Initial Palatability and Growth Trials on Pelleted Diets for Cephalopods

The palatability of frozen shrimp, live shrimp, live fish, fish fillets, surimi, raw chicken meat, pureed shrimp and chicken, turkey hot dogs and pellets formulated with penaeid shrimp, mysid shrimp and chicken, was tested on octopuses and cuttlefishes. The results of the octopus and cuttlefish palatability trials demonstrated that cuttlefishes took longer to grab all foods except live shrimp and fish than did the octopuses and neither ingested the surimi diets. The feeding responses of octopuses for pellets appeared to be most closely related to the moisture content of the pellets while cuttlefishes seemed to be less influenced by texture. Octopuses fed upon the penaeid and chicken pellets at the same rates (2.7–5.2% body weight·day⁻¹, % bw·d⁻¹) as live shrimp (4.9% bw·d⁻¹) and raw chicken (3.5% bw·d⁻¹), but only the latter diets promoted growth. Adult S. officinalis (124–465 g) survived and grew on penaeid pellets over 60 days, although there was substantial mortality by day 40 in group-reared cuttlefishes due to cannibalism. Feeding rates increased steadily from 1.0 to 3.5% bw·d⁻¹, although growth rates were about one-third to one-half that of cuttlefishes fed live shrimp. Juvenile cuttlefishes (14 g) ingested pellets routinely after 4 days and the feeding rates ranged 6.4–8.1% bw·d⁻¹. The cuttlefishes doubled their weight in 57 days although 7 of 20 were cannibalized. The moist, pelleted diet appeared to be palatable to both octopuses and cuttlefishes but the reduced growth rates for cuttlefishes and no growth exhibited by the octopuses fed the pellets suggest that nutritional deficiencies or imbalances exist. The results demonstrate that pelleted diets can be used to maintain cephalopods and modest growth can be expected at this stage of diet development. The disadvantages of lower growth rates are offset by the cost savings compared to expensive natural diets that require high labor costs for collection and maintenance.