Bacillus aryabhattai CKNJh11 as a promising probiotic improves growth performance and egg quality in laying hens.

This study aimed to identify probiotic candidates to enhance egg quality in laying hens by isolating and characterizing Bacillus spp. from various local environmental sources, including crustacean guts such as mud crab (Scylla serrata), blue crab (Portunus pelagicus), and banana shrimp (Penaeus merguiensis) from the coastal areas of the Gulf of Thailand and Andaman Sea, shrimp pond sludge, hot spring soil and chicken feces. Identification was carried using biochemical tests, evaluation probiotic properties, and 16S rRNA sequencing methods. Biochemical tests revealed that all 11 isolated strains had characteristics consistent with Bacillus spp. Six of these strains exhibited high spore efficiency, including CPPES01T2 (74.67%), CKNJh11 (80.33%), OYNH31 (82.07%), and THPS1 (71.42%). Strains CPPES01T2 and CKNJh11 were sensitive to ampicillin (10 µg/disc), amoxicillin (30 µg/disc), cloxacillin (1 µg/disc), tetracycline (30 µg/disc), chloramphenicol (30 µg/disc), and kanamycin (30 µg/disc). Strains CPPES01T2 showed tolerance to heat, while strains CPPES01T2, CKNJh11, and THPS1 demonstrated no hemolytic activity. Furthermore, CKNJh11 was selected for developing a supplementary feed for laying hens and the 16 S rRNA sequencing identified strain CKNJh11 as Bacillus aryabhattai which exhibited high resistance to artificial gastric juice and bile salts. For 6 weeks study, resulting in an increase in weight gain and eggshell weight of chickens (p < 0.05). The findings from this study suggest that B. aryabhattai can be a promising spore-forming probiotic bacteria by dietary supplementation with respect to hen performance, egg quality or further development in laying hen production.