Q-02-09-001
Evaluation of effects of low-phosphorus diets on immune system function

In recent years, little or no research has been conducted to examine the impact of low-phosphorus feeds on immune system function and disease resistance in fish. Most references in the literature on phosphorus deficiencies in fish feed refer only to skeletal and/or developmental abnormalities and the objective of the research was to assess the phosphorus content required to avoid such abnormalities in salmon and carp and to obtain maximum weight gain over time. When low-phosphorus feeds are optimized for growth, they may not be optimized for maximum immune system performance. The objective of this project is to evaluate the immune system response in fish fed feeds containing different concentrations of phosphorus. To this end, fish from two groups, one receiving low-phosphorus feed and the other a feed with a standard concentration of phosphorus, will be exposed to Aeromonas salmonicida to assess the effect of the feeds on mortality in each of the experimental groups.

By examining how phosphorus affects the immune system in vivo, it will be possible to gain a better understanding of this relationship and to refine low-phosphorus commercial feeds available to freshwater fish farmers. This will enable fish farmers to produce fish stocks that are not only less polluting, but that will remain in better health during the production cycle.

Project Start Date: September 1, 2003

Project Completion Date: March 31, 2006

For further information please contact: Regional ACRDP Coordinator: Charley Cyr (E-mail: CyrCh@dfo-mpo.gc.ca).