Phosphorus bioavailability, amino acid digestibility and metabolizable energy of broiler chick diets supplemented with low-oil distiller’s dried grains with solubles

Abstract

Phosphorus (P) bioavailability, crude protein (CP), amino acid (AA) digestibility, and apparent metabolizable energy (AMEn) were determined in broiler chick diets, supplemented with one of two low-oil distiller´s dried grains with solubles (oil contents 6.54% and 5.35% for DDGS A and B, respectively). Diets were provided ad libitum in a mash form, from days 8 to 21 of age. In Experiment 1, one day old male broiler chicks (n=210) were assigned to one of 7 treatments, with 3 replicates of 10 birds each. Animals in treatment 1 (T1) were fed a basal diet formulated to be deficient in nonphytate P (0.14%). Birds in T2 and T3 received the basal diet supplemented with 0.05% or 0.10% of P from monodicalcium phosphate (MCP), respectively. Phosphorus from DDGS was added to diets in T4 (0.05% from DDGS A), T5 (0.1% from DDGS A), T6 (0.05% from DDGS B) and T7 (0.1% from DDGS B). Percent of inclusion of DDGS was dictated by total P content as determined by chemical analyses. Growth performance and P intake were assessed in all birds. Phosphorus bioavailability was determined using the slope ratio assay, with tibia ash as the response variable. For Experiment 2, one-day-old male broiler chicks (n=200), were assigned to 5 treatments with 4 replicates of 10 birds each. A sorghum-soya control diet was given to animals in T1. Treatments 2 and 3 included this same diet supplemented with either 5% or 10% of DDGS A. Birds in T4 and 5 received the control diet with either- 5% or 10% of DDGS B. Amino acid digestibility was measured from ileal contents in 7 euthanized birds from each group at day 21. Apparent metabolizable energy was determined in oven dried feces from all animals during the last 3 days of the experiment.  Weight gain and feed consumption increased (P <0.001) with larger inclusion of dietary P in birds from experiment 1. Relative P bioavailability for DDGS A and B was 72% and 86% respectively, from a P total content of 0.85% and 0.94%.,. Growth performance was similar for all treatment groups in experiment 2 (P >0.05). The average apparent ileal amino acid digestibility coefficient for DDGS A 76.5% and B was 76.4%. No differences were found for essential AA coefficients between the two DDGS (P >0.05). The AMEn values on a dry matter basis were 2828 and 2854 kcal/kg for DDGS A and B, respectively.