Microencapsulation of a novel Bacteroides thetaiotaomicron strain: a promising strategy to fortify intestinal barrier fortification in weaned pig model

ABSTRACT Porcine Bacteroides thetaiotaomicron LYH5 demonstrated in vitro antimicrobial activity, suggesting probiotic potential. Due to poor gastric juice tolerance, LYH5 was encapsulated via extrusion using sodium alginate (SA) and gellan gum. Box-Behnken design optimization yielded optimal parameters: SA 1.5%, gellan gum 0.4%, CaCl₂ 0.9%, bacteria:glue ratio 1:4, achieving an encapsulation rate of 84.22±0.17%. Its effect on weaned piglet intestinal health was evaluated using 78 piglets (7.69±0.52 kg) randomly assigned to 4 groups for 40 days: CON (control), T (basal diet + LYH5 live bacteria, 1×10¹⁰ CFU/mL), TJ (basal diet + LYH5 microcapsules, 1×10¹⁰ CFU/mL, J (basal diet + empty capsules). The results of this experiment showed that compared with the control group, LYH5 microcapsule can improve the intestinal barrier function without affecting the growth performance of piglets, and provide ideas and references for the development of human next-generation probiotics (NGP). IMPORTANCE This study addresses the key bottleneck of poor gastric acid tolerance of probiotics via microencapsulation and provides a practical reference for the development of human next-generation probiotics.