Bruce R. Thomas, Kent J. Bradford                             25 April 2001
Seed Biotechnology Center, Univ. California, Davis
(http://sbc.ucdavis.edu) (email: sbc@ucdavis.edu) (Tel: 530-754-7333)

Via internet at http://sbc.ucdavis.edu/outreach/lecture/livestock_feeds.htm

Feeding trials.  Feeding trials with poultry, swine, fish, cattle and sheep have demonstrated that feeds derived from biotech crop plants are as safe and as nutritious as nonbiotech crops (14).  Bt and nonBt corn hybrids had similar feeding value in beef steers, chickens and swine. Herbicide tolerant and conventional soybeans had equal feeding value in chickens, catfish and cattle.  Biotech feeds are digested normally, so there is no effect on safety of meat, milk or eggs produced by the livestock, according to the Federation of Animal Science Societies (4).

 Future Biotech Feed Crops.  New biotechnology crop traits under development (5) will provide additional benefits to livestock producers in the future.  Potential future traits in biotech crops include more "output traits" that will enhance food and feed qualities.  Biotech crop traits that may reach the marketplace within the next 5 years include corn with improved oil quality and improved protein quality.  Alfalfa crop traits under development include enhanced protein quality and altered lignin for improved digestibility.  Many of our traditional foods and feeds contain toxins and antinutrients such as cyanogenic glycosides, allergenic proteins, glucosinolates, phytate, glykoalkaloids, phenols, protease inhibitors and tannins.  Biotechnology may help to reduce or eliminate these to produce more wholesome feeds.  For example, biotechnology and plant breeding are being used to reduce phytate contents in corn and soybean seeds resulting in improved phosphorus uptake and utilization by livestock.  Biotechnology could also be used to provide phytate digestive enzymes that might be added to the feeds to further reduce the phytate content and increase the feed value.  The strategy of using digestive enzymes as feed additives has already been used successfully to solve a different feed problem in barley.  The high content of glucan polysaccharides in barley and the inability of chickens to digest these glucans makes barley unsuitable as a feed for chickens.  Biotech barley enhanced with a glucan digestive enzyme was fed to chickens and provided feed value equivalent to that of a corn diet.  Vaccines delivered via biotech feeds may help to protect livestock against viral and bacterial diseases.  This could reduce the need for antibiotics in feeds and for vaccine injections to protect the health of livestock.  Biotech crops containing antifungal peptides may reduce fungal contamination in feeds.  Together with the Bt gene strategy for protection against fungi discussed above, this will provide even better protection against mycotoxin contamination of livestock feeds. (14)

Crop Production - Pollen Drift.   Pollen drift from biotech corn crops has been in the news recently, with concern about effects on monarch butterflies. Pollen from corn enhanced for insect protection has little or no effect on the monarch butterflies. Preliminary laboratory studies suggested that Bt genes and Cry protein expression in corn pollen might harm monarch butterflies. Recently more thorough field studies have demonstrated that biotech corn causes little or no harm to monarchs, especially compared to the insecticide spray treatment alternatives. One corn variety with high expression of Cry protein in pollen has been withdrawn from production. Corn varieties currently being grown have only minimal expression of Cry protein in their pollen. Monarch populations have not declined in areas where biotech corn is being grown. The greatest risk to monarchs may be habitat loss, particularly in their overwintering sites (7).

          StarLink Corn. StarLink corn contained a Cry9 protein (Bt gene) that was somewhat resistant to digestion in monogastric animals and therefore might act as an allergen in some people. StarLink corn is approved for animal feed and industrial applications.  During planting and harvesting in 1999 and 2000 StarLink was not kept separate as intended, with some pollen drift into neighboring fields and some postharvest mixing in storage and transport. Thus, StarLink corn became mixed with corn intended for human food.  Some reports of people with possible allergic reactions to StarLink are currently under investigation, but have not been confirmed.  Registration for planting of StarLink has been withdrawn and planting seed for the 2001 corn crop is being carefully tested to ensure that no more StarLink is planted (11).

 International Government Regulation of Biotech Crops.  Export markets for biotech crops are complicated by wide variability in international government regulations and consumer reactions to biotechnology. Many governments are still establishing mechanisms to regulate biotech crops and food products.  The European Union Parliament recently repealed their moratorium on approval of new biotech crops (12), but governments in individual countries also need to act before these markets will open up to new biotech crops.

 Public Debate about Biotech Foods.  There is now a worldwide debate about the use of biotech crops and livestock.  Opponents of agricultural biotechnology raise issues such as: food safety, food labeling, environmental contamination, reduction in biodiversity and concern about possible unknown consequences.  Some of the protest against biotechnology is motivated by broader issues in society such as concerns about corporate monopolization of food, globalization of the economy and reduction of imports to protect local farm economies.   New government regulations have enabled alternative choices for consumers who wish to avoid food products produced from transgenic crop plants.  USDA regulations for organic agriculture certification exclude the use of biotech crop plants or their feeding to organic livestock. An additional consumer choice is provided by recent FDA regulations for voluntary labeling of foods produced without biotech ingredients. Scientific, social, economic and ethical issues are all involved in determining consumer acceptance of agricultural biotechnology.

Consumer surveys.  Two recent public surveys in the US demonstrated that a majority support continued research and expect biotechnology to provide benefits (13).  When asked about food safety issues, very few people indicated any concerns about biotechnology in foods.  Many people are uninformed about how biotechnology contributes to food production, so there is a challenge to provide information about this to the public.  In the US consumers are generally optimistic about biotechnology and believe that government regulations are working to protect public safety.  Careful stewardship of the technology at all steps in the production and marketing chain is critical in order to retain the trust of the public.

Dr. Kent J. Bradford Director	Dr. Bruce R. Thomas Technical Director	Susan Webster Program Representative