EN
The efficacy of zinc application in the treatment and prevention of diarrhoea in the weaning period of piglets has been demonstrated. However, beside this positive effect some authors suggested the possibility of harmful effects of zinc oxide supplementation on the environment and public health. The aims of the study were to evaluate, in experimental and field conditions, the influence of different doses of ZnO on productivity, losses and body weight gain (b.w.g.) as well as the Zn level in different tissues of pigs. During the first stage of the study three groups of weaned piglets were fed high doses (2 500, 3 000 and 3 500 ppm) of ZnO for 7 days prior to and 14 days after weaning. The best results were observed in the group fed with highest doses of ZnO, in this group daily b.w.g. was 26 grams higher in comparison with the controls. Tissue samples from muscles and selected organs (liver, kidneys, pancreas, heart and brain) were taken from experimental pigs at slaughter after the animals had reached a body weight of about 100kg. The results of toxicological examination indicated that 14-days of treatment with high doses of ZnO have no influence on zinc concentration in tissues. Field experiments aimed at safety and evaluation of the usefulness of ZnO on the prophylaxy of post weaning diarrhoea, performed in 8 farms, demonstrated reduction of diarrhoea symptoms from about 48 to 15%. In summary, it may be concluded that short-term application of ZnO in prevention of post weaning diarrhoea is efficient for pigs and does not influence zinc concentration the fatteners tissues.