The in vivo assessment of safety and gastrointestinal survival of an orally administered novel probiotic, Propionibacterium jensenii 702, in a male Wistar rat model

This study aimed to evaluate in vivo gastrointestinal survival and safety of orally administered probiotic bacterium, Propionibacterium jensenii 702, using a male Wistar rat model. A high dose of 10¹⁰ cfu/rat/day of P. jensenii 702 was fed to each rat for 81 days. The repeated dose toxicity and translocation of P. jensenii 702 into rat tissues were evaluated, along with the rat faecal β-glucuronidase activities and dairy propionibacteria counts. Results showed that P. jensenii 702 had no adverse effect on general health status, body weight gain, visceral organs and faecal β-glucuronidase activities. No viable cells of P. jensenii 702 were recovered from blood and tissue samples (mesenteric lymph nodes, liver and spleen) of rats, and no treatment-associated illness or death was observed. Faecal dairy propionibacteria counts reached 10⁸ cfu/g after 36 days treatment and remained between 10⁸–10⁹ cfu/g till the end of 81 days treatment. The results indicate that P. jensenii 702 was able to survive the in vivo gastrointestinal tract transit of rats, with no adverse affects on the animals. However, further human clinical trials are required before strain P. jensenii 702 could be incorporated into food for human consumption as probiotics.