Concentrations of trace elements in the diets and slurry of fattening pigs, sows and piglets

The objective of this study was to characterise the trace element composition of diets and slurry of pigs at different ages.Slurry was collected in stainless steel tanks placed under the slatted floors of the pens housing each group of pigs.The results show that the dietary concentrations of iron, copper, zinc, manganese, cobalt and selenium covered the recommendations of the INRA (1989). They were even supplied in excess of recommendations, copper was found at 12 times the recommended dietary level for piglets and for fattening pigs (122 and 116 ppm vs. 10 ppm, respectively).All trace elements were detected in the slurry of at least one of the pig groups, the only exception was mercury. Pig slurry appears to be especially rich in copper and zinc: 742 and 1886 mg/kg DM in piglet slurry, 837 and 1301 mg/kgDM in fattening pig slurry, respectively. These concentrations are not considered to be a cause of pollution based on the decree published on the 8th January, 1998. For the other heavy metals, slurry concentrations were below the maximum permitted levels when compared to all existing legislation. If legislation concerning heavy metals in pig slurry is introduced and becomes more restrictive, it will be necessary to reduce the concentrations allowed in feed.