Energy metabolism of fish under cold stress
Date Issued
1998-07-31
Date
1998-07-31
Author(s)
郭欽明
DOI
872311B002026B28
Abstract
Tilapia is one of economically important
culture species in Taiwan, and its culture
industry has contributed significantly to the
national economic development. Since tilapias,
a tropical species which are known less tolerant
to the cold, are suitable for culture in the warm
season of the year, mass mortality has often
occurred in the winter when the cold front
prevails, and consequently resulted in
catastrophic loss in the industry. The objectives
of this research are aimed to comprehend the
physiological responses, energy metabolism
mechanisms , expression and biological
functions of cold-shock proteins in order to
develop reliable technology for improved cold
tolerance of commercial important cultured
species, tilapia. The achievements will
certainly contribute tremendously to sustained
growth of aquaculture industry in this country.
Diversification in temperature tolerance and
adaptation mechanisms in teleosts have been
evolved from species differences in temperature
niche. The temperature compensation
mechanisms, species- specific under a defined
temperature environment, enable fish by its
capacity adaptation to maintain physiological
homeostasis, but in adverse environment, a
strategy of resistance adaptation is unanimously
followed for survival and propagation.
The behavioral responses and energy
consumption for temporal thermal acclimation
and the metabolic process, among others, for a
long-term adaptation are reliable indicators to the
state of thermal compensation towards
physiological homeostasis. Alternation in key
enzyme activities and metabolic pathway have
been the general paradigm of thermal acclimation
and adaptation at the subcellular levels.
Hyperglycemic responses of tilapias were
clearly demonstrated at 15 °C. The blood glucose
content was markedly elevated from 42.89 mg/dl
to 88.09 mg/dl in 2 hr. Similarly, the cold
toerant grass carps at 12 °C showed the increase
in the blood glucose from 62.44 mg/dl to 93.35
mg/dl in 6 hr, and the responses were much
pronounced in tilapias than grass carps. In
contrary, the blood glucose increased from 42.89
mg/dl to 57.26 mg/dl in 1 hr for the tilapias at 10
°C, which believed a low lethal limit of this
species, evidences suggested that tilapias have
shown a sign of physiological exhausion
resulting from the degration of regulatory
capabilities under this particular temperature.
Hyperglycemia is therefore concluded to be a
general stress response in fish, and the difference in the hyperglycemic response reflects a speciesspecific
difference in the thermal tolerance. A
significant elevation of blood lactate was only
detected in the tilapias at 10 °C, but not in other
treatments. This suggests that lactate is
produced through anaerobic metabolic pathway
to meet a burst demand in the energy source
under the extreme thermal condition. Finally,
the oxygen consumption is a reliable indicator
for physiological conditions of fish, and the trend
of changes in the oxygen consumption was found
highly correlated with the temperatures and the
duration of sustained stimulation.
Subjects
Cold temperature adaptation
Energy metabolism
Cold shock protein
SDGs
Publisher
臺北市：國立臺灣大學漁業科學研究所
Type
journal article
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