The effects of grain and carboh ydrase enzyme supplementation were investigated on digestive physiology of chickens. A total of 625 one - day - old chicks (Ross 308) were randomly assigned to five treatments in a completely randomized design. Treatments included two different types of grains (wheat, and barley) with or without a multi - carbohydrase supplement. A corn - based diet was also considered to serve as a control . Feeding barley - based diet with multi - carbohydrase led to higher feed intake ( P < 0.01) than those fed corn - and wheat - based d iets. Birds fed on barley and wheat diets had lower weight gain despite a higher feed conversion ratio ( P < 0.01) . Total count and number of different type of bacteria including Gram - negative , E. coli , and Clostridia increased after feeding wheat and barle y but the number of Lactobacilli and Bifidobacteria decreased ( P < 0.01). Feeding barley and wheat diets reduced villus height in different parts of the small intestine when compared to those fed on a corn diet. However, enzyme supplementation of barley an d wheat diets improved weight gain and feed conversion ratio and resulted in reduced number of E. coli and Clostridia and increased number of Lactobacilli and Bifidobacteria, and also restored the negative effects on intestinal villi height ( P < 0.01 ) . The activities of pancreatic α - amylase and lipase were ( P < 0.01) increased in chickens fed wheat and barley diets when compared to the control fed on a corn diet . Enzyme supplementation reduced t he activities of pancreatic α - amylase and lipase ( P < 0.01) . In conclusion, various dietary non - starch polysaccharides without enzyme supplementation have an adverse effect on digesta viscosity, ileal microflora , villi morphology, and pancreatic enzyme activity.
