Minerals are essential trace elements for the survival of horses and other animals, but they can be toxic when too much is ingested.
Researchers in Italy set out to learn more about the levels and potential bioaccumulation of vanadium, chromium, cobalt, copper, zinc, cadmium, lead and bismuth in horses in an industrial risk area of Sicily.
The University of Messina study team analyzed samples taken from 20 horses at an equine center near Milazzo.
Milazzo has a high degree of pollution because of the presence of large refinery plants and other industrial operations.
Recent studies had reported mercury bioaccumulation in blood and serum samples of horses in this area, Francesco Fazio and his colleagues noted in their report in the open-access journal, Animals.
They took samples to determine the distribution and concentration of the mineral elements in whole blood, serum, tail and mane hairs in horses. Samples of hay, concentrate, and water were also analyzed.
The authors found that the minerals were distributed unevenly in the horses across the biological samples taken.
The concentrations of vanadium, copper, zinc, and cadmium showed significantly lower values in serum samples compared to whole blood, and were higher in the tail compared to the mane.
The authors noted that copper and zinc are important micro-elements for animals and humans, but can be toxic in excessive amounts.
The results showed higher copper and zinc concentrations in whole blood than the serum, mane and tail hairs, and copper content in serum was affected by areas and seasons. In each biological material tested, the average copper concentrations were within the normal range expected for horses.
Zinc content in whole blood samples was statistically higher than in serum, tail, and mane samples. Zinc levels were found to be higher than reference values defined for horses in 1992. The authors say the bioaccumulation of this element in the horses could be due to various factors, and probably indicates smoke from galvanizing operations.
Cadmium showed statistically significantly higher values in whole blood than the other tested biological samples.
Higher cobalt values were found in the tail samples.
Chromium did not vary significantly in whole blood, serum, and mane samples, while in the tail, the values were significantly higher than for all the other samples. No chromium reference values are available for horses.
Lead levels were higher in the whole blood and serum when compared to the hair samples.
The concentrations of Bismuth found in the samples did not represent a toxicological risk for the studied horses, the team said.
The concentrations of the mineral elements present in the hay and concentrate fed to the horses were found to be below the limits established by the European Commission, and were under potentially toxic intake levels reported for horses.
The authors said that while blood and serum are widely used in monitoring studies for these elements, new biological samples such as hair could represent a valid alternative.
However, further investigations are needed involving other species and using different biological samples in order to have complete “body mapping” of the bioaccumulation of different essential trace elements.
The full study team comprised Fazio, Enrico Gugliandolo, Vincenzo Nava, Giuseppe Piccione, Claudia Giannetto and Patrizia Licata.
Fazio, F.; Gugliandolo, E.; Nava, V.; Piccione, G.; Giannetto, C.; Licata, P. Bioaccumulation of Mineral Elements in Different Biological Substrates of Athletic Horse from Messina, Italy. Animals 2020, 10, 1877.