In China, for 40 years Rare Earth Elements (REE) are used as growth promoters in
animal production. In recent studies of our group, we were able to show that there
are really ergotropic effects in piglets and in pigs, also when the animals are housed
and fed under our western condition. We found an increase of daily weight gain up to
12 % and feed conversion improved too. With this knowledge in mind, we became
interested in the question, if phytogenic supplements in combination with REE might
influence growth parameteres in piglets synergistically. Two phytogenic compounds
were used alone or in combination in several feeding studies.
The first feeding experiment was done with 96 piglets of the species Deutsche
Landrasse X Pietrain, 12 animals per group. Over a period of ten weeks each group
has been fed either a mixture of REE (as chloride, concentration of 0 respectively
300 mg per kg feed) and / or two different phytogenic supplements (concentration of
500 respectively 900 mg per kg feed). A small positive effect of 4% has been
observed under the supplementation of REE.
A second experiment has been done with 48 piglets (n=6 in the control, n=7 in the
treatment groups). The pigs have been fed over a period of six weeks the same
concentrations of REE and the two ergotrope additives as in test one. Under the
influence of REE (as citrate) and / or phytogenic additives an effect on growth and
feed conversion ratio become evident, however due to heavy diarrhoea, these data
have to be looked at cautiously.
During the third feeding experiment, lasting seven weeks, 42 piglets grouped into six
groups, have been fed a mixture of REE (as citrate, concentration of 0 respectively
200mg per kg fed) and / or the two phytogenic additives (concentration of 500
respectively 900 mg per kg feed). All five groups showed an effect on the feed
conversion. The intensity of the effect was not constant over the whole time of the
experiment. During the second and third week, the stongest effects have been
observed. Feed conversion improved by 19% in this time period. Looking at the
whole seven week period there was still a 9 % better feed conversion.
REE as well as the phytogenic growth promoters have been shown to have a positive
impact on feed conversion, but this effect was not statistically significant. An additive
effects of REE in combination with phytogenic compounds has not been observed.