Performance, bone characteristics and physiological parameters of broilers fed nutrient-restricted diets supplemented with multicarbohydrase complex associated with high levels of phytase

Summary An experiment was conducted to evaluate high doses of phytase associated with multicarbohydrase complex in diets with a nutritional reduction on feed cost, performance, intestinal morphometry, digesta viscosity, blood and bone parameters, and carcass yield of broilers. For this purpose, 1,540 1-day-old male broiler chicks were distributed in a completely randomized design with 5 treatments, with 14 replicates and 22 birds each. The treatments consisted of the following: positive control (PC), a diet meeting the nutritional requirements without enzymes; negative control (NC), a PC diet with a reduction of 100 kcal/kg AME, 0.15% available P, 0.12% Ca, 4% digestible lysine, and 5% Na; NC diet + multicarbohydrase complex (MCC) + phytase at 3 levels (1,000, 1,500, and 2,000 FTU/kg). The results demonstrated that the use of phytase associated with MCC in nutrient-restricted diets maintained broiler performance in the prestarter phase. From 1 to 42 d, broilers fed enzyme-supplemented diets had a better performance than those receiving nutrient-restricted diets without enzymes. The different levels of phytase associated with MCC affected the serum biochemical parameters of broilers; however, these modifications did not influence bone characteristics. The mode of action of enzymes is substrate-dependent, which may have limited enzyme activity. As a result, no improvements in carcass yield or intestinal and bone parameters were observed. It is concluded that diets with nutritional reduction and addition of 1,000 FTU/kg phytase in association with MCC maintain the performance and is a feasible strategy to reduce feed cost.