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Title: Enterobacteriaceae levels in finishing pigs subjected to a ractopamine feeding program

item Rostagno, Marcos
item Marchant, Jeremy

Submitted to: International Pig Veterinary Society (IPVS)
Publication Type: Proceedings
Publication Acceptance Date: 4/21/2008
Publication Date: 6/22/2008
Citation: Poletto, R., Rostagno, M.H., Richert, B.T., Marchant Forde, J.N. 2008. Enterobacteriaceae levels in finishing pigs subjected to a ractopamine feeding program. In: Proceedings of the 20th International Pig Veterinary Society International Congress. Vol 1. P.224.

Interpretive Summary:

Technical Abstract: Food safety concerns regarding potential effects of feed additives are currently at the center of the public/consumer attention. Ractopamine (RAC) has been widely used in the U.S. swine industry for its effects of improving production performance in finishing pigs. Although extensive research has been conducted on the growth performance and carcass benefits of using RAC, scarce information is available on its physiological consequences, and almost no information is available on the effects of this additive on intestinal microbial populations. The objective of this study was to determine the effect of a RAC feeding program on Salmonella frequency and total Enterobacteriaceae levels during the last 4 weeks of the finishing production stage, and at slaughter. A total of 64 animals were assigned to 16 pens (4 pigs/pen), equally divided as either control (CTL; no RAC added to the diet) or RAC treatment (5 ppm for 2 weeks, followed by 10 ppm for 2 weeks). Individual fecal samples were collected weekly, and at slaughter, individual cecal and rectal contents were collected. Pigs fed RAC had significantly higher average body weight at slaughter compared to CTL pigs (P<0.001). No Salmonella was found in any of the samples collected during the study. Pigs receiving RAC in the diet had a peak of Enterobacteriaceae shedding levels at the first week of feeding, but progressively decreased up to slaughter (P<0.05). Although Enterobacteriaceae shedding levels were numerically higher for RAC pigs for all weekly fecal samplings, at slaughter, cecal and rectal levels of Enterobacteriaceae were significantly lower compared to CTL pigs (P<0.05). Decreasing the amount of potentially pathogenic bacteria entering the abattoir may contribute to reduce the risk of carcass contamination. Therefore, based on our results, further research about the effects of RAC on intestinal microbial populations in swine is warranted.