Whole blood manganese concentrations in anaemic dogs with inflammatory bowel disease or confirmed iron-deficiency anaemia

Objectives: Manganese is an essential trace element, however, excess manganese leads to neurotoxicity in many species. Dietary Mn is efficiently adsorbed through the gastrointestinal
tract via divalent metal transporter 1 (DMT1) which is also responsible for iron transport. DMT1 is upregulated in iron deficiency and iron-deficiency anaemia has been associated with
increased manganese concentrations in humans with reports of resultant neurotoxicity. The goal of this study was to evaluate if manganese concentrations in anaemic dogs with inflammatory bowel disease or confirmed iron-deficiency were elevated compared to non-anaemic ill or healthy controls.
Methods: Manganese concentrations were determined by graphite furnace atomic absorption spectrometry in whole blood anticoagulated with ethylenediaminetetraacetic acid, from 36 dogs: 11 anaemic with inflammatory bowel disease, 4 anaemic with iron-deficiency, 9 non-anaemic ill controls, and 12 healthy controls. Mann–Whitney U-test and Kruskal–Wallis test with posttest Dunn’s multiple comparisons tests were performed, with P<0·05 considered significant.
Results: Manganese levels were significantly different between the four groups (P=0·0005) and overall higher in non-anaemic than anaemic dogs (P=0·0078). Manganese concentrations were also higher in healthy compared to ill controls (P<0·0001), anaemic dogs with inflammatory bowel disease (P=0·0056) and to anaemic dogs with iron-deficiency (P=0·0011). No differences were observed between anaemic dogs with inflammatory bowel
disease, iron-deficiency anaemia and ill controls.
Statement: This study did not support the hypothesis that iron deficiency anaemia increases whole blood manganese concentrations. Further research is warranted to understand the influence of anaemia on whole blood manganese.