Avian Respiration

Abstract

It is important for members of the veterinary profession to have a reasonable understanding of avian respiration for the following reasons:

1. In the context of world agriculture, the economic importance of domestic avian species has shown a dramatic increase in recent years. In Britain alone poultry products were worth about £350,000,000 last year.
2. A number of serious respiratory diseases such as Newcastle disease, infectious bronchitis, infectious laryngotracheitis, psittacosis, avian influenza and aspergillosis affect poultry health and thus productivity and profitability. The importance of these diseases is obviously increased by modern methods of poultry husbandry by which 10,000 birds may be kept in the same house.
3. Poultry pathologists know a good deal about the virology and immunology of these diseases but for a balanced understanding of the situation, knowledge of the avian respiratory system is obviously an essential prerequisite.
4. For a really adequate understanding of any disease process, and here we are thinking of an avian respiratory disease, it should be possible to present a picture, well documented by experimental and clinical observation, of the cellular interaction between the pathogenic organisms and the infected tissues. With the electron microscope we should be able to illustrate these events from the initial invasion of the cells through destruction, to their final repair.
5. This ultrastructural picture should be paralleled by an equally detailed account of immunological responses, antibody formation and activity, systemic effects on feeding, sleeping, growth and the distribution both inside and outside the body of infective material that might cause the spread of the disease. It is probably true to say that no disease of any species, human, domestic mammal or bird, has so far been described with this degree of detail.

Avian respiration is worth studying for its own sake, because it is an intellectually rewarding thing to do. The avian respiratory system, as a piece of biological engineering, is quite different from the mammal and probably a good deal more efficient.

In this general account an attempt has been made to provide a simple introduction to the subject for those who may never have thought about it before; but at the same time to provide sufficient of the latest information for those who know much of it already.

References to specific research have been kept to a minimum but a few general publications, in addition to those quoted in the text, have been added at the end. Fortunately these are quite recent and so include reference to all but the very latest research.