Encapsulated Bacillus sp. THPS1, a novel thermophilic probiotic, enhances productivity and metabolic health in laying hens

Encapsulated probiotics, sustainable alternatives to antibiotic growth promoters in poultry production, enhance productivity and physiological health. Comparative evidence on strain-specific encapsulated Bacillus probiotics and their combined effects on production performance, egg quality, metabolic indicators, and hematological profiles in laying hens is insufficient. This study evaluated three encapsulated Bacillus strains (THPS1, PWR01, and OYNH19) for sporulation, encapsulation, and spore release efficiencies. A feeding trial in laying hens supplemented with 1 × 10⁶ spores/g feed was conducted over 4 weeks. Production performance, egg quality traits, serum lipid profiles, stress hormone levels, and hematological parameters were assessed. Sporulation and encapsulation efficiencies were consistently exceeded 96 %, while spore release efficiency exhibited significant variation across strains. OYNH19 demonstrated lower release efficiency compared to THPS1 and PWR01 strains (p = 0.042). Dietary supplementation with THPS1 significantly enhanced feed conversion ratio (FCR) (0.23 ± 0.01), resulting in a 23 % reduction compared to the control and other probiotic treatments (p = 0.001). Notably, egg production rate and body weight (BW) remained unchanged. However, egg weight (EW) was exhibited a significant increase in the THPS1 group by week 4 (65.22 ± 4.67 g; p = 0.041), without any adverse effects on eggshell or internal quality traits. Furthermore, THPS1 supplementation was associated with reduced serum triglyceride concentrations and distinct multivariate clustering, indicating coordinated alterations in production, metabolic, and hematological variables. Overall, encapsulated Bacillus sp. THPS1 demonstrated superior efficacy in optimizing feed efficiency while maintaining physiological stability.