A dose-response study to evaluate the effects of pH-stable β-mannanase derived from Trichoderma citrinoviride on growth performance, nutrient retention, and intestine morphology in broiler chickens

The objective of this trial was to determine the optimal supplementation level of β-mannanase preparation enzyme from Trichoderma citrinoviride on growth performance, apparent total tract retention of nutrients and gut health of broiler chickens. A total of 600 broiler chickens (Ross 308) were randomly allotted to four treatments on the basis of similar body weight. The dietary treatments included a corn soybean-based diet supplemented with 0 (control), 1200, 2400, or 4800 MNU/kg β-mannanase preparation. The experimental diets were fed in crumbles in phase 1 (1 to 14 days) and pellets in phase 2 (15 to 35 days). The linear and quadratic contrasts were used to compare effects of increasing dietary β-mannanase preparation levels. The overall result indicated a linear increase (p