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|Monday, 29 October 2007 10:28|
Since the onset of the modern era of biotechnology in 1973, scientists have made impressive strides in developing new agricultural biotechnologies. Biotechnologies that enhance productivity and productive efficiency (feed consumed per unit of output) have been developed and approved for commercial use. Technologies that improve productive efficiency will benefit both producers and consumers because feed provision constitutes a major component (about 70 percent) of farm expenditures.
Advances in biotechnology research have allowed impressive improvements to be made in diagnostic approaches, increasing microbial safety of food and improving animal health. The application of genomics, or the study of how genes (DNA) are organized and expressed, and bioinformatics in animal agriculture will provide new genetic markers for improved selection of all livestock species.
The advent of techniques to propagate animals by nuclear transfer (cloning) offers many important applications to animal agriculture, including reproducing highly desired elite sires and dams. Animals selected for cloning will be of great value because of their increased genetic merit for increased food production, disease resistance, reproductive efficiency or will be valued because they have been genetically modified to produce organs for transplantation or products with biomedical application.
Biotechnology also offers considerable potential to animal agriculture as a means to reduce nutrients and odors from manure and volume of manure produced. Development and adoption of these biotechnologies will contribute to a more sustainable environment.
To benefit agriculture and society, products of biotechnology must be accepted by consumers. Central to consumer acceptance is the need to provide effective population-based education programs to enhance public understanding of the safety and benefits associated with technological advances enabled by agricultural biotechnology.
Despite some of the most remarkable advances in biological research, a public discussion still continues about the need for, and safety of, agricultural biotechnology that is fueled by misinformation campaigns funded by animal activists and some consumer activist groups. As we progress towards 2050, the scientific and agricultural communities must be more proactive in developing and delivering biotechnology and agriculture education campaigns for public and policy makers that clearly articulate the merits of current production practices used in animal agriculture.
Moreover, the benefits of investing in discovery research that improves animal agriculture must be championed, and the return on this investment clearly communicated. The agricultural community is going to navigate a period over the next few decades during which we will likely witness growing challenges, especially increased regulatory oversight in addition to the misinformation campaigns funded by activist anti-ag biotechnology groups. For the full benefits of agricultural biotechnology to be realized, regulatory policy that evolves must be guided by the scientific evidence base, not vocal anti-ag biotechnology activist groups.
Food production: Uses of biotechnology in animal production feeding livestock
Biotechnology has led to the development of plant varieties with improved qualities, including enhanced tolerance of herbicides, protection against viruses and insect pests and modifications in nutrient profile. These varieties have been adopted rapidly by American farmers, and the United States accounted for approximately 55 percent of the global area of transgenic crops in 2005 (up from 30 percent in 2001). Genetically modified (GM) crops used for livestock feed include corn, soybean, canola and cotton (cottonseed).
Health and safety are priorities in the development of new food and feed products, including those developed through biotechnological means. Evaluation by governmental regulatory agencies is required for each new biotech plant used for feed or food. Scientific studies evaluating feed components derived from GM plants have focused on beef cattle, swine, sheep, fish, lactating dairy cows and broiler and layer chickens, and these studies have included nutrient composition assessments, digestibility determinations and animal performance measurements.
Evaluations have shown uniformly that feed components derived from GM plants commercialized thus far are substantively equivalent in terms of nutrient composition and are similar in terms of nutrient digestibility and feeding value. Overall, feed components of GM plants result in growth rates and milk yields not different from those derived from non-genetically enhanced feed sources. Studies have reported that when corn has been altered genetically for protection against the corn borer, under certain growing conditions GM plants can have lower mycotoxin contamination, resulting in safer feed for livestock. In addition, no residues of recombinant DNA or novel proteins have been found in any tissue or organ samples obtained from animals fed GM plants.
Advances in understanding the regulation of nutrient use in agricultural animals have led to the development of technologies referred to as metabolic modifiers. Metabolic modifiers are a group of compounds that modify animal metabolism in specific and directed ways. Metabolic modifiers have the overall effect of improving production, productive efficiency (weight gain or milk yield per unit of feed consumed), improving carcass composition (lean-to-fat ratio) in growing animals, increasing milk yield in lactating animals and decreasing animal waste per production unit.
Two classes of compounds have received major focus. The most commonly discussed is bovine somatotropin (bST), which has been commercially used since 1994 for administration to dairy cows to achieve increased milk yield, improve milk/feed and decrease animal waste.
