The Energy Value for Broiler Chickens of Heat-Treated and Untreated Amaranth Grain, with and without Enzyme Addition

Abstract

Amaranth is a pseudocereal which can thrive in conditions of drought and limited inputs. Samples of amaranth grain were subjected to proximate analysis with standard laboratory methods. We conducted two experiments to determine apparent (corrected to zero nitrogen balance) metabolisable energy (AMEn) content of untreated (UAG) and heat-treated (HTAG) amaranth grain for Ross-308 male broiler chicks (35–42 d and BW 2141 ± 10.41 g). In each experiment, 10 assay diets (ADs) were fed to 400 birds in individual metabolism cages in a 2 × 5 factorial design. ADs were obtained by substituting amaranth for the main ingredients in the reference diet (RD). Two levels of enzyme addition (0 and 0.55 g/kg) and five amaranth replacement rates (0, 150, 300, 450 and 600 g/kg) were used, and metabolism trials were conducted using the total excreta collection method. Two regression equations were estimated for UAG, with and without enzyme addition, that determined the AMEn content of UAG as 3264 and 3255 kcal/kg, respectively. For HTAG, the AMEn contents with and without enzyme addition were 3973 and 3828 kcal/kg, respectively. Thus, enzyme addition improved the energy value of UAG and HTAG by 0.28 and 3.8%, respectively. The AMEn value of HTAG was 708 and 573 kcal/kg higher than UAG in diets with and without enzyme addition, respectively. Thus, we conclude that there was more benefit from heat treatment than enzyme addition, but there was a synergistic effect of heat treatment and enzyme inclusion on the metabolisable energy concentration of amaranth in the diets of broilers.

Keywords

• amaranth grain
• climate change
• drought
• metabolisable energy
• enzyme supplements