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Physiological alterations following severe hypoxic stress in two species of fresh-water fish

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Title Physiological alterations following severe hypoxic stress in two species of fresh-water fish
Names Heath, Alan G. (creator)
Pritchard, Austin (advisor)
Date Issued 1963-08-05 (iso8601)
Note Graduation date: 1964
Abstract Bluegill sunfish, Lepomia macrochirus, and cutthroat trout,
Salmo clarki, were exposed to a rapidly declining oxygen tension
for a period of time sufficient to just cause loss of equilibrium in
the fish. During recovery from the stress, measurements of
oxygen uptake, blood lactic acid, blood glucose, liver glycogen,
muscle glycogen, and hemoglobin or red blood cell counts were
made at fixed intervals of time.
Hypoxic stress caused an immediate rise in blood lactate and
oxygen uptake in both species with the trout showing the greatest
increases. This suggests a greater degree of oxygen debt in the
latter, even though the stress routine used on this species was not
as prolonged. A delayed peak in the blood lactate observed in the
trout but not in the bluegill indicated a possible impairment of circulatory
function in the former. The blood lactate returned to
normal after two and five hours in the bluegill and cutthroat respectively.
The return of the oxygen uptake to control levels required
eight and ten hours respectively.
An immediate mobilization of the carbohydrate stores
occurred during the stress in both the bluegill and trout. The blood
glucose concentration rose greatly in the bluegill but not in the trout.
Mobilization of liver glycogen in the trout without a concomitant rise
in glucose suggested utilization of the latter as rapidly as it was
formed. During recovery from the hypoxic stress, resynthesis of
glycogen stores occurred much more quickly in the bluegills than
trout.
Significant changes in hemoglobin or red blood cell numbers
did not occur in either species indicating no change in blood water
content, or effect on hemopoetic tissues resulting from the stress.
It was concluded that the differences observed between these
two species point to possible mechanisms in the bluegill which help
it to tolerate acute hypoxic conditions better than the trout.
Genre Thesis/Dissertation
Topic Fishes -- Physiology
Identifier http://hdl.handle.net/1957/48749

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