Antibiotics as Growth Promotants:mode of Action

Abstract

Recent concerns about the use of growth-promoting antibiotics in pig diets have renewed interest in the immunologic and growth-regulating functions of the gastrointestinal (GI) tract. The numerically dense and metabolically active microbiota ofthe pig GI tract represents a key focal point for such questions. The intestinal microbiota is viewed typically as a beneficial entity for the host. Intestinal bacteria provide both nutritional and defensive functions for their host. However, the host animal invests substantially in defensive efforts to first sequester gut microbes away from the epithelial surface, and second to quickly mount immune responses against those organisms that breach epithelial defenses. The impact of host responses to gut bacteria and their metabolic activities require special consideration when viewed in the context of pig production in which efficiency of animal growth is a primary objective. Here, we summarize the working hypothesis that antibiotics improve the efficiency of animal growth via their inhibition of the normal microbiota, leading to increased nutrient utilization and a reduction in the maintenance costs ofthe GI system. In addition, novel molecular ecology techniques are described that can serve as tools to uncover the relationship between intestinal microbiology and growth efficiency.

Excretion masses and environmental occurrence of antibiotics in typical swine and dairy cattle farms in China

“…Antibiotics are used extensively in animals to treat, prevent microbial infections and promote growth (Cromwell, 2002;Gaskins et al, 2002;Kummerer, 2009;Sarmah et al, 2006). In China, 210,000 tons of antibiotics are produced every year, of which 48% is applied in agriculture and livestock industry .…”

Effect of Probiotics, Garlic and Neem Leaf Powder Supplementation on Feed Efficiency in Caged Broiler

“…The routine uses of low-doses or subtherapeutic-levels of antibiotics often referred to as Antibiotic Growth Promoter (AGP) in broiler feed have been a common practice for more than 50 years to prevent potential disease as well as to robust gut health, increase meat yield and improve feed efficiency of broilers (Gaskins et al, 2002).…”

Trends in the occurrence of human and veterinary antibiotics in the sediments of the Yellow River, Hai River and Liao River in northern China

“…Antibiotics are used extensively in humans and animals to treat microbial infections, and also as feed additive to promote growth of livestock animals (Cromwell, 2002;Gaskins et al, 2002;Sarmah et al, 2006;Kummerer, 2009). In the United States, the annual usage of antibiotics are approximately 22 700 tons and 13067 tons are administered for animals, agriculture and aquaculture (FDA, 2009;Kummerer, 2009).…”