Efficacy of octopus feed encased within a collagen membrane

A feeding method suitable for rearing octopuses was investigated by preparing basic feed (ground crab or squid meat) enclosed within a collagen casing. Growth was compared between basic feed sealed in the casing and feed provided without a casing. No difference in growth was observed when the feed was squid, but with crab meat, both feeding efficiency and weight gain rate tended to be improved by encasement. When feeding on encased feed, octopuses were observed to feed not only by consuming the entire casing membrane, but also by eating only the edible portion inside the casing. Feed that was about to be eaten by octopuses was collected and measured for the enzyme activity associated with the feed, detecting protease activity, which is considered to be derived from the posterior salivary glands. It was concluded that encasement of feed in a collagen membrane not only improves the retention of soft feed materials within the membrane, but also suppresses the dispersal of enzymes when the octopus feeds, thus enabling the octopus to feed more efficiently.