Lysozyme as an alternative to antibiotics in swine feed

Abstract Text: Antibiotics have been fed at subtherapeutic levels to swine as growth promoters for more than 60 years, and the majority of swine produced in the U.S. receive antibiotics in their feed at some point in their production cycle.  These compounds benefit the producers by minimizing production losses by increasing feed efficiency and decreasing susceptibility to bacterial infection and disease. However, many countries, including all of the European Union, have banned the use of antibiotics as growth promotants in animal agriculture.  Due to the perceived risk of bacterial resistance to antibiotics important in human medicine, swine producers are currently under tremendous pressure to eliminate subtherapeutic antibiotic use.  Recent Federal Drug Administration guidance (No. 209 and 213) are designed to limit the use of medically important antibiotics in animal agriculture in the U.S.  Lysozyme, also known as muramidase, is a naturally occurring enzyme found in bodily secretions such as tears, saliva, and milk and is a good replacement for traditional antibiotics.  It functions as an antimicrobial agent by cleaving the peptidoglycan component of bacterial cell walls, which leads to cell death.  While the mechanism by which antibiotics or lysozyme improve performance is not clearly understood, they improve gastrointestinal health, improve the metabolic profile, and alter the gastrointestinal bacteria ecology of swine. 

Keywords: Lysozyme, antibiotics, swine, gastrointestinal, microbiota