Critical amino acids to improve gut health of chickens fed reduced protein diets


Maintaining intestinal health and growth remains a concern as demand increases to limit the use of antibiotics in poultry production. There is also an interest to feed meat chickens with lower protein diets using more synthetic amino acids to reduce the environmental impact of poultry production. In that situation, closer attention needs to be given to those amino acids that maintain the intestinal barrier, decrease the variability of nutrient utilization and absorption, and make the birds less vulnerable to an immunological stress while not compromising performance. Threonine, arginine, and glutamine are regarded as the three most critical amino acids involved in metabolism, function, integrity and health of intestinal tract across different species. The optimum nutrition and more importantly nutrient-by-nutrient interactions between these amino acids are not understood in poultry particularly for reduced protein diets. The overall aim of the project is to investigate the optimum nutrition and interrelationships between these three critical amino acids and subsequent intestinal integrity and growth in meat chickens fed reduced protein diets. The three specific objectives of the project are; 1) effect of reduction of protein content and supplemented amino acids on intestinal development, barrier function, gut health biomarkers and growth; 2) role of glutamine, threonine and arginine on growth and intestinal function of birds fed lower protein diets; 3) therapeutic effects of these three amino acids in absence of antibiotics under enteric inflammation. Expected outcomes include reduced risk of intestinal inflammation and a sustainable growth of chickens fed low protein diets.


Chicken Meat

Research Organisation

Minister for Primary Industries and Regional Development acting through the South Australian Research and Development Institute

Objective Summary

This research addresses Objective 1 listed in the Chicken Meat R&D program and specific priorities of nutritional strategies to increase feed efficiency, gut health and reduce environmental impact of poultry production. This project aims to address two key factors of interest concurrently; i) reduction in protein content of diets and ii) intestinal function and health in relation to most influential amino acids involved in the function of intestine. Much research has been done on low-protein amino acid supplemented diets but there is very little scientific evidence on their impact on intestinal health and function, inflammation and immune response. The key question is “When limiting essential amino acids are provided in low protein diets in synthetic form, is the intestinal health affected and if so, can gut health be enhanced by extra amino acids?” Overall objective: investigate the optimum nutrition and interrelationships between critical amino acids and subsequent intestinal health, integrity and growth in meat chickens when fed reduced protein diets The specific objectives are: 1. To investigate the optimum nutrition of threonine, arginine and glutamine in relation to their specific effect on intestinal function 2. To evaluate interrelationships between these three critical amino acids for intestinal permeability 3. To evaluate the impact of experimental treatment on gut health by looking at selected biomarkers related to epithelial barrier function

Project Code


Project Stage


Project Start Date

Saturday, July 30, 2016

Project Completion Date

Thursday, May 30, 2019

National Priority

An environmentally sustainable Australia

National Priority

CME-Improve chicken meat production through the whole supply chain