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Energy partitioning in cultured juvenile P acific bluefin tuna, T hunnus orientalis ( T emminck & S chlegel, 1844)
Author(s) -
Ohnishi Takayuki,
Biswas Amal,
Kaminaka Kohshi,
Nakao Takahiro,
Nakajima Masashi,
Sakakibara Noboru,
Takii Kenji
Publication year - 2016
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.12658
Subject(s) - thunnus , biology , juvenile , zoology , tuna , fishery , energy metabolism , metabolic rate , fish <actinopterygii> , ecology , endocrinology
The characteristics of dietary utilization, energy conversion efficiency, metabolic rate and energy partitioning were measured for cultured Pacific bluefin tuna ( PBT ) juveniles fed on an artificial diet. Thirty‐one juveniles (1.1 ± 0.3 g BW ) were stocked into each of two 2500 L tanks to measure oxygen consumption (ḾO 2 ), swimming speed, digestibility and growth performance. ḾO 2 elevated until 2.5 ± 0.3 times of pre‐feeding level within 1.5 h after feeding, except for the first feeding, and returned to pre‐feeding level within 3 h. Swimming speed fluctuation was corresponded with the ḾO 2 fluctuation, and both parameters were stable from 02:00 to 06:00 and also during the whole day for starved fish. These indicate that feeding has strong influence on their metabolic rate. Energy partitioning for faecal, urinary and branchial, heat increment and voluntary activity, standard metabolism, and retained energy were calculated to be 17.2%, 5.9%, 14.9%, 41.3% and 20.7% of total ingested energy, respectively. The results indicate that, unlike other fish, juvenile PBT distribute large amount of energy for maintenance, which allows only a little proportion of ingested energy available for growth.