Piglet weaner diets are often supplemented with the antimicrobial mineral zinc oxide (ZnO) to minimise the characteristic growth check post weaning in commercial systems. Zinc has been shown to decrease the incidence of scours, maintain gut morphology and feed intake, and increase growth rate, although the mechanism for these effects remains unclear. Weaning is often accompanied with a decrease in digestive enzyme production by enterocytes, decreasing digestive and absorptive capacity. Digestive enzyme requirements also alter with the dietary change from milk to a solid cereal-based diet, and improvements in enzymatic adaptations may increase digestion and absorption and improve feed utilisation. It is hypothesised in this study that the growth effects of ZnO are linked to improvement in digestion by altering digestive enzyme expression and activity. The aim of this study was to investigate whether the effects of ZnO are linked to expression of the digestive enzymes lactase phlorizin hydrolase (LPH) and aminopeptidase N (ANPEP) in the small intestine (S.I.).