Antibiotics in animal nutrition

Antibiotics are natural or synthetic chemical substances that block the growth of cells. Antibiotics, specifically antimicrobial drugs, are commonly used in food-producing animals to treat, prevent and control disease, as well as to improve growth and feed efficiency. The exact mechanisms by which antibiotics improve these parameters are not well understood, but may include suppression of subclinical infections, changes in the abundance and/or composition of the intestinal microbiota, reduction of growth-depressing microbial metabolites in the intestinal tract, reduction of nutrient utilization by intestinal microorganisms, as well as increased nutrient uptake through a thinner intestinal wall. The overuse of antibiotics in animal farming is thought to have led to an increased prevalence of antibiotic resistance in several pathogens, some of which can represent a threat to human welfare. The potential association between antibiotic use in animal farming and a spread of pathogens with antibiotic resistance to human populations has prompted the use of other types of feed additives, such as probiotics, prebiotics or a combination of both. The economic impact of banning subtherapeutic use of antibiotics is huge, an estimate in 2001 calculated $242.5 million in swine production in the United States, with consumers sharing about 75% of these costs in the long run. More efficient strategies are needed to meet the nutritional needs of an always growing human population while at the same time avoiding and/or preventing the spread of multiple drug resistance in pathogenic organisms. The study of metabolic pathways for antibiotics in the host and the resulting consequences for human populations can help design better strategies to be used in farm animals. © 2013 by Nova Science Publishers, Inc. All rights reserved.