Digestive Enzyme Secretion After Dietary Variation in the American Lobster (Homarus americanus)

American lobsters, Homarus americanus, were fed diets containing 0, 5, and 20% starch for periods up to 37 days. Digestive enzymes in the stomach juices of these and fasted lobsters were assayed. The base-line, or true fasting enzyme level was considered to be those values found after feeding for 2 days on a 5% starch diet. Compared to this basal level both specific activities and absolute amounts of proteinase, lipase and, to a lesser extent, amylase were found to rise on prolonged feeding. Further feeding (all diets) allowed products of a greater proportion of proteinase than amylase or lipase; alteration of the starch content of the diet had no consistent effect.