Comparative study on hypocholesterolemic effect of Rhodopseudomonas palustris and Rhodobacter capsulatus on rats fed a high cholesterol diet

This comparative study was to investigate the hypocholesterolemic effects of dietary Rhodopseudomonas palustris and Rhodobacter capsulatus on rats fed a high cholesterol diet. Thirty male Wister-Imamichi rats were assigned to three groups and fed on either a high cholesterol diet, or a high cholesterol diet supplemented with 2.0% R. palustris or R. capsulatus for 4 weeks. Compared to the control diet, both of the R. palustris and R. capsulatus supplemented diets significantly reduced the serum cholesterol, triglycerides, low-density lipoprotein, very low density lipoprotein cholesterol and hepatic triglycerides, but increased hepatic cholesterol in rats. In addition, both of the R. palustris and R. capsulatus supplemented diets may reduce the risk of atherosclerosis, as the ratio of high density lipoprotein cholesterol to the total cholesterol was significantly higher than in the control group (P < 0.05). Both the R. palustris and R. capsulatus supplemented diets led to an increase in the serum palmitic acid, compared with the oleic acid and linoleic acid. No significant differences were postulated between the rats fed R. palustris and R. capsulatus supplemented diets during the 4 weeks of the experimental period. Thus, the results may suggest that both R. palustris and R. capsulatus can contribute significant health benefits and seems to be feasible to investigate in future research.