Effects Of Mannose-oligosaccharide On Intestinal Morphology And Bacterial Community In Gastrointestinal Tract Of Broiler Chickens

The experiment was conducted to investigate the effects of mannose-oligosaccharide (MOS) on intestinal morphology and bacterial community in gastrointestinal tract of broiler chickens and to provide theoretical basis for the reasonable utilization and the feasibility of replacing antibiotics of mannose-oligosaccharide. The experiment included three parts:The first experiment was designed to preliminarily explore the effects of mannose-oligosaccharide (MOS) on growth performance of broilers. One hundred and ninety-two one-day-old AA broiler chickens were randomly allocated into two groups with four replicates of twenty-four birds per replicate. The diets were fed between 1 and 42 days of age. The birds were fed with basal diet (groupⅠ) and the same diet supplemented with MOS at the level of 0.2% at 1-21d and 0.1% at 22-42d (groupⅡ). The results showed that MOS supplementation in diet decreased the feed intake and body weight gain significantly from 1 to 21 d (P<0.01). There was no effect of MOS on feed conversion ratio. From 22 to 42 d, the birds fed the diet supplemented with MOS had lower feed intake than those fed the basal diet (P<0.05), while feed conversion ratio improved significantly (P<0.01). Through the whole trial period, MOS supplementation in diet improved the feed conversion ratio significantly (P<0.05).The second experiment was designed to study the effects of mannose-oligosaccharide on intestinal morphology in broilers. The results showed that, MOS tended to increase the villus height of duodenum through the whole trial period and that of jejunum at later period, while increased ileal villus height significantly at 22 and 42d (P<0.05). Compared to the control group, MOS significantly decreased the crypt depth of duodenum, jejunum and ileum at 1-21d (P<0.05). MOS increased the V/C ratio of duodenum significantly (P<0.05) and had the trend to increase the V/C ratio of jejunum and ileum through the whole trial.The third experiment was designed to study the effects of mannose-oligosaccharide on microflora in gastrointestinal tract of broilers. The results showed that the major species in gut were Lactobacilli, and each region of the gut developed its own unique microbial profile, and this community became more complex as the chickens grew older. The diversity of the bacterial community was richest in cecum, where the bacterial community at each age became lower in similarity as it approached to the distal gut. MOS enhanced the growth of Lactobacilli in the gut, while inhibited the growth of Clostridium to maintain gut health. It was also found that the highest similarity of the bacterial community in gizzard, duodenum, jejunum, ileum and cecum in the control group were 77%,68%,72%,49% and 63% respectively, while those in groupⅡwere 76%,84%,72%,49% and 63% respectively. The results demonstrated that chicken age had the most profound effect on these characteristics of the microbiota.