Safety evaluation for multispecies probiotics in a 28-day feeding study in Sprague-Dawley rats

This experiment evaluated the 28-day feeding study in rats after they were continuously fed with multi-species probiotics dosages in the low-dosage, medium-dosage, and high-dosage groups: 2,000 mg/kg body weight (B.W.), 4,000 mg/kg B.W., and 6,000 mg/kg B.W., respectively, for 28 days as a reference for the safety of its repeated usage. Each group consisted of 10 male and 10 female Sprague-Dawley (SD) rats and the test substance was administered for 28 continuous days. After the experiment, the rats were sacrificed, and their blood and viscera were collected for haematological analysis, serum bio-chemical analysis, and pathological examination. The test results showed that, during the experiment, none of the tested rats exhibited abnormal clinical symptoms; the rats in all dosage groups gained weight normally. At the end of the test, the results of urological testing, haematological testing, and serum biochemical testing revealed no significant differences between the dosage groups and the control group. The results of the pathological dissection, the macroscopic inspection of pathological changes, and the histopathological inspection revealed no significant pathological changes related to the tested substance in the dosage groups and the control group.   Key words: Probiotics, Sprague-Dawley rat, haematological analysis, serum biochemical analysis, pathological examination.