EVALUATION OF DIETARY INFLUENCES ON ESCHERICHIA-COLI 0157-H7 SHEDDINGBY SHEEP

The effect of diet, an abrupt diet change, and fasting on the shedding of Escherichia coli O157:H7 was investigated with experimentally inoc ulated sheep as a ruminant model, Sheep were fed a grass hay diet (G), which was low in protein and digestible energy and high in fiber, or a mixture of corn and pelleted alfalfa (C), which was high in protein and digestible energy and low in fiber, After a single oral inoculatio n of E, coli O157:H7, all the animals shed fecal E, coli O157:H7, Howe ver, sheep that were fed G shed the bacterium almost twice as long as, and in larger numbers than, did sheep that were fed C, The number of culture-positive animals increased after the diet was abruptly changed from C to G and decreased with the opposite change (G to C), A 24-h f ast did not influence E, coli O157:H7 shedding, Horizontal transmissio n of infection between animals occurred, Recent shedding of E, coli O1 57:H7 did not affect recolonization with E, coli O157:H7, The findings presented in this study indicate that preharvest control of diet may reduce the risk of E, coli O157:H7-positive animals entering the food chain.