Present address: Departmento de Biotecnología Microbiana, Centro Nacional de Biotecnología, CSIC, Campus Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.
Determination of minimal concentration of Piscirickettsia salmonis in water columns to establish a fallowing period in salmon farms
Article first published online: 18 JAN 2010
© 2010 Blackwell Publishing Ltd
Journal of Fish Diseases
Volume 33, Issue 3, pages 261–266, March 2010
How to Cite
Olivares, J. and Marshall, S. H. (2010), Determination of minimal concentration of Piscirickettsia salmonis in water columns to establish a fallowing period in salmon farms. Journal of Fish Diseases, 33: 261–266. doi: 10.1111/j.1365-2761.2009.01119.x
- Issue published online: 9 FEB 2010
- Article first published online: 18 JAN 2010
- Received: 25 September 2008 Revision received: 8 March 2008 Accepted: 30 March 2009
- bacterial load;
- fallowing period;
- Piscirickettsia salmonis
A highly sensitive real-time PCR procedure to detect and quantify the number of Pisciricketsia salmonis units in seawater samples from affected farm sites has been developed. The purpose was to determine a fallowing period that would allow safe restocking of the target farm with new fish. Bacterial load was determined in water samples by comparing the obtained amplification values against a standard curve generated by the amplification of known concentrations of the ITS-ribosomal component of P. salmonis DNA, cloned in a suitable vector. The standard curve was linear over the range of 101–1010 log units. Target samples were taken every 10 days over a 40-day period, at 5 m depth and at the surface. In a highly affected area of southern Chile, the number of bacterial units in farm water decreased to zero at day 50. Therefore, a fallowing period of 50 days post-removal of cages of affected fish appears to be appropriate before restocking. This procedure could be adapted to control disease problems because of other pathogens in fish farm waters.