Optimisation of dietary energy utilisation for poultry – a literature review

SUMMARY

Feed energy is an important production factor in poultry, representing 75% of the total cost of feed. Therefore, maximising energy digestion and utilisation is essential for cost-effectiveness and sustainability in poultry production. Consequently, accurate energy evaluation of raw material and animal requirements for energy is valuable for precision feeding and optimised benefits in growing chickens. Two key strategies to enhance the utilisation of energy from feed ingredients are the use of exogenous enzymes, such as carbohydrases, and accurate energy requirement prediction. Exogenous carbohydrases can enhance nutrient digestion and absorption, especially in diets with viscous ingredients, in which carbohydrases can enhance the digestibility of saturated fat and protein, by 33% and 3%, respectively, and about 4% energy utilisation. This can improve not only energy utilisation, but also gut health by reducing nutrient flow into the hindgut, as the presence of undigested nutrients fuels pathogenic bacteria proliferation. Moreover, accurate energy bioassays are required to provide values of dietary energy and true availability of energy to the birds. Currently, metabolisable energy (ME) systems are commonly used to evaluate poultry energetics. However, ME does not represent the total energy available to the birds, as it cannot measure the proportion of dietary energy that is lost as heat during feed ingestion, absorption and metabolism. In fact, the ME system can underestimate energy provided by fat by 13% and overestimate energy from proteins by 20% in chicken feeds. As net energy (NE)/ME ratio can vary from 59% to 77% depending on dietary composition, the NE systems are suggested as alternative, more accurate energy measurement methods, as they provide energy values corrected for heat increment. This paper reviews energy sources for poultry and addresses the potential to use NE measurements as a tool to evaluate the ability of feeds and feed additives to improve the exploitation of energy utilisation.

KEYWORDS:

• Net energy
• metabolisable energy
• metabolisable energy efficiency for net energy
• carbohydrases
• indirect calorimetry system
• heat production

Disclosure statement

The authors declare the absence of conflict of interest.

Additional information

Notes on contributors

Sosthene Musigwa

Sosthene Musigwa has just completed his PhD studies in poultry science at the University of New England in 2021 and where he is currently working as a post-doc in poultry nutrition. His research interest are poultry energetics. He has completed a Batchelor of Veterinary Medicine at the University of Rwanda, a Master of Science in International Animal Health from the University of Edinburgh, UK, and a Master of Science in Agriculture at the University of New England, Australia.

Natalie Morgan

Natalie Morgan is currently a Research Fellow in Poultry Nutrition and Lecturer in Animal Nutrition at University of New England. She has over 10 years of experience in poultry nutrition research. She completed her PhD in Poultry Nutrition (2010-2014) and a one year Post-Doc (2014-2015) at Nottingham Trent University, UK, and has been conducting research in non-starch polysaccharides and xylo-oligosaccharides at UNE for the past five years. This has resulted in a number of publications and conference presentations in this field, including international invited speaker invitations.

Robert Swick

Robert Swick currently holds the position of Poultry Research Coordinator at Poultry Hub Australia in Armidale, Australia. Bob has held various positions in industry and academia including Monsanto Company, Novus International, American Soybean Association and University of New England in Australia. Bob has published over 300 technical papers, bulletins, reports and journal articles and holds a patent on a novel grain preservation system. His current interests are animal energetics, protein and amino acid nutrition, gut health and sustainable poultry production.

Pierre Cozannet

Pierre Cozannet joined Adisseo in 2010 as Animal Scientist in pig nutrition. His role aims to conduct R&D programs in order to improve knowledge on enzyme mode of action and practical application, and also to develop new products. He gained a Master’s degree in zootechnical science from the Agrocampus Ouest of Rennes (France). He finalized a PhD at INRA looking wheat distiller grain with soluble nutritional values. His research interests include nitrogen and energy metabolism in non-ruminants, competition among great physiological functions (i.e. nutrition, growth, immunity and reproduction) and global breeding system approach.

Shu-Biao Wu

Shu-Biao Wu has worked in poultry nutrition and health for 12 years. His interests in poultry focus on net energy, necrotic enteritis, nutrigenomics and gut health. A/Prof Wu has interdisciplinary expertise in both animal and plant fields. He received his PhD at The University of Adelaide in 2002. A/Prof Wu has published more than 110 refereed journal papers, supervised 40 PhD and master students, and is the Associate Editor of Animal Nutrition and the Academic Editor of PLOS ONE.