Using salt-enriched diets to reduce stress-induced hypochloremia and methemoglobinemia in rain[b]ow trout

Chronically stressfiil conditions in fish culture facilities can lead to outbreaks of disease and reductions in growth and performance. A secondary response to stress in fish is the sudden and significant loss of plasma chloride ions, a condition known as hypochloremia. This loss of plasma chloride has been implicated as a cause of mortality in severely stressed fish. The effect of increased dietary salt on reducing hypochloremia in rainbow trout subjected to a confinement challenge was investigated. Experimental diets included added NaCl or added CaClz. Methemoglobinemia, an environmental disease of cultured fish caused by increases in nitrite concentrations in water can be reduced by the addition of salt to water. Increased dietary salt as either NaCl or CaClz was investigated as an aid in reducing the development and severity of methemoglobinemia in trout exposed to elevated nitrite concentrations.