Lobster Nutrition: The Effect on Homarus americanus of Dietary Protein Levels

Abstract

Adult American lobsters (Homarus americanus) were fed artificial diets ranging between 0 and 60% protein and made isocaloric by adjusting the content of cornstarch. Those fed the highest level of protein were in the best condition; each decrease in protein resulted in a poorer condition of the lobsters. When lobsters were fed diets at the maintenance level of 0.5% of the body weight in food per day, decreasing the dietary protein content resulted in increasing weight loss and decreasing molt incidence, serum protein content, percent edible meat, heart weight, hepatopancreas and gonad weights, and increased moisture content of several tissues. Although the serum glucose level was dependent upon the cornstarch content of the diet, the glycogen content of the hepatopancreas was not affected by dietary starch levels. The glycogen content of the hepatopancreas showed a very large range of values when protein was omitted from the diet.A relationship between serum calcium level and molt cycle was demonstrated. Serum calcium values went from an average of 50 mg% after molting to over 70 mg% 1 mo before molting.