Choline metabolism and nutritional requirement of lake trout (Salvelinus namaycush)

Duplicate lots of 2-g lake trout (Salvelinus namaycush) were fed a purified diet alone and with equimolar supplements of aminoethanol, methylaminoethanol, dimethylaminoethanol, choline or betaine. Supplements of choline, methyl- and dimethylaminoethanol significantly increased growth rate and reduced liver fat content, whereas aminoethanol and betaine did not. These results suggest that trout biosyn-thesize choline from methyl- and dimethylaminoethanol but not from aminoethanol or betaine.

In another experiment triplicate lots of 5-g trout were fed diets containing graded levels (0, 500, 1,000, 2,000 and 4,000 mg/kg) of choline. Growth results showed that the requirement for choline is no greater than 1,000 mg/kg of diet.