Feed Additives and Feeding Strategies to Replace Antibiotics

Piglets are highly susceptible to enteric disorders immediately after weaning. Piglets have then an immature digestive system, whose capacity for nutrient digestion is impaired by the transition from high quality liquid milk to a solid diet. Diarrhea is common post-weaning and is characterised by reduced digestive capacity in young pigs leading to poor growth performance (Pluske et al., 1997). Because of an immature intestinal immune system, proliferation of enteropathogenic bacteria has a high incidence that further predisposes piglets to enteric infections. To mitigate these effects, weaned pigs are fed complex diets based on costly ingredients like processed blood proteins and milk by-products. Pig starter diets are also routinely supplemented with subtherapeutic levels of antibiotics as growth promoters (de Lange et al., 2010). However, public pressure is increasing to eliminate animal by-products and antibiotics from swine diets for fear of risks to human health and, in case of antibiotics transfer of antibiotic-resistant bacteria to humans. These concerns have sparked considerable interest in identifying alternative nutritional strategies for managing newly-weaned pigs fed antibiotic-free diets. Non-use of antibiotics in swine feeding programs has an added advantage as a marketing tool as several major international markets continue to demand pork products originating from pigs raised under such production systems.