Untersuchungen zum Einsatz Seltener Erden als Leistungsförderer beim Schwein

Studies on the effect of rare earth elements as growth promoter in pigs In China, rare earth elements were used in agriculture already for some decades. Rare earth elements are 17 elements which include scandium, yttrium, lanthanum and the 14 lanthanides. They were used as fertilizer in plant production and as growth promoters in animal production. Spectacular improvement of the fattening parameter daily body weight gain and feed conversion ratio of pigs were reported in the Chinese literature. In previous experiments of our working group the growth promoting effect of the rare earth elements has been proven for pigs under western feeding and housing conditions. In this thesis two feeding experiments with fattening pigs and a field trial with weaned piglets are described. In the first experiment a total of 48 pigs (German Landrace x Piétrain) were allotted to four dietary groups, 12 pigs in each group. The animals received a mixture of rare earth elements in a concentration of 0 or 300 ppm rsp. or pure lanthanum chloride and cerium chloride in a concentration of 100 ppm LaCl3 and 200 ppm CeCl3 or 200 ppm LaCl3 and 100 ppm CeCl3. Because of a disease this first study had to end ahead of schedule. In the second trial the design of the trial was the same as in the first one. During the 12 weeks of this experiment the pigs received feed, supplemented with the above described concentration of rare earth elements. The daily body weight gain in the REE group during the study period was 4 to 5 % better than in the control group, where there was no influence on the feed conversion rate. The accumulation of the lanthanides in the muscle and the liver was very low as shown in the experiments before. The analysis were made by ICP-mass spectrometry. In the serum, the levels of triiodothyronine and thyroxine were lower in the groups receiving the rare earth elements than in the control group. Thyroxine in the groups with 300 ppm REE mixture and with 100 ppm LaCl3 and 200 ppm CeCl3 was significantly lower than in the control group. In a field trial with piglets of the race Swiss Edelschwein the growth promoting effect of rare earth elements was proved by two experiments. The animals were fed with a commercial feed supplemented with a mixture of rare earth elements in a concentration of 0 rsp. 200 ppm. In the first trial for 16 days body weight gain and feed conversion ratio of the group with 200 ppm REE mixture improved by 3 % rsp. 9 % as compared to the controls. The second field trial lasted for 30 days and here, the group supplemented with 200 ppm REE mixture gained by 10 % more weight than the control group. The feed conversion ratio improved by 2 %. These results showed for the first time, that rare earth elements are able to improve the performance of the piglets under field conditions.

Level thesis:degree_level

thesis.doctoral

Grantor dc:publisher

Ludwig-Maximilians-Universität

Year

2003

Author dc:creator

• Eisele, Nicole

Repository record source_url

https://edoc.ub.uni-muenchen.de/1509/

OAI identifier oai:identifier

oai:edoc.ub.uni-muenchen.de:1509