Hypocholesterolemic effect of phototrophic bacterial cells in rats

The effect of diets containing the cells of a phototrophic bacteria (PTB). Rhodopseudomonas capsulata, on lipid metabolism was examined in the serum and liver of rats. Three groups of rats, 5 animals per group, were fed either a diet containing 0.2 or 2.0% PTB cells or a casein-based control diet. Each diet contained 1% cholesterol (CHOL). While serum glucose levels were not significantly different between the control and the PTB groups, total CHOL and triacylglycerol (TG) in the serum were significantly lower in the PTB groups than in the control group (p less than 0.01). The ratio of serum HDL-CHOL to total serum CHOL was significantly higher in the PTB groups than in the control group (p less than 0.01). The 2.0% PTB group had lower hepatic TG (p less than 0.05) but higher hepatic CHOL (p less than 0.05) than did the control group. These results indicate that PTB cells contain a factor or factors which affect hepatic metabolism or secretion of CHOL.