The objective of this research is to identify natural feed additives that can be used in diets for newly weaned pigs to avoid the use of antibiotic growth promoters. APPROACH: Two experiments are proposed to evaluate the use of essential oils of herbs and spices for their possible use as feed additives in diets for newly weaned pigs. Herbs and spices that have previously been used in human medicine will be used. In the initial test, a wide range of herbs and spices will be screened in vitro for their antimicrobial activities against the most common pathogens. Following this screening, combinations of oils that - based on the results of the first screening - are anticipated to work synergistically will be tested in a similar way. The four most promising candidates or combinations will then be selected and tested in an in vivo experiment with pigs. Pig performance, intestinal integrity and morphology, intestinal ecology and the development of the immune system will be measured in this experiment. Results will be compared to results obtained in pigs fed diets containing a traditional antibiotic growth promoter. At the end of the experiment, products that can potentially replace antibiotic growth promoters will be identified. NON-TECHNICAL SUMMARY: Antibiotic growth promoters are used in diets for newly weaned pigs, and may increase the risk of transmitting antibiotic-resistant bacteria from livestock to the human food chain . It is anticipated that this experiment will identify natural products that can effectively replace antibiotic growth promoters in diets for newly weaned pigs. If successful, the use of antibiotic growth promoters in diets for pigs can be discontinued and thus, the risk of transmitting antibiotic-resistant bacteria from livestock to the human food chain will be reduced. If this objective is achieved, safer and more natural food products can be produced and the sustainability of modern livestock production will be enhanced.
Keywords: essential oils; herbs; spices; pigs; antibiotic-resistance; food safety
