The brain of fish, as in other vertebrates, is
responsible for many functions basic to life and is also thought to be an anoxia-sensitive tissue. Therefore, during
anoxia, the maintenance of energy within the brain is of
paramount importance to the survival of the animal. Studies
concerning energy levels and storage and the use of
anaerobic metabolism in fish brains following exposure to
anoxia are lacking.
Rainbow trout (Salmo gairdneri) and brown bullhead
catfish (Ictalurus nebulosus) occupy ecologically distinct
habitats. Their tolerance of anoxia is different; trout
survived l2 minutes while bullhead survived 62 minutes in anoxic water. Brains from control and anoxia—exposed trout
and bullheads were analyzed using enzymatic assays and high
pressure liquid chromatography (HPLC).
Control bullhead brains had higher concentrations of
glycogen, ATP, CrP, and glucose than control trout. With anoxia, bullheads showed a significant decrease in ATP,
CrP, and glycogen with no change noted for glucose, ketone
bodies (beta—hydroxybutyrate and acetoacetate), or
alternative anaerobic endproducts (succinate, alanine,
propionate, isobutyrate, isovalerate, and ethanol). Lactic
acid increased two-fold with anoxia. The bullhead was able
to generate ATP by depleting its CrP stores and through
classical anaerobic glycolysis. Death was most likely due
to an inability to maintain ATP levels. Catfish may survive
anoxia longer than trout in part due to greater fuel stores.
Rainbow trout brain stored approximately one—sixth the
amount of glycogen as bullheads. With anoxia, these stores
were depleted but there was no significant decrease in ATP,
CrP, or glucose; the alternative endproducts also did not
change. There was a l00% increase in lactic acid,
suggesting that anaerobic glycolysis helped maintain ATP
levels. Death may be due to factors other than ATP
depletion such as lactic acid injury and increased
intracellular free calcium.
next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
![[VT]](http://scholar.lib.vt.edu/images/ETD-db/restricted.gif)
