Over the past few years there has been a growing awareness between dietary fat and life style diseases. Here, Eric Russell looks at latest research which suggests that saturated fatty acid content of meat can be reduced using different feeding regimes.
After years of fat being regarded as a four-letter word, research is showing that n-3 polyunsaturated fatty acids (PUFA) offer significant health benefits to consumers.
Now, researchers at the University of Bristol in the UK are investigating the start of the fat production chain to see if an increase in n-3 can PUFAbe made while meat is still on the hoof.
The Division of Farm Animal Science (DFAS) in the university's Veterinary School, is now running a research programme that aims to understand the factors of animal production and processing that can affect meat composition, colour and eating quality. It covers pigs, sheep and cattle.
The results show how the saturated fatty acid content of meat can be reduced using different feeding regimes, and how the polyunsaturated fatty acid content can also be increased.
Consumer awareness
Dr Mike Enser, a member of the division, says that consumers are becoming more aware of the relationship between dietary fat and the incidence of life style diseases such as coronary heart disease.
So meats that offer higher levels of n-3 will become more attractive and could command a price premium.
Doubling intake
A few years ago, one UK government recommendation was for people to double the intake of n-3 PUFA from the current population average of 100mg per day.
Cattle and sheep meat are potentially good sources of the n-3 PUFA µ-linoleic acid, which clinicians suggest is at too low a level in our diet at the moment.
Traditionally, the generally saturated nature of fatty acids in ruminant meats has caused negative effects on human health. This occurs because dietary unsaturated fatty acids are biohydrogenated by rumen micro-organisms.
A solution is to feed animals with fatty acids that are not significantly hydrogenated by ruminal micro-organisms.
Results show this can be achieved by including whole seed linseed or fish oil in the diet of cattle and sheep, when greatly increased n-3 content is observed. But appropriate pre-treatment of these additives has a significant effect on the end result.
By comparison, the fatty acid content of meat in pigs can be quite easily changed because feed fatty acids are absorbed unchanged from the intestine into muscle and fat tissue.
Sensor aspects
The research at Bristol also involves the Institute of Grassland and Environmental Research and other universities and organisations. Cattle are fed diets containing n-3 PUFA and the meat is measured for shelf life and sensory aspects using a 10-member trained taste panel.
It is also measured for fatty acid content and composition of muscle and fat tissues including trans fatty acids, muscle phospholipid types, C20-22 PUFA and conjugated linoleic acid.
The overall aim is to determine how fatty acids affect the nutritional value and flavour of beef.
Sensory assessment suite
Professor Jeff Wood, head of the Division of Farm Animal Science in Bristol's Veterinary School, says that the division comprises some 35 academic and support staff. Its facilities include the only fully licensed abattoir in the UK higher education sector, meat processing plant and a computerised sensory assessment suite.
The division is also researching the effect of different grass types on fat content and fatty acid composition on beef in order to provide objective information.
Professor Wood says that there is plenty of anecdotal evidence but adds that there is little convincing scientific proof to show that animals grazing certain types of grasses, herbs and shrubs produce distinctive flavours in the meat.
A new project funded by government and commercial companies will further develop the research on beef flavour and the associations with muscle fatty acids. Angus and Friesian-Holstein cross cattle will be reared to between six and 18 months of age on grass or cereal-based diets and the effects on muscle components and beef flavour studied.
A European project is studying muscle fatty acid composition and sensory characteristics in sheep that are typically found in seven EU countries. Dietary modification is also being used to determine whether genetics or nutrition have the greater effect on these characteristics.
Feeding regimes
The results of the Bristol University research should stimulate fresh consumer interest in beef once changes to animal feeding regimes are widely adopted.
But this effect could be significantly enhanced by a strong marketing campaign, which will require the efforts of the whole industry.
This two-fold approach is just what is needed by the UK farming industry just now.
