**The title, authors, and abstract for this completion report are provided below. For a copy of the completion report, please contact the GLFC via e-mail or via telephone at 734-662-3209**
THIAMINE DEFICIENCY COMPLEX WORKSHOP
Final Report of the Research Coordination
Meeting on Thiamine Deficiency
November 6-7, 2008
Ann Arbor, MI
Dr. Dale C. Honeyfield, U. S. Geological Survey, Northern Appalachian
Research Laboratory, Wellsboro, PA, USA
Dr. Donald E. Tillitt, U. S. Geological Survey, Columbia Environmental
Research Center, Columbia, MO, USA
Dr. Stephen C. Riley, U. S. Geological Survey, Great Lakes Science
Center, Ann Arbor, MI, USA
Abstract:
Fry mortality which was first observed in the late 1960s in Great Lakes
salmonines and in Baltic Sea salmon in 1974 has now
been linked to thiamine deficiency (historically referred to as Early Mortality
Syndrome, or EMS and M74, respectively). Over the past 14 years significant
strides have been made in our understanding of this perplexing problem. It is
now known that thiamine deficiency causes embryonic mortality in these
salmonids. Both overt mortality and secondary effects of thiamine deficiency are
observed in juvenile and adult animals. Collectively the morbidity and
mortality (fry and adult mortality, secondary metabolic and behavior affects in
juveniles and adult fish) are referred to as Thiamine Deficiency Complex (TDC).
A workshop was held in Ann Arbor, MI on 6-7 November 2008 that brought together
38 federal, state, provincial, tribal and university
scientists to share information, present data and discuss the latest
observations on thiamine status of aquatic animals with thiamine deficiency and
the causative agent, thiaminase. Twenty presentations (13 oral and 7 posters)
detailed current knowledge. In Lake Huron, low alewife Alosa
pseudoharengus abundance has persisted and egg
thiamine concentrations in salmonines continue to
increase, along with evidence of natural reproduction in lake trout Salvelinus namaycush.
Lake Michigan Chinook salmon Oncorhynchus tshawytscha appear to have a lower thiamine requirement
than other salmonids in the lake. Lake Ontario American eel Anguilla rostrata foraging on alewife have approximately one
third the muscle thiamine compared to eels not feeding on alewife, suggesting
that eels may be suffering from thiamine deficiency. Secondary effects of low
thiamine exist in Great Lakes salmonines and should
not be ignored. Thiaminase activity in dreissenid mussels is extremely high but
a connection to TDC has not been made. Thiaminase in net plankton was found
more consistently in lakes Michigan and Ontario than other lakes evaluated. The
biological role of thiaminase I, associated with thiamine deficiency, remains
to be determined whereas thiaminase II has been reported to be part of a
salvage pathway leading to thiamine synthesis. The use of gene array technology
and 3-dimensional histology is adding new understanding to the affects of
thiamine deficiency. Research is needed to determine the thiamine status of
species feeding on dreissenids, the environmental sources of thiaminase and the
biological role of thiaminase I.