Safety Evaluation and antioxidant potential of new probiotic strain Bacillus subtilis (NMCC-path-14) in Balb/c mice by sub-acute repeated dose toxicity

Probiotics have recently gained significant interest for their possible therapeutic effects in treating numerous health conditions. Probiotics containing <i>Bacillus subtilis</i> have been shown to have several health benefits, most notably in preventing diarrhea and gastrointestinal problems. A novel probiotic strain, Bacillus subtilis (NMCC-path-14), isolated from the rumen of a Nilli Ravi Buffalo, was evaluated for 28-day repeated dose toxicity in Balb/c mice. The NMCC-path-14 in low dose (1 × 10⁸ CFU/ml) and high dose (1 × 10¹⁰ CFU/ml) was administered to the mice through gavage regularly. After 28 days of treatment, it was discovered that the no-observed-adverse-effect level (NOAEL) for NMCC-path-14 wasgreater than 1 × 10¹⁰ CFU/animal/day. This study also revealed no treatment-related changes in clinical parameters, body weight, gross pathology, or histology. Food consumption, hemoglobin, hematocrit, red blood cell counts, and colon length increased, while total/differential leukocyte count and platelets remained unchanged. The administration of NMCC-path-14 also resulted in decreased bilirubin and creatinine levels. Furthermore, NMCC-path-14 also displayed a promising antioxidant potential by increasing the antioxidant enzymes (GST, GSH, and CAT) and decreasing oxidant enzyme (MDA and NO) levels in vital organs like the liver, kidneys, spleen, and colon. TheNMCC-path-14also decreased the pathogenic bacterial population while increasing the beneficial population. Given the lack of adverse effects observed after NMCC-path-14 treatment, this strain is safe and must be considered as a potential probiotic in humans.