Originally published July 22 2015
Scientists inject nematode genes into cattle DNA to alter beef composition
by David Gutierrez, staff writer
(NaturalNews) Scientists are celebrating the "successful" genetic engineering of cows -- spliced with genes from nematode worms -- that make beef with a higher content of omega-3 fatty acids, in a study conducted by researchers from Northwest A&F University and the National Beef Cattle Improvement Centre (both in Yangling, China), and published in the journal Biotechnology Letters.
There are just two problems. First, nearly all of the genetically engineered cows died as calves.
Second, studies have shown that there's already an easier way to make beef "higher" in omega-3s: Raise the cows on a natural diet of grass, rather than grain- and byproduct-based feed.
Only three cows survived procedure
Omega-3s are essential fatty acids that play a key role in human nutrition, including childhood brain development. A diet high in omega-3s has also been shown to lower the risk of obesity, cardiovascular disease and certain neurodegenerative diseases such as Alzheimer's. Experts say that in recent decades, however, the typical Western diet has become too low in omega-3s, as sources of fat high in omega-3s have been displaced by sources of fat higher in omega-6s (also essential, but now over-consumed compared to omega-3s).
Conventional nutritional wisdom holds that beef contains only negligible levels of omega-3s. So the Chinese researchers sought to boost omega-3 levels in beef by introducing a nematode gene called fat1 into the fetal cells of Luxi Yellow cattle. This gene was intended to convert omega-6s in the cows' bodies into omega-3s, and this did seem to occur: When slaughtered, the cows yielded beef five times higher in omega-3s.
"We have provided the first evidence that it is possible to create a new breed of cattle with higher nutritional value in terms of their fatty acid composition," researcher Linsen Zan said.
Yet by the age of four months, 11 of the 14 genetically modified calves had died from inflammation and an infection known as hemorrhagic septicemia. The researchers believe that the genetic engineering procedure somehow hampered the calves' development, leading to their deaths.
"There is much to learn about the best scientific techniques and the best husbandry required to make beef a rich animal source of omega-3 oils for human nutrition, but we have taken the first step," lead author Gong Cheng said.
Grass-fed beef already has omega-3s
Studies suggest, however, that there is a much less complicated and lethal way to make beef higher in omega-3s: Just feed cows grass, the food they evolved to eat.
In a study published in the Asia Pacific Journal of Clinical Nutrition in 2006, researchers from RMIT University in Melbourne, Australia, fed 54 cows on either a grass diet or on a short-term or long-term grain-based feed diet. The grain diet mimicked the average Australian feedlot ration, containing more than 50 percent grain, with added cottonseeds and protein meal. Short-term feeding lasted for 80 days; long-term feeding lasted for 150-200 days.
The researchers found that beef from the grass-fed cows was significantly higher in both total and long-chain omega-3s than either grain-fed group. It was the only beef that met the threshold
recommended by Australian food standards for a food to be considered a source of omega-3s.
Notably, grain-fed beef was also higher in "naturally occurring" trans fats, with long-term feeding causing the greatest increase.
Another study, published in Nutrition Journal in 2010, reviewed 30 years of research and concluded that grass-fed beef is higher not just in omega-3s, but also in antioxidants (including some with cancer-fighting properties). The saturated fats found in grass-fed beef are also less likely to elevate cholesterol than those found in grain-fed beef.
"However, consumers should be aware that the differences in [fatty acid] content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef," the researchers wrote. "In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A)."
Sources:
http://www.dailymail.co.uk
http://www.nutritionj.com
http://www.ncbi.nlm.nih.gov
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