Evaluation of selected probiotic and prebiotic candidates on the control of Salmonella in chicks and poults.

摘要

Many of the more than 200 pathogenic serovars of the genus Salmonella are able to colonize the gastrointestinal tract of poultry. Because Salmonella is one of the most important agents involved with human foodborne infections, practical solutions to reduce its transmission are important for commercial poultry production. A series of experiments were conducted to evaluate the ability of prebiotics and probiotic cultures to reduce Salmonella spp. in chicks and poults. In the first experiment, repeated in three trials, chicks and poults were randomly assigned to treatment groups, challenged via oral gavage with Salmonella enterica serovar Heidelberg (SH) and treated one hour following challenge with a lactic acid bacteria probiotic via oral gavage. In all trials, the probiotic culture significantly reduced the incidence of SH in cecal tonsils of chicks and poults as compared to controls 24 and 72 hours following treatment. In the second experiment, repeated in three trials, the objective was to evaluate the effect of dietary Aspergillus meal (AM) prebiotic at a concentration of 0.2%, against horizontal transmission of Salmonella enterica serovar Enteritidis (SE) and Salmonella enterica serovar Typhimurium (ST) infection in poults and chicks, respectively. A significant reduction of SE cecal tonsil colonization was observed in poults that received dietary AM when compared with controls at all points of evaluation (p 0.05). The dietary AM significantly reduced organ invasion and cecal tonsils colonization of ST in chicks compared with non-treated control chicks. The last set of experiments consisted of 3 in vitro crop assay experiments and 2 independent in vivo trials. In the crop assay experiments, 0.2% chitosan significantly reduced total colony forming units (cfu) of ST at 0.5 or 6 hours post-treatment compared with controls (P 0.05). In the in vivo trials, day-of-hatch broiler chicks were challenged with ST, held in chick boxes for 1 h and randomly assigned to untreated control diet or dietary treatment with 0.2% chitosan. After 24 h, 0.2% dietary chitosan significantly reduced total cfu/g of recovered ST from the ceca in both experiments.