Protective effects of dietary lactulose and calcium phosphate against Salmonella infection

Background: Protection against intestinal infections by lactulose fermentation might be enhanced by calcium phosphate, due to the increased buffering capacity and/or inhibition of the cytotoxicity of luminal contents. Methods: SPF rats were fed a low-calcium control diet, a low-calcium/lactulose diet or a high-calcium/lactulose diet and orally infected with Salmonella enteritidis. Faeces and urine were sampled for microbiological and chemical analyses. Results: The lactulose-fed rats had a better colonization resistance. Translocation was reduced by dietary calcium, whereas lactulose was ineffective. In addition, calcium supplementation stimulated lactulose fermentation, reversed the lactulose-induced increase in cytotoxicity of faecal water and normalized growth and faecal consistency. Conclusion: The combination of dietary lactulose and calcium phosphate is protective against Salmonella infection.