A cholesterol-enriched diet enhances egg production and egg viability without altering cholesterol Content of biological membranes in the copepod Acartia hudsonica.

Abstract Copepods may lack the capacity for de novo synthesis of cholesterol, while at the same time their dietary levels of sterol vary. We tested the hypothesis that copepods maintain the cholesterol contents of their biological membranes despite varying dietary levels of cholesterol. Acartia hudsonica were acclimated for 5 d to phytoplankton alone or phytoplankton supplemented with cholesterol, at a level sufficient to induce a maximal response on egg production rates. Biological membranes were prepared from the copepods and cholesterol contents assayed. Egg production and hatch rates were measured (the former to confirm that supplemented cholesterol was being assimilated). Analyses of marker enzymes indicate that the majority of membrane‐associated cholesterol in the copepod resides in the plasma membrane. In membranes fractions, cholesterol normalized to protein or activity of Na+/K+‐ATPase is not significantly different for supplemented and unsupplemented groups (29 and 33 μg cholesterol mg−1 protei...