Thiamine (Vitamin B1) Deficiency in Fish and Wildlife

Science Center Objects

In the last few decades, thiamine deficiency has been observed in fish and wildlife in the Great Lakes, Alaska, Sweden and several other areas in North America and Europe. Thiamine is an essential vitamin needed for cell function. Thiamine deficiency has been linked to neurological disorders, immunosuppression, and lower reproductive viability. These disorders potentially reduce populations of affected species.  CERC scientists are developing methods to determine the thiamine status in fish and other wildlife and evaluating if populations are being impacted by this phenomenon.

The Issue:

Thiamine (Vitamin B1)

Thiamine (Vitamin B1), a water-soluble vitamin needed by all living cells.

(Public domain.)

Thiamine (Vitamin B1) is a water-soluble vitamin needed by all living cells. A phosphorylated form, thiamine diphosphate, is a cofactor essential for at least five life-sustaining enzymes used for cellular metabolism. Most animals acquire thiamine through their diet, so thiamine deficiency can arise if food is thiamine deficient. Additionally, some prey species produce large amounts of thiaminase, which breaks down thiamine in the predators that eat them. Again, this leads to thiamine deficiencies in predators.  

When a deficit of thiamine occurs, the effects have been linked to lower reproduction, decreased viability of early life stages, neurological disorders, immunosuppression, and ultimately declines in certain fish and wildlife populations in the Northern Hemisphere. This phenomenon has been observed in wild populations of fish, birds, reptiles and possibly mammals. Wildlife potentially impacted are analyzed at CERC to determine thiamine status in these populations.


Addressing the Issue:

CERC scientists, along with collaborating institutions, routinely collect biological samples from areas in the Great Lakes and Alaska, where wildlife is impacted by thiamine deficiency.

CERC scientists have: 

  • Determined the thiamine status of forage fishes and wildlife in the Great Lakes region.
  • Described the effects of thiamine deficiency on vision, growth, foraging ability, and predator avoidance in fry of lake trout and other salmonids.
  • Evaluated thiamine levels and fatty acid composition of salmon and trout eggs from the Great Lakes.
  • Evaluated the occurrence and activity of thiaminase (a thiamine degrading enzyme) found in certain aquatic food web species.

Data generated from these investigations are routinely shared and presented to the scientific community and policy makers.


Frozen Lake Trout eggs being weighed for a thiaminase assay

Frozen Lake Trout eggs being weighed for a thiaminase assay.

(Credit: Diane Nicks, USGS. Public domain.)


Next Steps/Future Steps/Results:

CERC scientists are continuing these studies to monitor thiamine status in at-risk wildlife populations and to identify past and future trends and potential causes of thiamine deficiency. Thiaminase levels are also monitored in prey species to better understand dietary thiaminase as a cause of thiamine deficiency in predators.  




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