Increased survival from acute Salmonella gallinarum infection in chicks given diets with high levels of some forms of iron.

Amounts exceeding 100 ppm of extra dietary iron as the ferric salts of ethylenediaminetetra-acetic acid (FeE) or nitrilotri-acetic acid (FeN) produced highly significant increases in survival among chicks infected with 10(6.4) living Salmonella gallinarum strain 9. Additional dietary iron (400 ppm) as the sulphate or chloride salts (or as ferric fructose) lacked activity comparable with FeE or FeN except when 0.2 per cent of NaE was also present in the diet. FeE iron (600 ppm) also diminished the severity of several of the pathological reactions which occur in chicks during the acute stage of experimental fowl typhoid. The enhanced survival and decreased severity of the pathological changes in infected chicks were associated with large reductions in the numbers of viable salmonellae in the spleen at the height of the acute infection.