ABSTRACT
It is evident that the microbiota, that is, the ecological community of commensal, symbiotic and pathogenic microorganisms, is immensely important to the host, particularly in the gastrointestinal tract (GIT). The microbiota, particularly bacteria, plays a part in key physiological processes and can affect or influence the host in many ways including prevention of establishment of pathogenic bacteria, modulation of the immune system (both systemically and at the level of the GIT), detoxification, production of vitamins and short-chain fatty acids and facilitation of digestion and absorption processes. The succession of the microbiota starts in the young pig during the birthing process and also immediately after birth, but changes rapidly in the period after weaning that is coincidental with the myriad of changes that occurs during this process (Frese et al. 2015). Antibiotics, especially the so-called antibiotic growth promotants (AGP) and/or minerals such as zinc oxide (ZnO) and/or copper sulphate (CuSO4), have been traditionally included in pig diets after weaning to help with the prevention and/or control of diseases such as post-weaning colibacillosis. However, due to concerns in relation to the development of antimicrobial resistance, as well as accumulation of minerals such as zinc in the environment, other strategies have been researched as either replacements or alternatives to AGP.
