Growth Promotion in Livestock

MSI Principal Investigator Richard Isaacson (Veterinary and Biomedical Sciences) is using MSI resources as part of his investigations into antibiotics that are used as growth promoters in livestock. Antibiotics have been used in this way for decades, but we don’t know the mechanism by which they promote growth. It is possible that this result is from the control of bacterial growth in the animals’ intestines, or because the antibiotics control specific bacterial populations in the intestinal tract. Recently, there are concerns that the use of these antibiotics may be eliminated or reduced in the future.

These researchers are using a molecular epidemiology approach to see if eliminating the use of these antibiotic growth promoters affects, for better or worse, the health of swine. Another goal is to see whether antibiotic growth promoters mediate their effects by alteration of microflora. They use software available through MSI to generate the data and then to analyze it. Besides various software packages, the group makes use of the Galaxy analytical framework.

Professor Isaacson and members of his research group, including fellow MSI Principal Investigator Srinand Sreevatsan (Veterinary Population Medicine) published a paper concerning this work in the Proceedings of the National Academy of Science in Fall 2012: “Microbial Shifts in the Swine Distal Gut in Response to the Treatment With Antimicrobial Growth Promoter, Tylosin,” HB Kim, K Borewicz, BA White, RS Singer, S Sreevatsan, ZJ Tu, and RE Isaacson, PNAS, 109:15485, DOI: 10.1073/pnas.1205147109 (2012). The figure above shows an analysis that used the Ribosomal Database Project (RDP) classifier to show the composition of the fecal microbiome of pigs receiving tylosin (an antimicrobial growth promoter) and those that did not, and how it changed over time. The graphs show results for treated (T) and non-treated (NT) pigs at different ages at two different farms. (A) RDP classification of the sequence reads from farm 1. (B) RDP classification of the sequence reads from farm 2.

Professor Isaacson and his group also use MSI for other projects, including investigations into the effect of pathogenic bacteria on the gut microbiome and analysis of the human lung microbiome (see “The Lung Microbiome in Moderate and Severe Chronic Obstructive Pulmonary Disease,” AA Pragman, HB Ki, CS Reilly, C Wendt, RE Isaacson,” PLos One, 7:e47305, DOI: 10.1371/journal.pone.0047305 (2012)). 

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