Effects of dietary trimethylamine on the alkaline phosphatase and reductase activities in the guppy, Poecilia reticulata, in relation to seawater adaptation

Abstract

1. 1. Alkaline phosphatase activity of the digestive tract of seawater-adapted guppies was about three times as large as that of freshwater fish and was affected more markedly by salinity and pH of the reaction medium. Administration of 223μM trimethylamine per kg dry weight of diet was most effective for enhancing the enzyme activity. 2. 2. The reductase activity of cytochrome oxidative enzyme system of the gill was larger in seawater fish. The salinity dependency of enzyme activity was remarkable and the optimum salinity was distinctly higher in seawater fish. The effect of dietary trimethylamine was also evident. © 1980.