Effect of dietary d-amino acids on growth, survival, ammonia excretion and specific dynamic action in the supralittoral isopod, Ligia pallasii

Abstract

1. 1. Growth, survival, ammonia excretion and Specific Dynamic Action (SDA) were assessed in the supralittoral isopod Ligia pallasii eating chemical diets with differing proportions of d- and l-amino acids. Growth and survival decreased in direct proportion to increasing dietary intake of d-amino acids. 2. 2. Survival on diets with greater than 50% content of d-amino acids (based on total amino acids in diet) was lower than that expected based on previous work, suggesting a deleterious effect of the d-isomers. 3. 3. Ammonia excretion and SDA correlated negatively with increasing dietary content of d-amino acids. 4. 4. The general conclusion is that d-amino acids play no role in anabolic or energy metabolism in Ligia, and that poor performance at higher dietary levels of d-amino acids may relate to their interference with transport pathways for the normal l-forms.