Previous animal and human studies have shown protective effects of Ca on the resistance to enteropathogenic
infections. Most interventions were performed with
calcium phosphate and little is known about the protective effect of other dietary sources of Ca. Therefore, we investigated the efficacy of several Ca
salts to enhance intestinal resistance to Salmonella enteritidis
infection. Rats (n 7-8 per group) were fed a high-fat, Western human-style, purified diet with a low Ca content (20 mmol
calcium phosphate/kg; negative control group) or the same diet supplemented with either (extra)
calcium phosphate, milk Ca,
calcium chloride or
calcium carbonate (total of 100 mmol Ca supplement/kg). Diets contained Cr-
EDTA for assessment of incremental changes in intestinal permeability. After an adaptation period of 2 weeks, animals were orally infected with S. enteritidis to mimic a human-relevant foodborne
infection. Ca supplement-induced changes on faecal lactobacilli and enterobacteria were studied before
infection. Changes in intestinal permeability were determined by measuring urinary Cr with time. Persistence of Salmonella was determined by studying faecal excretion of this pathogen in time. Overall, all Ca
salts increased resistance towards Salmonella. After
infection,
body weight gain and food intake were higher in the
calcium phosphate group.
Calcium phosphate and milk Ca decreased faecal enterobacteria before
infection. All Ca
salts decreased
infection-induced intestinal permeability and persistence of Salmonella.
Calcium phosphate, milk Ca,
calcium carbonate and
calcium chloride are able to enhance the intestinal resistance to Salmonella in rats.