Safety Evaluation of Lactobacillus casei C1 in Wistar Rats

Abstract

Nowadays, probiotics have been widely consumed as supplementary food for their health benefits. However, safety evaluation for many probiotic bacteria is still lacking. Furthermore, health benefits conferred by probiotics depend on the strains used in producing probiotic products. Therefore, it is important to examine oral toxicity of newly isolated Lactobacillus casei (Lb. casei) C1. A total of 32 Wistar (WIS) rats were divided into acute (single dose) and subacute oral toxicity (28-days repeated dose) groups. Rats in each group were further divided into control group which received phosphate buffer saline (PBS) orally and treatment group that was administered orally with Lb. casei C1 (1011 CFU/ml). For acute oral toxicity, treatment was performed on day-1 and the effects were monitored subsequently for 14 days.  For subacute oral toxicity, treatment was given daily for 28 days and the effects were observed throughout the experimental period. Body weight, food and water intake of the rats were recorded. Rats in acute and subscute groups were sacrificed on day-15and day-29, respectively. Serum was collected to determine the levels of total protein, malondialdehyde (MDA), alanine transaminase (ALT), aspartate transaminase (AST), lactate dehydrogenase (LDH) and creatinine. Organs were also harvested for histological examination. There were no significant differences (p>0.05) in body weight, food and water intake between the control and treated rats in acute oral toxicity group. There were also no significant differences in the blood cell count, levels of total protein, MDA, LDH and creatinine between the control and treated rats. Similar findings were recorded for the subacute oral toxicity group, except that the levels of ALT and AST which were significantly different (p<0.05). When observed under a light microscope, there were no morphological changes detected in the kidney, liver and ileum of treated rats as compared to control rats in both of the experimental groups. In conclusion, Lb. casei C1 exhibited no toxic effects in Wistar rats hence safe to be consumed orally.DOI : http://dx.doi.org./10.17576/JSKM-2018-1602-04