Altering nutrient utilization in animals through transgenesis

Abstract

Improved domestic animal productivity is necessary in order to provide for an increasing world population over the next two to three decades and such improvement would be aided by an increase in the ef®ciency of nutrient utilization. This can be achieved by conventional genetic selection protocols but progress by this approach is slow. A more rapid but as yet largely unproven technique is the direct modi®cation of the genome which can be achieved by the transfer of recombinant DNA to the nuclei of early embryos. This new technology is potentially powerful because it allows the direct transfer of genes without regard to inter-species barriers to breeding. However, it raises a new set of problems associated with the integration and expression of the foreign genetic information in the new genome. In this review the application of the technology to increasing nutrient utilization and increased productivity are discussed. Two areas have received substantial attention in the 15 years since the technique was ®rst applied to domestic animals. First, the current status of the modi®cation of growth hormone levels to improve productivity and feed utilization ef®ciency is reviewed, with current results suggesting that several of the projects may soon be approaching ®eld trial status.

Potential of Nutrition in the Control of Growth and Meat Quality in Broilers.

“…Genetic modification might be anticipated even in relation to digestion and intermediary metabolism in animals. Ward (1999) reviewed recent studies directed towards the transfer of genes coding the biosynthesis of essential amino acids in animals, while no attempts have been reported in the literature concerning the modification of genes related to digestive function and intermediary metabolism in chickens. In mammals, cellulase mRNA was expressed in the pancreas and cellulase protein was shown to be secreted in the small intestine of transgenic mice (Hall et al, 1993).…”