are the most commonly used treatment for infection, but the widespread use of antibiotics has increased drug resistance to . Phage therapy has gradually become an alternative method to control infection. However, phage, a specific virus that can infect bacteria, has poor stability and is prone to inactivation during treatment. Microencapsulated phage microspheres can effectively solve this problem. Accordingly, in this study, phages were microencapsulated, using the xanthan gum/sodium alginate/CaCl/chitooligosaccharides method, to improve their gastrointestinal stability. Furthermore, microencapsulated phages were evaluated for temperature and storage stability and therapeutic effect. Phage microspheres prepared with 1 g/100 mL xanthan gum, 2 g/100 mL sodium alginate, 2 g/100 mL CaCl, and 0.6 g/100 mL chitooligosaccharides were regular in shape and stable in the temperature range of 10-30°C. Also, microencapsulated phages showed significantly improved stability in the simulated gastric juice environment than the free phages ( < 0.05). In the simulated intestinal fluid, microencapsulated phages were completely released after 4 h. Moreover, microencapsulated phages showed good storage stability at 4°C. In the experiments detecting colonization in the intestinal tract of chicks, microencapsulated phages showed a better therapeutic effect than the free phages. In conclusion, microencapsulated phages exhibited significantly improved stability, gastric acid resistance, and thereby efficacy than the free phages. Microencapsulated phages can be potentially used as biological control agents against bacterial infections.