Dietary utility of Chilean fish meal and pollack liver oil for juvenile Pacific bluefin tuna
2007
Takii, K.(Kinki Univ., Uragami, Wakayama (Japan). Fisheries Lab.) | Seoka, M. | Ohara, N. | Nasu, T. | Oda, S. | Miyashita, S. | Ukawa, M. | Shimeno, S. | Hosokawa, H.
Dietary utility of Chilean fish meal (FM) and pollack liver oil (PLO) for juvenile Pacific bluefin tuna Thunnus orientalis were investigated to develop their artificial diet. Diets 1, 2 and 3 were composed of 73, 63 and 53% FM and 0, 10 and 20% PLO, respectively. Control diet was raw sand lance (SL) Ammodytes personatus, with 77.6% crude protein and 6.2% crude lipid. Duplicate groups of juvenile tuna, weighing 1.68 g, were fed each diet until apparent satiety 6 times daily for 10 days. The diets and SL led low survival of tuna, due to flash collision against the tank walls. As compared with SL, diets 1-3 sustained lower daily intake and specific growth rate. Reversely, diets 1-3 led higher feed efficiency, protein efficiency ratio, apparent protein retention, final carcass crude protein content, entero-somatic index, and gastral peptic and enteral tryptic enzyme activities. Final carcass lipid and hepato-somatic index of tuna fed diets 2 and 3 were higher than those fed diet 1 and SL. These results suggest that FM in diet is a less digestible protein source for juvenile tuna, while the amino acid balance of FM sustains their requirements due to better protein retention than SL.
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