The effect of temperature and starvation on the clearance of bacteria from the bloodstream of rainbow trout (Salmo gairdneri Richardson).

The blood clearance of 51Cr-labeled heat-killed Salmonella pullorum was generally biphasic and exponential for each phase. Starvation had little significant effect on this pattern, although the rate of first phase clearance was probably slower. Raising the water temperature from 8 degrees C to 18 degrees C enhanced the rate of clearance of the second phase to almost exactly double that at 8 degrees C. At 18 hr postinoculation, the spleen contained much more radioactivity per gm than any other tissue. This finding is in marked contrast to earlier work that showed that at 1 hr postinoculation, the kidney contained the most, and it suggests that redistribution of bacteria occurred. The most distinct effect of temperature stress on tissue localization of bacteria was in the heart: A rising temperature stress caused increased numbers of bacteria to localize within the heart. Less clear-cut changes were also seen in other tissues with different treatments. With the possible exception of starvation effecting a slower first phase clearance rate, we have been unable to demonstrate that the vascular clearance mechanisms, including the reticuloendothelial system, are significantly compromised by raising the water temperature or by starvation.