Biotechnology in the potential practical application of somatotrophic hormones for improving animal performance

The use of biotechnology now allows adequate supplies of previously scarce substances. This has enabled evaluation of some of these substances as enhancers of animal performance. Growth hormone (GH) shows promise as a stimulator of lactation in a number of species, but its effects on the stimulation of growth are somewhat equivocal. Somatocrinin, by virtue of its GH- releasing activity, may also be potentially useful, though to date the effects of somatocrinin administration have been less promising than those for GH directly. Somatomedin (IGF-1), as the active mediator of GH, might be expected to be useful in growth promotion but, as yet, it has not been convincingly demonstrated to stimulate growth in normal animals. All these hormones have the major drawback that, until a suitable slow-release/delivery mechanism is available, they need to be administered very frequently. An alternative approach, immuno-neutralization of the growth inhibiting effects of somatostatin, has been demonstrated to enhance growth; although at present still requiring multiple treatments such a technique potentially has many advantages.