Effect of lactose administration in drinking water prior to and during feed withdrawal on Salmonella recovery from broiler crops and ceca

Abstract

Salmonella contamination of the chicken crop has been reported to increase markedly and significantly during feed withdrawal, probably due to coprophagy, and may contribute to carcass contamination at processing. The effect of prolonged lactose administration (2.5%) in the drinking water on the incidence of Salmonella recovery from broiler crops or ceca was evaluated in seven experiments. In these experiments, all or a percentage (providing seeders and contacts) of 7-wk-old broilers were challenged with approximately 1 x 108 cfu Salmonella enteritidis and provided lactose for 5 or 11 d prior to and during an 18 or 24 h feed withdrawal period. A small but significant lactose-mediated reduction in Salmonella contamination of crops was observed in one of two identical experiments with 18 h feed withdrawal. Extending the feed withdrawal period to 24 h did not improve the ability of lactose to affect Salmonella recovery from crops or ceca. Similarly, lactose did not affect Salmonella recovery when the percentage of birds challenged was reduced to 3 out of 16 and Salmonella recovery from crops or ceca of unchallenged, contact broilers was measured. Extending the duration of exposure to 2.5% lactose in the drinking water from 5 to 11 d did not improve the ability of lactose to affect Salmonella recovery. Taken together, these data suggest that provision of 2.5% lactose in the drinking water during the last 5 to 11 d of growout prior to slaughter will not be useful in an integrated Salmonella control program under commercial conditions.