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Postprandial metabolic increment of southern bluefin tuna Thunnus maccoyii ingesting high or low-lipid sardines Sardinops sagax

journal contribution
posted on 2023-05-17, 01:18 authored by Quinn FitzgibbonQuinn Fitzgibbon, Seymour, RS
This study examined the postprandial metabolism and swimming speed of southern bluefin tuna Thunnus maccoyii when fed sardines Sardinops sagax of either high-lipid and high-energy content or low-lipid and low-energy content. Five groups of two or three T. maccoyii (mean ±s.e. mass = 19·8 ± 0·5 kg, n = 14) were fed either low [2·2% lipid, 5·5 MJ kg−1 gross energy (GE)] or high-lipid (12·9%, 9·2 MJ kg−1 GE) S. sagax. Before feeding, T. maccoyii swam at 0·74 ± 0·03 body lengths s−1 (n = 5) and their routine metabolic rate was 305 ± 15 mg kg−1 h−1. Swimming speed and metabolic rate of T. maccoyii increased following feeding. Thunnus maccoyii swam 1·3 and 1·8 times faster during digestion of low and high-lipid S. sagax, respectively. Postprandial peak metabolic rate, duration of elevated metabolism and total postprandial metabolic increment were all greater for T. maccoyii that ingested high-lipid S. sagax. When total postprandial increment is represented as a proportion of ingested energy, there was no difference between high and low-lipid meals, equating to between 30 and 35% of ingested energy. It was estimated that increased postprandial swimming costs account for 25 and 46% of the total postprandial metabolic response for low and high-lipid S. sagax meals, respectively. Specific dynamic action (SDA) accounts for c. 20% of ingested energy regardless of S. sagax lipid level. These results confirm that the postprandial metabolic increment of T. maccoyii is greater than most other fish species. Much of the high cost of postprandial metabolic increment can be attributed to increased postprandial swimming costs. For T. maccoyii, it appears that activity and SDA are not independent, which complicates bioenergetic evaluation. High postprandial metabolic costs accentuate the great energetic requirements of T. maccoyii

History

Publication title

Journal of Fish Biology

Volume

75

Issue

7

Pagination

1586-1600

ISSN

0022-1112

Department/School

Institute for Marine and Antarctic Studies

Publisher

Wiley Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

The definitive published version is available online at: http://interscience.wiley.com

Repository Status

  • Restricted

Socio-economic Objectives

Aquaculture tuna

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    University Of Tasmania

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