Biotechnology in animal nutrition, physiology and health

Biotechnology is already widely used in animal production and there are numerous other potential applications. Application of biotechnology can be envisaged for improving the performance of animals through better nutrition, enhanced production potential or improved health status. Nutrients (i.e. amino acids) can be produced and/or protected, resulting in improved formulation of diets that more accurately meet specific needs for productive functions. Enzymes can improve the nutrient availability from feedstuffs, lower feed costs and reduce output of waste into the environment. Pre- and pro-biotics or immune supplements can inhibit pathogenic gut microorganisms or make the animal more resistant to them. Plant biotechnology can produce crops with improved nutritional value or incorporate vaccines or antibodies into feeds that will cheaply and effectively protect the animals against diseases. Transgenic manipulation of commensal gut or rumen microorganisms has considerable potential for improving nutrition, gut development and health in animals. Administration of recombinant somatotropin (ST) results in accelerated growth and leaner carcasses in meat animals and increased milk production in dairy cows. The effects on meat or milk quality are limited. Immunomodulation can also be used for enhancing the activity of endogenous anabolic hormones. Transfer of the ST gene has the same effects as use of exogenous ST. However, unless the expression of the gene is controlled with ad-hoc promoters, the health status of the transgenic animals is severely impaired. There are numerous applications of biotechnology that aim to improve the health and welfare of animals. The generation of disease-resistant transgenic farm animals is still a long-term goal. On the other hand recombinant vaccines are widely in use. New advancements such as DNA-based vaccines and genetically engineered vaccine adjuvants hold much promise for improving animal health. Monoclonial antibodies and nucleic acid probes are used widely in diagnostic tools. Neutralization approaches, including immunological and antisense DNA, can offer interesting alternatives to surgical castration and the traditional prevention of broodiness in breeder birds. Acceptance of biotechnology in livestock production is difficult, and depends heavily on the perception of risks and benefits by the general public. Information is critically important in order that lay citizens can make an educated choice. The acceptance of biotechnology applied to animal production will depend on social and cultural aspects, and on the perceived benefits for consumers and society in general. (C) 1999 Elsevier Science B.V. All rights reserved.