Alternatives to antibiotics in swine and poultry

Abstract Text: To reduce the risk for the spread of antibiotic resistant bacteria from livestock to humans, the European Union banned the use of antibiotics as growth promoters in animal feeds for pigs and poultry since January 2006. As a result, the use of veterinary prescribed antibiotics increased in a sort of compensation phenomenon. In intensive husbandry systems, veterinary prescribed antibiotics are mainly used around birth and in new-born animals.

To study the effects of antibiotic usage during early life stages, we performed several experiments in piglets and poultry. We analysed both the short-time and long-term effects at the level of intestinal microbiota and intestinal mucosal functions. To this end, we applied metagenomics, transcriptomic and immunologic analytical approaches on intestinal tissues and luminal contents, taken at different intestinal locations and at different time-points after treatment. These studies clearly demonstrated both short-term and long-term effect on the expression of immune related genes. We hypothesized that that these long-lasting effects are due to differences in the programming of the gut immune system as induced by the temporary early life perturbation of the gut microbiota.

In order to search for alternatives for antibiotic growth promoters, a large variety of farming approaches are proposed, including organic acids, probiotics and prebiotics, enzyme, clays and minerals, trace elements, and botanicals. In this presentation, we will show the effect of the administration of fructooligosaccharides (FOS) to suckling piglets on intestinal microbiota and gene expression. Twelve days of intervention with FOS resulted in a bifidogenic effect in the colon of treated piglets. Furthermore, after 23 days of intervention with FOS, decreased expression in immune related gene sets was observed in treated piglets.

In this context, it is also  important to identify major intrinsic and extrinsic factors that (co)determine the early life gut microbial colonization of livestock species. From literature it is already known that several extrinsic factors are important, including the sow/mother-hen and the environment. Here we show data that indicate that also the genetic make-up of host is an important factor in the early life microbial colonization of the gut and consequently for immune system development.

In conclusion, during early life, the interplay between the host (genetics), environment (nutrition and/or management), in association with the microbiota modulate bacterial colonization, drives gut development and immune maturation. The use of antibiotics during early life stages perturbs this interplay significantly with serious consequences for the functionality of the host immune system.

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