Effects of Probiotics on the Expression of Cathelicidins in Response to Stimulation by Lipopolysaccharides in the Proventriculus and Cecum of Broiler Chicks.

The aim of this study was to determine whether probiotic-feeding affected the expression of cathelicidins (), a major family of antimicrobial peptides, in response to lipopolysaccharides (LPS) challenge in the proventriculus and cecum of broiler chicks. One-day-old male Chunky broiler chicks were fed with or without 0.4% probiotics for 7 days (P-group and non-P-group, respectively). Then, they were orally challenged with no LPS (0-LPS), 1 g LPS (1-LPS), or 100 g LPS (100-LPS) (=5 in all groups) in Experiment 1, and with no LPS or 1 g LPS (=6 in all groups) in Experiment 2. Five hours after LPS challenge, the proventriculi and ceca were collected to analyze expression. Expression of was examined at first by reverse transcription-polymerase chain reaction (RT-PCR) using the 0-LPS chicks of non-P-group. The differences in expression upon probiotics-feeding and LPS were analyzed by real time-PCR. All four ( and ) were expressed in the proventriculus and cecum of chicks. In the proventriculus, the expression of after LPS challenge did not show significant differences between non-P and P-groups in Experiment 1 and 2. In the cecum, the interactions of the effects of probiotics and LPS on the expression of in Experiment 1 and and in Experiment 2 were significant, and their expression in 1-LPS chicks was higher in P-group than in non-P-group. However, and did not show any significant differences between non-P- and P-groups challenged with LPS. These results suggest that probiotics-feeding may stimulate the immunodefense system mediated by and possibly against infection by Gram-negative bacteria in the cecum.