In vivo and in vitro assessment of commercial probiotic and organic acid feed additives in broilers challenged with Campylobacter coli

Campylobacter is a major foodborne pathogen associated with the consumption or handling of raw or undercooked poultry meat. In vitro and in vivo experiments were conducted to evaluate the effectiveness of commercial probiotic and organic acid (OA) feed additives for the reduction of Campylobacter coli. Supernatants from 4 probiotic strains were cocultured with C. coli at different dilutions. Probiotic supernatants decreased (P < 0.05) the in vitro proliferation of C. coli at 1:1 supernatant: pathogen dilution for Enterococcus faecium, Bifidobacterium animalis, and Pediococcus acidilactici and 5:1 dilution for Lactobacillus reuteri. Different concentrations of the OA were co-cultured with C. coli in vitro. Organic acid concentration of 0.08% significantly decreased the in vitro proliferation of C. coli (P < 0.05). For the in vivo experiment, 480 Cobb-500 broiler chicks were randomly assigned to 4 treatments: control (basal diet), probiotic (0.5 kg/ton), OA (0.5 kg/ton), or probiotic 1 OA (probiotic at 0.5 kg/ton from 0 to 28 D of age and OA 0.5 kg/ton from 28 to 42 D of age). Birds were challenged with 1 x 10(8) CFU/bird of C. coli gentamicin-resistant strain on 14 D of age. At 42 D of age, the combined treatment (probiotic 1 OA) had a nonsignificant 1.2 log reduction in C. coli load in ceca when compared with the positive control treatment (P = 0.08). The probiotic and OA products reduced (P < 0.05) the in vitro proliferation of Campylobacter. However, none of the treatments altered the Campylobacter load in ceca or on carcass at 42 D of age.