2005 Volume 40 Issue 2 Pages 47-51
In this study, we examined the effect of temperature shock on non-specific defense responses and disease resistance of rainbow trout Oncorhynchus mykiss. Water temperature was changed from 10°Cto 23°Cin 24h, maintained at 23°Cfor 7 days, and again decreased to 10°C in 1h. Percentage of phagocytosing phagocytes, NBT reduction activity, potential killing activity and plasma bacteriolysis activity were measured before, during and after the temperature changes. Just before the temperature was decreased to 10°C, fish were challenged with Vibrio anguillarum. Exposure to the temperature stress significantly increased mortality caused by vibriosis, but the percentage of phagocytosing phagocytes and potential killing activity significantly increased. The present data shows that increased non-specific defense responses in vitro do not always reflect increased disease resistance.
