Abstract:
This experiment aimed to evaluate the effects of protein extract and mannan-oligosaccharide (MOS) from yeast on growth performance, intestinal morphology, Ileal IgA producing cells and Salmonella contamination of broilers challenged with nalidixic acid resistance Salmonella enterica serovar Enteritidis (SE). Five hundred and seventy five, 1 day old, male Arbor Acres broiler chicks were allocated into 5 treatments (5 replicates of 23 chicks). The treatments were: T1) Commercial basal diet. T2) Commercial basal diet and challenged with SE. T3) Commercial basal diet supplemented with 2% yeast protein extract (in starter diets) and challenged with SE. T4) Commercial basal diet supplemented with 2%, 1% and 0.5% MOS (in starter, grower and finisher diets, respectively) and challenged with SE. and T5) Commercial basal diet supplemented both additives and challenged with SE. Quantitative and qualitative Salmonella examination in liver-spleen and ileo-cecal content were performed using microbiological assay. Intestinal morphology was analyzed by histopathological assay. The results showed that dietary inclusion of protein extract and MOS significantly improved average daily gain and FCR during the starter period. Dietary inclusion of protein extract and MOS significantly reduced populations of SE in both ileo-caecal content and liver spleen pools at day 15 of age. At day 22, the duodenal villus height of chicks receiving yeast protein was higher than those challenged with SE alone (P<0.05). In grower and finisher period, the yeast protein group and MOS group had greater Villus:Crypt (VC) ratio than other groups. For jejunal and ileal morphology at day 22 and 43, all of supplemented groups have VC ratio slightly better than positive control. Salmonella inoculation increase IgA producing cells in ileal mucosa and supplementation of both additives had no positive effect compare with positive control. It is concluded that yeast protein extract and MOS helped to ameliorate the adverse effect of SE resulting in the improved intestinal morphology and less contamination of SE in gut and liver spleen pools of chicks. There was no positive effect of both additives on IgA producing cells.
