A natural carbohydrate fraction Actigen™ from Saccharomyces cerevisiae cell wall: effects on goblet cells, gut morphology and performance of broiler chickens

A study was conducted to evaluate a natural carbohydrate fraction (NCF) derived from mannan oligosaccharide in feed on growth performance, intestinal morphology and goblet cell number and area of male broilers. Dietary treatments included: 1) control diet (antibiotic and NCF free), 2) NCF at 200g/t, 3) NCF at 400g/t, and 4) NCF 800g/t. Birds were placed into 12 replicate pens/treatment (5 birds/pen). Body weight and feed intake were recorded weekly to day 42. At this time a 2.5cm section of jejunum and duodenum were excised post mortem for morphological analysis. Birds fed 200g/t and 800g/t NCF were significantly (P<0.01) heavier from day 14 onwards than the control birds. Feed intake was significantly increased for birds fed 200g/t NCF over the control in weeks 3 and 5 (P<0.05). Diet including 200g/t and 800g/t of NCF significantly decreased the FCR over the control in the first phase (1-14 days) (P<0.01), in the second phase all inclusion levels of NCF decreased FCR (P<0.05). NCF had no significant effect on villus height, villus width, crypt depth or villus to crypt ratio in either duodenum or jejunum. NCF did not significantly affect goblet cell area or goblet cell number in the duodenum, however in the jejunum 800g/t NCF significantly (P<0.05) increased goblet cell area over the control. In conclusion under the conditions of this trial NCF showed a positive effect on performance in the starter and grower phases, and increased goblet cell area in the jejunum, suggesting higher levels of mucin production. This indicated that the performance benefit of NCF could be age-dependent with younger birds responding more than the older ones. In the conditions of the poultry research unit, there were no additional benefits to performance when feeding NCF for a longer period (post 4 weeks), however it is postulated that birds fed NCF would have greater defence to pathogenic challenge through increased storage capacity of mucin.