Wild birds of declining European species are dying from a thiamine deficiency syndrome

Abstract

Wild birds of several species are dying in large numbers from an idiopathic paralytic disease in the Baltic Sea area. Here, we demonstrate strong relationships between this disease, breeding failure, and thiamine (vitamin B1) deficiency in eggs, pulli, and full-grown individuals. Thiamine is essential for vertebrates, and its diphosphorylated form functions as a cofactor for several life sustaining enzymes, whereas the triphosphorylated form is necessary for the functioning of neuronal membranes. Paralyzed individuals were remedied by thiamine treatment. Moreover, thiamine deficiency and detrimental effects on thiamine-dependent enzymes were demonstrated in the yolk, liver, and brain. We propose that the mortality and breeding failure are part of a thiamine deficiency syndrome, which may have contributed significantly to declines in many bird populations during the last decades.␣-ketoglutarate dehydrogenase ͉ avian ͉ extinction ͉ transketolase

Reply to Rocke and Barker: The question is not whether birds are affected by thiamine deficiency or botulism, it is about the order of events

“…Contrary to the suggestion by Rocke and Barker (1), we do not want to exclude botulism as a part of the investigated wildlife disorder (2), because botulism may be secondary to the thiamine deficiency syndrome. This possibility and the investigations by Neimanis et al (3) (5), and the actual sensitivity in the study by Rocke et al (5) was 35 out of 40 (88%), which is considerably higher than the proportion found among Swedish gulls (3,4).…”

“…The omission of four thiamine-treated specimens in the evaluation of the herring gull experiment is carefully and very well motivated (2). Even if this procedure is not accepted, and all specimens are included in the evaluation, there is still a highly significant therapeutic effect of the thiamine treatment [Fisher's exact test, P = 0.0012; our Table S2 (2)].…”

An Exploratory Assessment of Thiamine Status in Western Alaska Chinook Salmon (Oncorhynchus tshawytscha)

“…Likewise the eff ect of variable thiaminase activity on thiamine concentrations in juvenile Chinook or coho salmon has not been determined. Therefore knowledge of thiamine and thiaminase activity of potential prey items is important information, not only for Alaskan salmon species, but also for other top predators found to have low thiamine (Balk et al 2009).…”

“…Despite diff erences among species, a common theme has been observed when thiamine defi ciency is present. This often includes reproductive failure, a decline in populations, and multiple hypotheses off ered to explain the reproductive failures observed (see Hill and Nellbring 1999;Brown et al 2005b;Honeyfi eld et al 2008b;Balk et al 2009).…”

Road to regulation of endocrine disruptors and combination effects

“…Andersen and co-workers (Andersen et al, 2012, Wohlfahrt-Veje et al, 2011, 2012aand 2012b demonstrated that exposure of mixtures of pesticides used under regulatory approved situations results in reproductive disorders among greenhouse workers but the main drivers for these effects could not be established. In other cases adverse effects are caused by currently unidentified chemicals (Balk et al, 2009;Fitzsimons et al, 2001). In addition, there are few examples where major contributors of the toxic potential in complex mixtures are identified, and numerous investigations have demonstrated that other substances than those we generally analyze are major contributors (Brack, 2003).…”