Materials and methods
2.1. Source and composition of REE-citrate
The product Lancer® 500, used in this study, consists of
50% wheat starch and 50% REE-citrate, whereby the lanthanoide
(REE-citrate) itself consists of 25.3% (growing period)
and 38.7% (fattening period) rare earth elements and 74.7%
and 61.3% citrate, respectively. The REE-citrate was a mixture
containing organic citrate compounds of 57.9% Ce, 34.0% La,
6.5% Pr and 1.6% of other rare earth elements (Lancer® 500
Zehentmayer AG Berg, Switzerland). In Switzerland, this
product is licensed as “lanthanoide” feed additive in complete
diets of piglets and fattening pigs.