Preliminary characterisation of Bacillus subtilis strain use as a dietary probiotic bio-additive in weaning piglet

Abstract

The aim of the study was to characterize the Bacillus subtilis ATCC 6051a strain, in order to establish its probiotic utility in piglet nutrition. The strain was assayed morphologically, culturally, biochemically, for hemolytic activity and enzymatically (amylase and protease). The identification and analysis of the biochemical characteristics was performed by catalase assay, API 50 CHB Biomerieux strips, apiweb API 50 CHB V 4.0 soft (B. subtilis very good identification, 99.4% ID) and ABIS online. The hemolytic activity was assayed on blood agar medium. The growth activity of strain was evaluated in two ways: static incubation (30 °C, 24 h, 1.36 x 108 CFU/ml) and under constant agitation (30 C, 24 h, 150 rpm, (1.6 x 109 CFU/ml). The strain is a Gram - positive and rodshaped bacteria, arranged in short chains or in small irregular pairs with ability to produce spores on nutrient medium. The endospores were central, paracentral and subterminal, which did not deform the vegetative cell. The strain growth was aerobic and was non - hemolytic. The enzymatic process was observed by appearance of distinct zones around strain colonies. In conclusion, the results suggested that the strain present probiotic traits and can be further assessed for other probiotic characters (resistance to pH 2.0, resistance to bile acids and salts, antibacterial activity, induction of local immune response etc.).

Keywords

• api 50 chb
• hemolytic activity
• enzymatic screening