Abstract

The global shift toward antibiotic-free poultry production has created an urgent need for sustainable feed additives that promote gut health and productivity. This study aimed to develop and evaluate a novel double-layered microencapsulated phytosynbiotic (DMP) comprising Tiliacora triandra extract, probiotics, and cereal by-products using lyophilization. In Experiment 1, we investigated the effects of cell wall materials (corn, defatted rice bran, and wheat bran) and different particle sizes (0.6 and 1.0 mm) on the physicochemical characteristics and probiotic encapsulation efficiency. Results revealed that wheat bran, particularly at the smaller particle size of 0.6 mm, enhanced probiotic viability, probiotic stability under simulated gastrointestinal and thermal conditions, and nutrient retention. Compared with other materials, wheat bran also provided superior powder flowability, lower density, and favorable color attributes. In Experiment 2, we assessed the influence of probiotic strains (P. acidilactici, Lactiplantibacillus plantarum TISTR 926, and Streptococcus thermophilus TISTR 894) on functional properties of the DMP. All strains exhibited high encapsulation efficiency and stability during gastrointestinal simulation, thermal exposure, and storage. However, P. acidilactici had superior fermentation kinetics and produced greater levels of beneficial short-chain fatty acids, especially acetic and butyric acids. Antibacterial activity was strain-dependent, with notable inhibitory effects against Gram-positive pathogens, primarily through bacteriostatic mechanisms. Overall, these findings confirm that the developed DMP formulations effectively stabilize probiotics and bioactive phytochemicals, offering a promising strategy for enhancing gut health and performance in antibiotic-free broiler production systems.