Bacterial composition changes in response to zinc oxide within the gastrointestinal tract of newly weaned pigs until 28 days post-weaning

摘要

Determining changes within the bacterial composition of healthy pigs in response to zinc oxide is the first step to uncovering the mode of action of zinc oxide in newly weaned pigs.In pig production, weaning is associated with nutritional and environmental changes for the pig. These sudden changes result in microbial alterations within the gastrointestinal tract (GIT) and can provide an opportunity for pathogenic colonisation, often from enterotoxigenic Escherichia coli (ETEC), leading to post-weaning diarrhoea (Fairbrother et al., 2005). The supplementation of zinc oxide at pharmacological levels (2.5 g/kg) immediately post-weaning reduces diarrhoea (Feng et al., 2006) and improves performance of pigs during this critical stage (Miller et al., 2009). However, antibiotic resistance and environmental concerns have led to the ban of pharmacological levels of ZnO in weaner pig diets from 2022 (Rajput et al., 2018; Vahjen et al., 2015). Pressure is now increasing to find sustainable alternatives to ZnO, but to do this, the mode of action of ZnO could prove essential to identify changes that are leading to the improved health and performance currently seen. The aim of this study wasto identify key changes in the bacterial composition of the ileum, caecum and colon of pigs receiving 2.5 g/kg ZnO vs a control diet at weaning and at 14 and 28 days post weaning.