Nutrient absorption, storage and remobilization in<i>octopus vulgaris</i>

Abstract

Abstract Average absorption and conversion to 14CO2for free leucine included in a meal were 96% and 30% after 24 h. The values for glucose were 98% and 48% and for palmitate 46% and 12.5%. Muscle was the major repository of leucine (38% of the total ingested) and glucose (44%), but the digestive gland contained most of the palmitate (20%). During normal feeding 14CO2 production from octopuses given leucine dropped to low stable levels after only 2 days, those given glucose required 4 to 5, but palmitate apparently did not enter a stable reserve. Fasting increased the release of 14CO2 from octopuses given palmitate and leucine, but glucose animals showed little change. A 5‐fold increase in 14CO2 production during forced exercise after fasting by octopuses given glucose may indicate increased carbohydrate catabolism. Reduced 14CO2production in exercise after other substrates is consistent with this, suggesting muscle carbohydrate reserves may be exclusively for locomotion. A comparison of nutrient uptake, catabolism and growth suggests that lipids are the limiting nutrient for octopuses on a crab diet. Notes To whom reprint requests should be directed.