Graham Centre Monograph No. 4
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Long-chain omega-3 polyunsaturated fatty acids in ruminant nutrition: benefits to animals and humans Edward H. Clayton Livestock Research Officer – Ruminant Nutrition NSW Department of Primary Industries, Wagga Wagga Agricultural Institute Pine Gully Rd, Wagga Wagga NSW 2650 Graham Centre Monograph No. 4 Edited by: Toni Nugent and Catriona Nicholls August 2014 © State of New South Wales through Department of Trade and Investment, Regional Infrastructure and Services 2014 This publication is copyright. You may download, display, print and reproduce this material in an unaltered form only (retaining this notice) for your personal use or for non-commercial use within your organisation. To copy, adapt, publish, distribute or commercialise any of this publication you will need to seek permission from the NSW Department of Primary Industries. Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (August 2014). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of the NSW Department of Primary Industries or the user’s independent advisor. All sources of information in the current publication are acknowledged in the text. No further reproduction should be made without first obtaining prior written approval of the copyright owner. For updates to this publication, check www.grahamcentre.net/ Published by the NSW Department of Primary Industries. First published August 2014 ISBN 978 1 74256 678 8 Cover design by: Sharon Kiss Cover photo by: Toni Nugent, Graham Centre for Agricultural Innovation Author’s Contact: Dr Edward Clayton, Livestock Research Officer, NSW Department of Primary Industries, Wagga Wagga Agricultural Institute, Pine Gully Rd, Wagga Wagga NSW 2650 Email: [email protected] Citation: Clayton EH (2014). Graham Centre Monograph No. 4: Long-chain omega-3 polyunsaturated fatty acids in ruminant nutrition: benefits to animals and humans. Eds. T Nugent and C Nicholls, NSW Department of Primary Industries, Wagga Wagga, NSW. Available at: www.grahamcentre.net/ Acknowledgements: The cost of printing this Monograph was funded by the Graham Centre. 2 Omega-3 in ruminant nutrition - EH Clayton Graham Centre Monograph No. 4 FOREWORD The Graham Centre Monograph series provides an in depth analysis of issues of importance to mixed farming systems. The aim is to make the information readily accessible to a broad audience including producers, students, researchers and funding organisations. As the consumption of animal products increases globally, the demand for red meat will continue to grow. Along with this increased demand, the quality and health benefits of meat, for example, the possible role of omega-3 fatty acids in disease prevention, will be of greater importance to consumers. This latest Monograph outlines the possible benefits of omega-3 fatty acids from beef and lamb, and the ability to maximise these levels by feeding forage diets. In particular, the role of forage conservation and the inclusion of conserved forage in production feeding rations to achieve this goal is examined. This is the first Monograph focusing on animal nutrition and production. It provides an up-to- date summary of current research, and identifies gaps for future regional, national and international research opportunities. Professor Deirdre Lemerle Toni Nugent and Catriona Nicholls Director, Graham Centre for Editors Agricultural Innovation Omega-3 in ruminant nutrition - EH Clayton Graham Centre Monograph No. 4 3 ACKNOWLEDGEMENTS I would sincerely like to thank Bill McKiernan (former manager, Livestock Production, NSW DPI) for his encouragement to pursue research into the effects of omega-3 fatty acids and the ability to manipulate the omega-3 content of meat. Much of the current review was conceived in the early days of our current research program. I would also like to thank the many researchers at the Wagga Wagga Agricultural Institute that have been involved with various aspects of our research, especially fatty acid analysis, including Richard Meyer, Jamie Ayton and Peter Hawkins. I would like to thank the Graham Centre for Agricultural Innovation and Deirdre Lemerle for supporting our omega-3 research program and for providing preliminary funding for early research examining the effect of omega-3 on animal health and reproduction. I also thank Catherine Gulliver for her help initiating the research program examining the impact of omega-3 on reproduction in sheep. Catherine’s input, hard work and dedication made much of our current research possible. Thank you to the many people who have assisted with the collection of some of the data presented in the current Monograph, including Craig Lihou, Patricia O’Keeffe, the farm staff of the WWAI and a number of students from Charles Sturt University and Sydney University. I would also like to thank John Wilkins and John Piltz for many extremely helpful discussions about the effects of omega-3 fatty acids in sheep and cattle. I am particularly grateful to Robert Taylor and Robert Blake for teaching me a substantial amount about fatty acids and, in particular, fatty acid analysis. Their insights into all things to do with lipid and fatty acid extraction and analysis has helped me to form a solid base from which to start much of our current research. 4 Omega-3 in ruminant nutrition - EH Clayton Graham Centre Monograph No. 4 EXECUTIVE SUMMARY There is continued interest from researchers, health professionals and the general public in the potential health benefits of omega-3 fatty acids. Several theories link the consumption of long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) to reducing the incidence of disease conditions including cardiovascular disease, inflammatory diseases, such as arthritis, and mental health disorders. Research efforts have focussed on the impact of two LCn- 3PUFA found in oily fish: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). While EPA and DHA are only found in relatively low concentrations in red meat (including beef and lamb) compared with oily fish, the total LCn-3PUFA concentration in meat including docosapentaenoic acid (DPAn-3) is significant. The impact of different production systems on the LCn-3PUFA content of meat has gained significant attention during the past 10–15 years. The current review summarises several possible health benefits of LCn-3PUFA in ruminants and humans and outlines the effects of different production systems on the content of beneficial fatty acids in meat. The LCn-3PUFA status of meat is significantly improved by incorporating fresh or conserved forage, compared with grain and concentrates, into the diet of ruminants. The ability of forages to maximise the amount of LCn-3PUFA in meat is dependent on the nature of forage, including the amount and type of lipid present and, is greater when animals consume fresh forage compared with hay or silage. Several research programs have examined the manipulation of lipid and fatty acid content of forages in order to maximise the amount of omega-3 available. There is scope to increase the amount of omega-3 available in silage by ensuring that it is produced under optimal conditions, including limiting wilting where possible and maximising the efficiency of fermentation. The current Monograph also reviews the observed and recommended intakes of LCn-3PUFA in the Australian population and the contribution of red meat intake (beef and lamb) to this intake. Red meat contributes approximately 40% of the average daily intake of LCn-3PUFA for adult men and women in Australia and there is the potential to significantly increase the consumption of LCn-3PUFA from meat by manipulating the diet of ruminants by incorporating forage or feeding forages with improved omega-3 availability. Several opportunities for future research programs are identified following the review of previous research, including the need for a survey of the amount of omega-3 available in pastures and forages grown in Australia and examination of the impact of ensiling forage on omega-3 concentrations under Australian conditions. There is a great need to determine measureable improvements in the health of those consuming meat enriched with LCn-3PUFA following the incorporation of forage into production diets. If the consumption of meat with enhanced LCn-3PUFA can decrease the incidence of disease, this would provide an incentive for producers to deliver this meat into the market. KEYWORDS Ruminant nutrition, omega-3 polyunsaturated fatty acids, health benefits, animal production. Omega-3 in ruminant nutrition - EH Clayton Graham Centre Monograph No. 4 5 TABLE OF CONTENTS FOREWORD .......................................................................................................................................... 3 ACKNOWLEDGEMENTS .................................................................................................................... 4 EXECUTIVE SUMMARY ..................................................................................................................... 5 TABLE OF CONTENTS ........................................................................................................................ 6 TABLE OF FIGURES ............................................................................................................................ 8 TABLE OF TABLES .............................................................................................................................