Effect of dietary β1-4 mannobiose in the prevention of Salmonella enteritidis infection in broilers

1. This study investigated the effects of beta 1-4 Mannobiose (MNB)-supplemented feeds on the kinetics of Salmonella enterica serovar Enteritidis (SE) in broilers and the ensuing histopathological changes. D-Mannose (MAN) was used for comparison. The diets supplemented with MNB or MAN were fed during the first two weeks after hatching to investigate any protection against SE infection in growing birds and any immunomodulatory functions in the gut. 2. MNB-supplementation reduced SE organ colonisation, caecal carriage and faecal shedding in a time-dependent manner. The high concentrations and persistency of the SE-specific IgA response in those birds given rations supplemented with MNB or MAN were associated with a decline in SE shedding and caecal carriage in the later stages of infection. MNB was more effective against SE infection than MAN. 3. Histological examination of the caecal wall and caecal tonsils at 23 d post-infection indicated a lesser degree of intestinal pathology. An increased number of intra-epithelial mononuclear cells (mature lymphocytes and macrophages) in the lining epithelium of birds fed on the diet supplemented with MNB was accompanied by an increased number of lamina propria cells. 4. The present study indicates that feeding a diet supplemented with MNB during the first two weeks after hatching reduced susceptibility to SE infection. Supplementing the diet with MNB or MAN increased IgA production and improved SE clearance by acting as immunomodulatory agents that prevented intestinal pathology. Feeding a MNB-supplemented diet to broilers could be used as an alternative to antibiotics, because it has no adverse effects on mortality or weight gain.