Probiotic applications of bifidobacteria in poultry: administration methods and microencapsulation techniques.

The search for sustainable alternatives to antibiotic growth promoters in poultry production has intensified in recent years, driven by global concerns over antimicrobial resistance and consumer demand for safer food systems. Among the probiotic candidates investigated, Bifidobacterium spp. stand out for their well-documented safety, immunomodulatory properties, and ability to enhance gut health. This review provides a comprehensive analysis of the biological roles, delivery strategies, and microencapsulation techniques for Bifidobacterium spp. as probiotics in poultry. Bifidobacteria contribute to poultry health by modulating the gut microbiota, improving intestinal morphology and digestive enzyme activity, and regulating immune responses through cytokine balance and epithelial barrier reinforcement. However, their strict anaerobic metabolism and sensitivity to gastric acid and processing conditions limit their viability during conventional administration. To address these challenges, we examine various administration routes, including oral, in ovo, spray/litter, and cloacal methods, highlighting their practical advantages and constraints. Special attention is given to microencapsulation technologies, such as spray drying, freeze drying, spray chilling, extrusion, and emulsion, which protect bifidobacteria from environmental stress and enhance their delivery to target intestinal sites. By integrating recent advances in biotechnology and delivery systems, this review underscores the potential of Bifidobacterium spp. as functional feed additives in antibiotic-free poultry production. Tailoring encapsulation materials and administration routes to match specific production goals is key to maximizing probiotic efficacy. Continued research on strain performance under commercial conditions will be essential to facilitate their large-scale application in sustainable poultry farming.