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Centre for Genetic
Improvement of Livestock Transgenic Chickens Lay
Future Benefits |
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Transgenic technology is being used at a University of Guelph research laboratory to modify the normal antibiotic component of chicken eggs, for increased food safety and medical benefits. Prof. Ann Gibbins, Animal and Poultry Science, is working with research assistant Dr. Guodong Liu and graduate students Jan Losos and Gregory Lampard to create transgenic chickens with increased amounts and types of an antimicrobial protein called lysozyme. Lysozyme, normally found in egg white, protects the embryo within the egg from microbial contamination. In food processing, it is routinely isolated from eggs and used to enhance food preservation and prevent food contamination for everything from fish and cooked meats to toothpaste and mouth wash. "Lysosyme can selectively destroy certain harmful microorganisms while allowing beneficial bacteria to survive," says Gibbins. "There are tremendous market applications for this protein if its production could be increased." So researchers want to genetically engineer increased lysozyme levels in eggs, and broaden its effectiveness against more disease-causing and food-spoilage organisms. The Demand Is Increasing Canada produces about one-sixth of the world's supply of lysozyme from egg white proteins. But the demand is increasing rapidly. Lysozyme can also be modified to have a wider bacterial range against disease-causing or food-spoilage bacteria. This is of particular interest to the medical community where there's concern of pathogenic bacteria developing resistance to current antibiotics. Gibbins says novel lysozyme could act as an alternative antibiotic. Making Alterations Alterations to lysozyme are possible through transgenic animal lines. Transgenic animals such as sheep, fish and goats have been developed by researchers worldwide, but transferring genes to chickens has proven more difficult. This is mainly due to the hard eggshell which surrounds chickens' embryos, restricting access. |
Gibbins and her research team have been
working for 10 years to develop an effective technique for inserting
foreign material into chicken embryos. They have been successful in
producing transgenic birds using a method that involves a donor and
recipient egg. Cells from the donor embryo are mixed with the foreign gene
and then injected into the recipient embryo through a hole in its
eggshell. The embryo grows as a mixture of normal and modified cells -
called the chimeric intermediate - in hopes that its offspring display
the foreign genes.
A series of experiments by Gibbins and her team have begun, involving the insertion of extra copies of the lysozyme gene into chickens to improve lysozyme production. They're also inserting altered copies of the gene to produce a novel version of lysozyme. Potential transgenic birds are currently being analyzed, and their eggs will later be examined for the deposition of the increased or modified lysozyme. Commercially useful transgenic chickens should be available in the next five years. This research is sponsored by the Ontario Egg Producers' Marketing Board, Ontario Ministry of Agriculture, Food and Rural Affairs, Agriculture and Agri-Food Canada and the Natural Sciences and Engineering Research Council.
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