Dr. Jacquie Jacob Ph.D., University of Kentucky
NOTE: Before using any feed ingredient make sure that the ingredient is organic, listed in your Organic System Plan, and approved by your certifier.
Flax was first brought to North America for its stem fiber, which was used in the making of linen and paper. Today, flax seed is grown in the United States and Canada as a commercial oil crop. Linseed oil is pressed from flax seed, which is further extracted with a petroleum solvent. Industrial linseed is not suitable for food or feed. The remaining flax seed meal, however, has been used for animal feeds.
Flax seed is unique among oilseeds because it is high in alpha-linolenic acid (Bhatty, 1995). Flax is one of the most concentrated sources of unsaturated fatty acids available in animal feedstuffs for poultry. Flax seed contains 35-45% oil, of which 45-52% is alpha-linolenic acid (Caston and Leeson, 1990).
Nutrient content of flax seed (Batal and Dale, 2010)
Flax seed is used in the United States and Canada in the production of omega-3 enriched eggs (Hayat et al., 2009). The increase in polyunsaturated fatty acids is accompanied by a decrease in saturated fatty acid, resulting in a healthier fat profile. Feeding flax seed to laying hens results in a six- to eight-fold increase in the omega-3 fatty acid content of eggs. Such eggs are equivalent to 113 g (4 oz) of cold water fish as a source of omega-3 fatty acids (Berglund, 2002). Najib and Al-Yousef (2010), however, reported that while feeding 15% flax seed increases the omega-3 fatty acid level of eggs at dietary levels higher than 10%, there is a significant drop in egg production. The ability of flax seed inclusion in the diets of laying hens to increase omega-3 levels in eggs is dependent on the strain of laying hen being used, the diet being fed, and the age of the hens (Scheidler et al., 1998).
While feeding 10% flax results in significantly higher levels of omega-3 fatty acids in both brown and white egg layers, long-term use of flax seed has been shown to increase the incidence of liver hemorrhages in supplemented laying hens (Bean and Leeson, 2003). The cause of the increased liver hemorrhages is unclear. Researchers hypothesized that the livers of flax-fed birds contain more long- chain unsaturated fatty acids, which are more prone to oxidative rancidity, and suggested that vitamin E supplementation may be needed to reduce lipid oxidation products in the liver of flax-fed hens (Cherian and Hayat, 2009). Research has shown that replacing corn in layer diets with pearl millet reduces the amount of flax seed needed to obtain omega-3 enriched eggs (Amini and Ruiz-Feria, 2007).
Inclusion of flax seed in broiler diets has been shown to increase the omega-3 fatty acid levels in the meat (Ajuyah et al., 1991). The effects are different with breast and thigh meat, with thigh meat more likely to have sensory problems. Linolenic acid is preferentially increased in dark meat, while long chain omega-3 fatty acids increase preferentially in white meat (Gonzalez-Esquerra and Leeson, 2000). This may account for the difference in taste tests.
It is not necessary to feed flax throughout the entire grow-out period to produce omega-3 enriched chicken meat. Feeding 10% flax seed for only the 24 days before processing is necessary to achieve optimum omega-3 enrichment of breast meat. Only 5 days are needed for optimal omega-3 levels in thigh meat (Zuidhof et al., 2009). Some researchers, however, have shown that while feeding 15% flax seed increased the omega-3 fatty acid level of dark chicken meat, inclusion levels as low as 5% resulted in reduced body weight gain and feed efficiency (Najib and Al-Yousef, 2011).
Coccidiosis, caused by several species of Eimeria (protozoa), is a problem in many broiler operations. Feeding diets supplemented with omega-3 fatty acids suppresses the development of E. tenella in the ceca of chickens (Allen et al., 1996), but does not reduce E. maxima levels in the middle of the intestines and may actually make lesions worse at high parasite doses (Allen et al., 1997).
Enzyme addition is reported to improve the nutritive value of flax seed for broiler chickens (Jia and Slominski, 2010) and egg laying hens (Jia et al., 2008). Addition of enzymes that break down carbohydrates has been shown to improve the energy utilization from full-fat flax seed, enhancing its feeding value for poultry. Pelleting was also reported to improve nutrient availability from flax seed (Jia and Slominski, 2010).
For more information refer to the Flax Feed Industry Guide
This is an eOrganic article and was reviewed for compliance with National Organic Program regulations by members of the eOrganic community. Always check with your organic certification agency before adopting new practices or using new materials. For more information, refer to eOrganic's articles on organic certification.