Abstract
This experiment evaluated the effects of supplemental protease in maize-based diets formulated with reduced density of digestible amino acids (dAA) on net energy (NE) utilisation and nutrient digestibility in broilers. A total of 312, one-day-old, male broilers (Ross 308) were randomly distributed into 24 floor pens and fed one of three treatments, with eight pen replicates per treatment throughout the starter (1 to 14 d of age) and grower (15 to 28 d of age) phases. Dietary treatments consisted of a positive control (PC) reference diet, a negative control diet (NC; dAA density 60 g/kg less than PC diet), and a NC diet with supplemental protease (200 mg/kg). All diets contained supplemental phytase (200 mg/kg) and xylanase (200 mg/kg). The reduction in dAA density between the PC and NC did not affect (P>0.05) NE, but protease supplementation in the NC diet increased (P<0.05) NE by 0.27 MJ/kg, compared with those receiving the NC diet without protease. The reduction in dAA for broilers fed the NC and PC diets did not (P>0.05) affect nitrogen, starch, or DE in the jejunum or ileum. Likewise, no differences (P>0.05) in jejunal (nitrogen, starch, and DE) and ileal (starch and DE) digestibility values were observed between those offered the NC diets without or with protease, but a small difference (P<0.05) in ileal nitrogen digestibility was observed.
Highlights
Modulating broiler digestive dynamics can affect nutrient utilisation, growth performance and economics of production
These alterations can affect nutrient balance and digestible amino acid (AA), which can affect nutrient utilisation and performance, if not accounted for in the least-cost formulation. The objective of this experiment was to explore the effects of protease supplementation, in combination with phytase and xylanase, in a plant protein, maize-based diet formulated with reduced concentrations of dAA on nutrient digestibility and net energy utilisation in broilers
Dietary treatments consisted of a positive control (PC) reference diet, a negative control diet (NC), and the NC diet with supplemental protease (15,000 U/kg)
Summary
Modulating broiler digestive dynamics can affect nutrient utilisation, growth performance and economics of production. Cowieson et al (2019) demonstrated that protease supplementation, in conjunction with a phytase and xylanase, influenced AA digestibility, apparent metabolisable energy (AME) and net energy (NE) utilisation in broilers.
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