Propolis residue inclusion in the diet affects digestive enzyme activity in broiler chickens

This study investigated the effects of the inclusion of solid propolis residue (PR) from alcoholic propolis extraction in the diets of broiler chickens from 1 to 21-d of age on their performance, intestinal morphology, and digestive enzyme activity. 405 male chicks were distributed in a completely randomized design with five treatments (inclusion of 0, 1, 2, 3 and 4% PR in the diets), and three replications with 27 birds each. The birds were fed experimental diets from 1 to 21-d of age and basal diet from 22 to 42-d of age. Feed intake (from 1 to 21-d and 1 to 42-d of age) decreased linearly with increasing levels of PR inclusion (P < 0.05). Dietary inclusion of PR did not affect intestinal morphology at 7 and 21-d of age (P > 0.05). Pancreatic amylase activity presented a quadratic response at 7 and 21-d of age, with its lowest activity estimated at 2.45 and 1.91% PR inclusion, respectively. At 7-d of age, trypsin activity decreased linearly, whereas chymotrypsin activity varied quadratically, with its activity estimated at 2.06% PR inclusion. Intestinal maltase activity varied quadratically with lowest activity predicted at 1.57% PR inclusion at 21-d of age. The dietary inclusion of solid propolis residue of propolis decreases feed intake in broilers and modulates their intestinal and pancreatic enzyme activity.