By: Emmy Koeleman
The addition of flax to livestock rations has focused on two main objectives – the production of nutritionally enhanced human food products and enhanced health, productivity and performance of the animals. Linseed meal is a by-product of flax.
Oil is extracted from the seed by either the mechanical process or the solvent process. Linseed meal is the finely ground residue (known as cake, chips, or flakes) remaining after the oil extraction.
Linseed is favoured in rations for ruminants, horses, and sometimes, for sow diets, but is rarely used for poultry because of its poor amino acid profile, its high fibre, and its laxative nature. Poultry, beef, pork, milk and eggs can be modified by the dietary lipid profile fed to the animal, allowing the producer to produce high quality food products with added omega-3 fatty acids for the discerning consumer. Since flax is grown in fields with higher levels of selenium, linseed meal contains a higher selenium content than other feeds.
Feeding linseed can be very beneficial for horses. A horse cannot produce essential fatty acids (omega-3 and omega-6 are in their body), thus they are an essential part of his diet. Characteristics of a lack of essential fatty acids may include a dull coat with dry itchy skin and cracking hooves. Flax also is a rich source of fibre, especially soluble fibre which gels when exposed to water (similar to psyllium). It is helpful in preventing impaction and sand colic as the fibre swells and the gel-like consistency traps and suspends sand, bringing it out of the system. The fibre is rich in lignans, substances believed to be linked to the cancer fighting effects of a high fibre diet. It also has anti-viral, anti-fungal and anti-bacterial properties. Supplementing horses with linseed can therefore help with many conditions including clearing up skin conditions, relieving arthritic and inflammatory pain, increasing bone strength and improving skin and coat.
Benefits for pregnant sows
Linseed flakes can be used at a 4-5% inclusion rate. Research in young growing pigs showed that feeding 5% flax was a means of increasing omega-3 fatty acids in pork. In 1995, researchers at South Dakota State University tested 5%, 10% and 15% flax in a corn-soybean meal ration during the final 25 days of finishing. Results showed that the level of omega-3 fatty acids increased in the final product.
A consumer taste panel did not notice any difference in the loin meat or pastry made from the lard, however differences in the bacon were detected when the rations contained more than 5% flax. Linseed can also have benefits for pregnant sows. By feeding the linseed before partus, less manure is present in the colon which means that the partus goes smoother and quicker (which in turn increases the survival rate of the piglets).
Not for poultry
Linseed oil is a rich source of linolenic acid which can be incorporated into the meat and eggs of birds to which it is fed. The total omega-3 fatty acids are increased in these poultry products; however, there is some evidence that a fish flavour may result.
However, linseed meal has not been a suitable feedstuff for poultry. It could satisfactorily replace the protein equivalent of soybean meal up to 2 or 3% of the diet, but higher levels caused noticeable reduction in gain and feed efficiency in broilers and poults. The adverse effect of feeding linseed meal was greater than one would predict from the nutritional contribution to the diet and there was concern that it contained a toxic factor. At one time, it was speculated that cyanide from its cyanogenetic glucoside might be responsible for the adverse feeding value. Because of these anti nutritional factors it is not recommended to use linseed in poultry diets.
Producing healthy beef
Ruminants are more suited to dealing with the anti nutritional factors that are present in linseed. Its use in beef and dairy cattle is therefore much higher than in monogastrics. It is often added to calf and beef diets because it increases coat health.
The animals therefore look better which is beneficial for selling them on the market. A study done in 2007 showed that cows fed a diet rich in omega-3 produce enriched meat.
The study – done by Kansas State University – suggests that raising cattle on flaxseed diet (10%), rich in alpha-linolenic acid, leads to increases in the omega-3 content of the meat, which could then be passed on to the consumer. The researchers compared flaxseed-fed cattle and corn-fed cattle and found omega-3 fatty acids levels in the cooked beef was double in the flaxseed-fed animals than that found in their corn-fed counterparts (83 versus 44 milligrams per 100 grams).
The study showed that improving the nutritional quality of beef, in this case omega-3 fatty acids, by simply changing a part of the cattle’s diet is possible.
Source: Feed Mix magazine – Volume 17 No. 2 (2009)