In-vitro and preclinical testing of bacillus subtilis UBBS-14 probiotic in rats shows no toxicity

Probiotics made from Bacillus subtilis provide a wide spread of health benefits, particularly in the treatment of diarrhea and gastrointestinal problems. Herein, we employed in vitro and in vivo paradigms to assess the potential adverse effects and toxicity of B. subtilis UBBS-14.

According to Organization for Economic Co-operation and Development (OECD) 423 and 407 requirements, a preclinical investigation was conducted in male and female Sprague-Dawley rats. Acute toxicity was examined following a single peroral (PO) administration of 5,000 mg/kg body weight (bw) i.e. equivalent to 500 billion colony-forming units (CFU) per kg bw. Single administration of B. subtilis UBBS-14 showed no mortality or adverse effects until the 14-day observation period, indicating LD50 is >5,000 mg/kg bw.

Incubation of B. subtilis UBBS-14 with Caco2, HT29, and Raw 264.7 cell lines, showed no cytotoxic effects. This probiotic strain was also found responsive to the majority of antibiotics. For a 28-day repeated dose toxicity study, rats were administered 100, 500, and 1,000 mg/kg bw daily once (10, 50, and 100 billion CFU/kg bw/day, respectively) doses of B. subtilis UBBS-14. No notable changes were seen in the morphology, weight, and histopathology of the critical internal organs. The haematological, biochemical, electrolyte (sodium, potassium, chloride, and calcium), and urine analytical results were within the normal range and equivalent to the vehicle-treated group.

B. subtilis UBBS-14's no-observed-effect level (NOEL) was thus determined to be >1,000 mg/kg bw/day following a 28-day oral dosing.