Long-chain omega-3 polyunsaturated fatty acids in ruminant nutrition

Monograph No. 4

Clayton EH (2014)

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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.