6
Trace mineral status and toxic metal accumulation in extensive and
intensive pigs in NW Spain
======================================================
The aimof the present studywas to determine trace element status and toxicmetal accumulation
in extensive and intensive pigs in NWSpain. Soil, feed and animal tissues (liver, kidney and muscle
from 112 pigs) were collected from extensive and intensive pig farms across NW Spain and
analysed formetals by ICP-MS and ICP-OES. Our results indicate that animals fromboth extensive
and intensive systems showed an adequate mineral status and that toxic metal residues were
generally low, no sample exceeding the maximum admissible levels in meat and meat products
established by the EU. Trace element concentrations were generally higher in the intensive pigs
possibly reflecting mineral supplementation in the concentrate feed. The statistically significantly
higher As, Hg and Pb residues as well as the better Fe and Ni status in extensive pigs could be
related at least in part with soil ingestion when rooting. On the contrary, the higher Cd accumulation
in the intensive pigs can be explained considering Cu and Zn supplementation in the concentrate
feed. Our results also seem to indicate that toxic metal accumulation as well as trace
element status in different tissues could be related to metabolic aspects (i.e. related to breed
and growth rate) as well as certain management practices (i.e. physical exercise when grazing).