Swine: Health Facts About Flax
Flax is a blue-flowering crop grown in abundance in Canada's Prairie Provinces (see Figure 1). Flax seed is flat, oval and pointed at one end and can range in colour from golden yellow to dark reddish brown. Over 40% of the world's flax is produced in Canada. In 2001, just over 700 thousand tonnes of flax were produced in Canada, with the majority (70%) grown in Saskatchewan.
According to the Canadian Grain Commission, the 2001 crop tested at 24% protein, 44% polyunsaturated oil, with 56% omega-3 alpha linolenic acid and 15% omega-6 linoleic acid in the oil (see Table 1). As with many crops, the nutrient composition of flax can vary considerably with genetics, growing conditions, seed processing and analytical methods.
1 Dry matter basis, 2 N x 6.25; Dry matter basis
Flax's claim to fame is that it is nature's richest source of omega-3 fatty acids. Flax is also one of the richest sources of lignans, providing 75-800 times more plant lignans than most other plant sources. Studies in humans have suggested that, as a result of these unique properties, flax can have a positive effect on cholesterol levels, the autoimmune system and heart disease, and may also play a role in preventing cancer. Other oil-bearing seeds like corn, sunflower and peanuts contain omega-6 fatty acids, but flax is specifically known for its high levels of omega-3 fatty acids.
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. Flax has been successfully incorporated into the rations of laying hens, resulting in the production of omega-3 enriched eggs. The Flax Council of Canada reports that these nutritionally-enhanced eggs now supply 4% of the Canadian egg market. Researchers have also included flax in dairy cattle rations in an attempt to influence milk-fat composition. Research is ongoing to make omega-3 milk a commercial reality. Flax is also attracting attention in the pet food industry as researchers suggest that feeding flax may improve pet health in a manner similar to their human companions.
Twelve years ago, 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.
Research conducted at the University of Manitoba added 5% flax to gestation and lactation diets, replacing some of the soybean meal and tallow in the rations. Sows that ate flax had higher progesterone levels, therefore improving survival of embryos in the uterus. On a commercial farm, sows that were fed the 5% flax ration delivered one more piglet per litter compared to the control group (11.5 vs. 10.4) and produced heavier piglets at birth (I.27 vs. 1.18 kg). The milk from the sows fed flax had a higher level of unsaturated fatty acids, resulting in heavier weaning weights (4.6 kg vs. 4.3 kg). In addition, sows fed flax lost less weight and maintained more backfat during lactation than sows fed standard rations. As a result, weaning-to-breeding interval decreased by 3 days for sows fed flax compared to the control group (4.8 vs. 7.5-8 days).
Good news stories like this have prompted international feed manufacturer, Ridley Inc., to test flax in their U.S. hog production facility. The Flax Council of Canada is working cooperatively with Ridley Inc. to conduct feeding trials using 5% flax in corn-soybean meal rations. The trials, which began in December 2001, are testing whether sows fed rations containing flax can match the barley-based Manitoba results and increase the U.S. industry average number of piglets per litter. Historically, the U.S. has been one of Canada's biggest export markets for flax, but shipments of flax have declined over the past five years as U.S. domestic production of the crop has grown. The Flax Council of Canada sees this as a tremendous opportunity. With US marketings at 100 million pigs per year, using even small amounts of flax in US pig feed could significantly increase demand for Canadian flax.
Visit the Flax Council of Canada's web site.
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