Advances in Animal Health: Vaccines from Biotechnology
Meeting a Critical Demand
Raising livestock has long been a key element of agriculture around the world. Now, with increasing international demand for protein, it's becoming even more critical to world food production.
However, modern livestock production presents challenges. Protecting animals from disease is a concern. Enhancing livestock productivity must be balanced with care for the animal's welfare. Biotechnology contributes to our ability to keep livestock healthy and productive.
Biotechnology involves the use of the natural processes found in microorganisms, plants and animals. It has unlocked many of the mysteries of the genetic make-up of animals. It has also expanded our understanding of disease, immune responses and other body functions in livestock.
Protecting Animal Health
Biotechnology can enhance or protect animal health in a number of ways. For example:
- Livestock nutrition has been improved through better diet formulations and the addition of feed enzymes to aid digestion.
- Carefully timed feeding of special diets or feed supplements improves disease resistance.
- Improved tests detect a wider range of viruses, bacteria and parasites.
- New drugs provide better disease treatment.
- Genetic selection of hornless cattle could greatly reduce the need for de-horning.
- New vaccines protect animals from a wider range of diseases. They can also reduce the risk of contamination by bacteria, like E. coli, that cause illness in humans. Another group of biotech vaccines can alter animals' body functions to safely and effectively improve productivity.
Of all these biotech developments, new vaccines offer some of the most exciting potential for protecting and improving animal health.
How Do Vaccines Work?
Vaccines stimulate an animal's immune system. They introduce disease-signaling proteins called antigens into the animal, so that its immune system produces antibodies. The antibodies remain in the animal, protecting it from disease.
Traditional vaccines have some drawbacks. They use the entire disease-causing organism, in an altered form that does not transmit the illness. However, these vaccines contain unnecessary proteins which can cause bad reactions or side effects, and which may interfere with the animal's ability to generate antibodies.
Genetic engineering allows scientists to find the genes which produce antigens. Scientists can "cut" these genes from an organism, and "glue" them to bacteria or other organisms. These organisms copy the necessary antigen in large quantities.
Genetically engineered vaccines have several advantages:
- They contain only the antigens necessary to produce the immune response. There are no unnecessary proteins which might interfere with that process.
- These antigens are purified from bacterial cultures, improving their safety and effectiveness.
- The vaccine can be tailored to overcome complicated disease processes.
- Tailored vaccines offer flexible vaccination times, so animals can be vaccinated when they are likely to be most vulnerable to disease.
Genetic engineering is also used in the creation of a new class of vaccines called immunopharmaceuticals. These vaccines stimulate the immune system to alter body functions. They:
- Provide humane alternatives to procedures such as castration.
- Improve productivity without compromising animal health.
Examples
Genetically engineered vaccines are providing safe, effective and humane answers to many animal health problems. Some examples are:
- Vaccines for shipping fever, and what is known as the Haemophilus somnus disease complex, were developed in Saskatchewan. Shipping fever is a common disease in cattle. A combination of four viruses and two bacteria lead to severe pneumonia and often death. The H. somnus disease complex is a common bacterial infection in cattle. It causes several conditions, including INFECTION OF THE HEART, pneumonia and arthritis. Development of these vaccines for cattle and calves led to similar vaccines for hogs.
- Development of a new vaccine will offer a humane way to improve egg production in breeding turkeys. The vaccine will stimulate the turkey's immune system to overcome the tendency to stop laying eggs.
- Beef and hog producers will soon have a vaccine alternative to castrating livestock. Bull calves are castrated to control aggression. Male pigs undergo the procedure to eliminate what is known as "boar taint", which makes the meat inedible. The new vaccine would render the animals sterile, and eliminate the need for surgery. The vaccine can be timed to ensure the animals grow well and use feed efficiently.
- Researchers are working on genetically modified crops to create edible vaccines for livestock. For example, pigs could be fed genetically engineered alfalfa that would stimulate immunity to a serious intestinal virus.
- Devastating livestock diseases in developing nations will soon be fought with genetically engineered vaccines. For example, researchers are working on a vaccine for an African cattle disease called East Coast fever, which is caused by a parasite known as a protozoa. If successful, this vaccine would be the first against a protozoan parasite. Its development could have implications for a malaria vaccine for humans.
For more information on biotechnology and animal health, please contact:
Saskatchewan Agricultural Biotechnology Information Centre (SABIC)
c/o Ag-West Biotech Inc.
101 - 111 Research Drive
Saskatoon, Saskatchewan Canada S7N 3R2
Telephone: 306-975-1939
Fax: 306-975-1966
E-mail: agwest@agwest.sk.ca
Web page: http://www.agwest.sk.ca
This project has been made possible with the support of the Canada-Saskatchewan Agri-Food Innovation Fund (AFIF)
Produced by: The Signature Group Inc., Saskatoon, SK