Effect of Intestinal Microflora on Iron and Zinc Metabolism, and on Activities of Metalloenzymes in Rats

The effect of intestinal microflora on the absorption, excretion and retention of iron and zinc and on the activities of metalloenzymes such as alkaline phosphatase, catalase and xanthine oxidase in organs was investigated. Weanling germfree and conventional rats were fed a steam-sterilized semipurified diet until 90 days of age. Balance studies were then carried out for 10 days. In the second experiment, weanling germfree and conventional rats were maintained as above until 100 days of age, and the metalloenzymes were determined in serum, liver and kidneys. Germfree status decreased the apparent absorption and net retention of iron as compared to conventional status, whereas it had no significant effect on the absorption and retention of zinc. The results also indicate a higher total femur zinc per 100 g body weight in germfree rats, but the concentrations in liver and kidneys in germfree and conventional rats were similar. Hepatic xanthine oxidase activity was lower in germfree rats. The results also indicate that the absence of a viable intestinal microflora had no substantial effect on the serum, liver and kidney alkaline phosphatase activity, or on the liver and kidney catalase activity.