Comparison of effects of live‐ and dead cell from potential probiotic lactic acid bacteria

Abstract

Lactic acid bacteria (LAB) are beneficial bacteria that have multiple potential health effects, including blocking gastroenteric pathogens, improving microbial balance, stopping intestinal dysfunction, and lowering cholesterol. In general, many these effects have been reported in live‐LAB. But nowadays it is trend that study for effects of killed‐LAB is increased. So we performed a comparative study for effects of live‐ and killed‐LAB such as lowering serum cholesterol, blocking microbial harmful enzyme activity, and anti‐bacterial effect. For this study, cultured supplements of LAB are used as live‐LAB and sonicated them are used as killed‐LAB. And these LAB were orally administered to Sprague‐Dawley male rats every day for 2 weeks along with a diet containing a high cholesterol. As a result, both the live‐ and killed‐LAB were found to reduce serum total cholesterol and LDL level, significantly (p<0.05). Killed‐LAB particularly increased HDL level by 10% compared to live‐LAB. Also, both the LAB inhibited the growth of penicillin‐resistant Staphylococcus aureus. These results showed that killed‐LAB exhibited the probiotic effects as well as live‐LAB, but effects of live‐LAB were generally better than those of killed‐LAB. In addition, live‐LAB decreased the tryptophanase activity by about 40%, and increased fecal water content and LAB levels. However, these effects were not observed in killed‐LAB.