Antibiotic growth promoters were supposed to increase growth rate as a result of improved gut health, resulting in better nutrient utilization and decreased feed conversion ratio However, there is the fear that the continuous subtherapeutic use of in-feed antibiotics could lead to the development of antibiotic resistant bacteria, which can be harmful to humans.
Thus, efforts have been made in different parts of the world to ban the inclusion of all types of antibiotic growth promoters in animal feeds.