The aerobic capacity of tunas: Adaptation for multiple metabolic demands

, corresponding to 2.8 times the RMR. When converted to its energy equivalent, total magnitude of SDA was linearly correlated with ration size to a maximum of 192·kJ·kg -1 ·h -1 , and as a proportion of gross energy ingested (SDA coefficient), it averaged 35±2.2%. These results demonstrate that, although the factorial increase of SDA in SBT is similar to that of other fish species, the absolute energetic cost of SDA is much higher. These results support the contention that tuna are energy speculators, gambling high rates of energy expenditure for potentially higher rates of energy returns. The ration that southern bluefin tuna require to equal the combined metabolic costs of SDA and RMR is estimated in this study to be 3.5%M b of Australian sardines per day.

Section: Sda and Metabolic Scopesupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

The energetic consequence of specific dynamic action in southern bluefin tunaThunnus maccoyii

Fitzgibbon

Seymour

Ellis³

et al. 2007

“…Fish must be able to multitask and partition the oxygen available between competing processes (Korsmeyer et al, 1996), and Pauly (Pauly, 1998) concluded that fish have to 'choose' to allocate the limited oxygen they have to fuel either a higher growth rate or a greater performance. Thus, given their higher standard and routine M O 2, our adult GH transgenic salmon appear to be favouring growth, at the expense of maximum performance (as evidenced by their 9% lower U crit ).…”

Section: Table·6 Heart Chamber Morphometrics Of Transgenic and Contrmentioning

confidence: 99%

Cardiorespiratory modifications, and limitations, in post-smolt growth hormone transgenic Atlantic salmonSalmo salar

Deitch

Fletcher

Petersen

et al. 2006

SUMMARY In recent years, there has been a great deal of interest in how growth hormone (GH) transgenesis affects fish physiology. However, the results of these studies are often difficult to interpret because the transgenic and non-transgenic fish had very different environmental/rearing histories. This study used a stable line of size-matched GH Atlantic salmon (Salmo salar) that were reared in a shared tank with controls (at 10°C, for∼9 months) to perform a comprehensive examination of the cardiorespiratory physiology of GH transgenic salmon, and serves as a novel test of the theory of symmorphosis. The GH transgenic salmon had a 3.6× faster growth rate,and 21 and 25% higher values for mass-specific routine and standard oxygen consumption (ṀO2),respectively. However, there was no concurrent increase in their maximum ṀO2, which resulted in them having an 18% lower metabolic scope and a 9% reduction in critical swimming speed. This decreased metabolic capacity/performance was surprising given that the transgenics had a 29% larger heart with an 18% greater mass-specific maximum in situ cardiac output, a 14% greater post-stress blood haemoglobin concentration, 5–10% higher red muscle and heart aerobic enzyme (citrate synthase or cytochrome oxidase) activities, and twofold higher resting and 1.7× higher post-stress, catecholamine levels. However, gill surface area was the only cardiorespiratory parameter that was not enhanced, and our data suggest that gill oxygen transfer may have been limiting. Overall, this research: (1) shows that there are significant metabolic costs associated with GH transgenesis in this line of Atlantic salmon; (2) provides the first direct evidence that cardiac function is enhanced by GH transgenesis; (3) shows that a universal upregulation of post-smolt (adult) GH transgenic salmon cardiorespiratory physiology, as suggested by symmorphosis, does not occur; and (4) supports the idea that whereas differences in arterial oxygen transport (i.e. cardiac output and blood oxygen carrying capacity) are important determinants of inter-specific differences in aerobicity, diffusion-limited processes must be enhanced to achieve substantial intra-specific improvements in metabolic and swimming performance.

“…The most complete relevant body of data known to us based on the standard interpretation of respirometry measurement is for (smaller) yellowfin tuna, Thunnus R. M. Nisbet and others albacares (Dewar and Graham, 1994;Korsmeyer et al, 1996;Korsmeyer and Dewar, 2001). These indicate: standard metabolic rate (11%), average contribution from aerobic swimming (27%), oxygen debt recovery (38%), SDA (18%) and growth (6%).…”

Section: Example: Pacific Bluefin Tunamentioning

confidence: 99%

Integrating dynamic energy budget (DEB) theory with traditional bioenergetic models

Nisbet

Jusup

Klanjšček

et al. 2012

127

There was an error published in the online (Full Text and PDF) version of J. Exp. Biol. 215,[892][893][894][895][896][897][898][899][900][901][902] In Table 3 (p. 896), a typographical error was introduced into Eqns A3 and A4 during the production process. The correct version is given below.We apologise to all authors and readers for any inconvenience caused.This error does not occur in the print version of this article.