Reduced environmental pollution
The most significant risk with ZnO use is the environmental impact. Manure from pigs supplemented with ZnO contains higher levels of Zn. This manure is used as fertilizer, spread on to fields which then releases Zn into the soil and groundwater where Zn concentrations rise to dangerously high levels for wild animals and plants.
Less antimicrobial resistance
Numerous investigations have also shown that pharmacological levels of ZnO supplementation in piglets can contribute to antibiotic resistance. ZnO can also influence the microbiota composition in piglets by reducing Lactobacillus species and increasing Clostridiales and Enterobacteriales diversity.