Optimising amino acid profiles and energy in reduced-protein diets


This proposal includes five feeding studies and all the feeding studies will be floor pen studies from 1-42 days post-hatch. Broiler chickens will be raised under conditions that is close to commercial practice. Wheat-based diets with 10% whole grain for grower diets and 15% whole grain for finisher diets, unless otherwise specified. Broiler chickens will be offered starter, grower and finisher diets from 1-14, 15-28 and 29-42 days post-hatch, respectively. The feeding studies will fully comply with specific guidelines approved by Research Integrity, Animal Ethics Committee of The University of Sydney. All the experimental diets will be iso-energetic with similar DEB, fibre content and digestible lysine and amino acid profiles unless it is specified in the design. All feed ingredients will be analysed for gross energy, amino acids, minerals and nitrogen prior to feed formulation and the diets will be steam-pelleted at 80ºC.


Chicken Meat

Research Organisation

The University of Sydney

Objective Summary

Objectives: The aim of this project is to investigate the amino acid requirements and validate ideal protein ratios of modern genotype broiler chickens in the context of reduced-protein broiler diets containing high inclusion levels of crystalline amino acids. It will include five feeding studies including full factorial and response surface designs. The four specific objectives are: AIM 1: To determine the most suitable ideal protein ratio or amino acid profile for optimal growth in conventional and reduced-protein diets based on wheat AIM 2: To determine the fourth limiting amino acids in reduced protein diets with typical feed ingredients used in Australia. AIM 3: To determine accumulated lysine responses in growth performance and carcass yield during different growing phases in broiler chickens offered reduced protein diets AIM 4: To determine how to best adjust metabolisable energy in reduced protein diets for optimal growth performance and minimal abdominal fat.

Project Code


Project Stage


Project Start Date

Thursday, July 11, 2019

Project Completion Date

Thursday, July 21, 2022

Journal Articles From Project

Assessment of limiting dietary amino acids in broiler chickens offered reduced crude protein diets Animal Nutrition (Issue: under review on 30/1/2022), The Impact of Digestive Dynamics on the Bioequivalence of Amino Acids in Broiler Chickens. Frontiers in Bioscience-Landmark (Issue: 27 on 8/4/2022)

National Priority

An environmentally sustainable Australia

National Priority

CME-Improve chicken meat production through the whole supply chain