Effect of sublethal concentrations of four chemicals on susceptibility of juvenile rainbow trout (Oncorhynchus mykiss) to saprolegniosis
The effects of sublethal concentrations of a variety of chemicals on the susceptibility of rainbow trout (Oncorhynchus mykiss) juveniles to Saprolegnia parasitica infection was examined. Sublethal concentrations of un-ionized ammonia (0.05 mg/liter) and nitrite (0.12 mg/liter) increased fish susceptibility after 10 days of exposure to the toxin, this increase being higher for ammonia (75% and 20% morbidity) than for nitrite (20% and 0% morbidity, respectively) with inoculum doses of 1.4 x 106 and 9.5 x 105 zoospores per liter, respectively. Sublethal concentrations of copper (0.05 mg/liter) or cyanide (0.05 mg/liter) did not show enhancement of infection by S. parasitica, even though the toxin exposure was for 21 days and the inoculum doses were higher than those for the experiments with the nitrogen compounds (4 x 106 and 3.2 x 106 zoospores per liter. However, infections began to appear in control animals.
| Main Authors: | , |
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| Format: | journal article biblioteca |
| Language: | English |
| Published: |
American Society for Microbiology
1991
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| Online Access: | http://hdl.handle.net/20.500.12792/5734 http://hdl.handle.net/10261/295131 |
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