Cloning, a term originally used primarily in horticulture to describe asexually produced progeny, means to make a copy of an individual or, in cellular and molecular biology, groups of identical cells and replicas of DNA and other molecules. For example, monozygotic twins are clones. Animal cloning in the late 1980s resulted from the transfer of nuclei from blastomeres of early cleavage-stage embryos into enucleated oocytes, while cloning of livestock and laboratory animals has resulted from transferring a nucleus from a somatic cell into an oocyte from which the nucleus has been removed.
Somatic cell nuclear transfer also can be used to produce embryonic stem cells, which are undifferentiated, and matched to the recipient for research and therapy that is independent of reproductive cloning of animals. The progeny from cloning using nuclei from either blastomeres or somatic cells are not exact replicas of an individual animal due to cytoplasmic inheritance of mitochondrial DNA from the donor egg, other cytoplasmic factors which may influence “reprogramming” of the genome of the transferred nucleus, and subsequent development of the cloned organism.
Cloning by nuclear transfer from embryonic blastomeres or from a differentiated cell of an adult requires that the introduced nucleus be reprogrammed by the cytoplasm of the egg and direct development of a new embryo, which is then transferred to a recipient mother for development to term. The offspring will be identical to their siblings and to the original donor animal in terms of their nuclear DNA, but will differ in their mitochondrial genes; variances in the manner nuclear genes are expressed are also possible. Although clone is descriptive of multiple approaches for cloning animals, in this article clone is used as a descriptor for somatic cell nuclear transfer.
On December 28, 2006, the Food and Drug Administration (FDA) released a draft risk assessment (RA) on whether cloning affects food safety or animal health, and whether food products from livestock should be sold for human consumption. The draft concludes that “….the available data has not identified any food consumption risks or subtle hazards in healthy clones of cattle, swine, or goats. Thus, edible products from healthy clones that meet existing requirements for meat and milk in commerce pose no increased food consumption risk(s) relative to comparable products from sexually-derived animals.” Publication of the FDA Risk Assessment is an important next step in the process leading to the release of the final regulatory guidelines that will allow food from cloned animals to enter the food system.
Conservation of the environment
Meeting environmental challenges is one of the major issues facing animal agriculture. Animal manure is high in nitrogen (N) and phosphorus (P), both of which can contribute to surface and groundwater pollution. In addition, ammonia and other nitrogenous and sulfurous gasses contribute to poor air quality and offensive odors. Several GM crops have been developed or are being developed to address the environmental issues related to N, P and total manure excretion and odors.
It is exciting that opportunities are now available to decrease P content of manure. These new strategies are based on a more accurate interpretation of P requirements (to not over-feed P) and more precise diet formulation. Collectively, these strategies can lower P content of manure by 25 to 40 percent in ruminants.
A look to the future
The impressive growth in the science of biotechnology and the many resulting products that have been developed for society is one of the most impressive achievements in the history of science. Predicting what scientific discoveries will occur between the present and 2050 will, as always, be more than a bit challenging.
Scientific advances will give us a better understanding of how genes work, and how they can be manipulated to achieve an optimal production outcome that benefits both the producer and consumer. Valuable animals that arise from conventional breeding or genetic manipulation can be propagated forever by cloning. I anticipate that we will be able to do large-scale modification of a large number of genes that will further enhance a variety of target production traits, production efficiency and profitability. The extent to which we can enhance these outcomes will be beyond current predictions.
Before we in the agricultural community get carried away anticipating scientific advances in biotechnology over the next 40 years, there are several key points that must be considered and addressed. First, funding for discovery and applied research in agriculture must be increased.
Second, the discoveries made require a viable private sector to commercialize new products of biotechnology. This is becoming more challenging for a variety of reasons. The process of moving a product through the regulatory approval process is becoming more complex, costly and lengthy. This growing burden makes it challenging for private sector to recover their investment costs from product sales. This is particularly important for agricultural biotechnologies where the margins on products are much lower than biomedical biotechnology products (using similar scientific methods). Over the past 20 years, a number of companies have withdrawn from developing animal health products. What has not been widely addressed is the cost to society if biotechnological innovation in agriculture is hindered or even stopped.
The last point pertains to the activist groups that are actively advocating that the use of biotechnology-derived products be halted. This is an ever-present reality. Many of these groups are well funded and attack animal agriculture on many fronts that range from animal welfare to biotechnology to environmental issues. It is simple to scare the public in 30 seconds; however, we cannot educate them about science, agriculture and biotechnology in 30 seconds.
My encouragement to animal agriculture is to passionately engage in developing and implementing consumer education programs that effectively frame the importance of animal agriculture and promote the need for and benefits of biotechnology in the barnyard. PD
—Excerpts from 5th Mid-Atlantic Nutrition Conference Proceedings
Terry D. Etherton
Department Head of Animal Nutrition at Penn State University