Growth Inhibition of Rats Fed Raw Navy Beans (Phaseolus vulgaris)

Abstract

Growth inhibition of rats fed raw navy beans and the action of antibiotics in overcoming it were investigated. The growth inhibitory action of a navy bean fraction isolated by sodium chloride extraction and precipitation by 0.75 ammonium sulfate saturation was also studied. More nitrogen and more of 5 amino acids studied were excreted in the feces of rats fed raw navy beans than in the feces of rats fed heated beans. Nitrogen and amino acid retention in the animals was increased by feeding antibiotics. The intestinal contents of rats fed raw navy beans contained more insoluble nitrogen, protein nitrogen and amino nitrogen and these were not changed by supplementation with antibiotics. Proteolytic activity in the intestine of animals receiving raw navy beans was similar to that of those receiving heated navy beans. Increased insoluble matter and proteolytic activity in the cecum and increased size of the cecum of rats receiving antibiotics suggest that the site of antibiotic action may be the cecum. No significant effect on nitrogen or amino acid absorption due to the inclusion of the navy bean fraction in the diet was observed. Growth inhibition of rats fed raw navy beans may, in part, be the result of endogenous loss of nitrogen and impaired absorption of amino acids.