Tel.+49 30 838 52256 Fax.+49 30 838-55938
Dietary zinc oxide (ZnO) shows beneficial effect on E. coli induced diarrhea in pigs after weaning, but no data is available on the bacterial development directly after weaning. Twenty weaned piglets were fed diets containing 150 or 3000ppm Zn from standard ZnO sources and 150 or 300ppm Zn from a commercial ZnO preparation. Daily fecal samples were used to detect a range of relevant enterobacterial genes via PCR assays. The development of the Escherichia group (measured by 16S rDNA) showed an increase until 4 days after weaning in pigs fed the 150ppm Zn diets, followed by a drastic decline until day 10. However, the 300ppm as well as the 3000ppm diets showed an earlier decline already 2 days after weaning, which led to less colonization of the Escherichia group than in the other trial groups. The most prevalent toxin gene was the E. coli estIIb. Contrary to the colonization of enterobacteria, a severe decrease of the amount of estIIb genes was visible in animals fed the 3000ppm diet already after the first day after weaning. A decline was observed in all other trial groups. Generally, the impact of dietary Zn was lessened in all experimental groups 14 days after weaning. In conclusion, this study showed an immediate effect of ZnO ranging from 3 to 4 days after weaning until 8 to 10 days after weaning.