BIOAV AILABILITY AND INTERACTIONS OF METALS VIA THE GASTROINTESTINAL TRACT OF RANBOW TROUT (Oncorhynchus mykiss)
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Date
2005-09-30
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McMaster University
Abstract
Knowledge into uptake rate and interactions of the metals via the gastrointestinal tract
of freshwater fish is vital, in order to provide tools to protect and to sustain aquatic biota.
An in vitro stomach and gut sac technique was utilized to investigate uptake rates of
essential metals (copper, zinc and nickel) and non-essential metals (cadmium, lead and
nickel) at luminal concentrations of 50fJ.M via the gastrointestinal tract Metals had no
effect on the fluid transport rates via the gastrointestinal tract except for copper at the
stomach. The stomach emerged as small but important site for metal absorption and
interaction. Essential metals were absorbed at approximately the same rate as nonessential
metals via the gastrointestinal tract. Copper, zinc, nickel, silver, and lead
showed statistical correlation between rate of absorption and mucus binding via
gastrointestinal tract, an important first finding for the development of a Biotic Ligand
Model (BLM) for the gastrointestinal tract of trout.
There was an antagonistic effect of calcium on cadmium uptake at the stomach but not at
the intestine. Zinc and calcium exhibited synergistic interaction at the stomach but no
interaction at the intestine. These results showed the possibility of the transporters DMTl
to mediate copper and cadmium uptake via the intestine; hZip 2 to mediate copper and
zinc uptake at the stomach; and Mzip 4 or ZTLl to mediate zinc uptake via the
gastrointestinal tract of trout. These results can be used to develop a BLM for the
gastrointestinal tract of fish.
Description
Staff Masters Thesis