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United States Department of Agriculture

Agricultural Research Service

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Research Project: DOES THE INCLUSION OF DISTILLER DRIED GRAINS WITH SOLUBLES IN THE DIET OF PIGS AFFECT SUSCEPTIBILITY TO/COLONIZATION WITH SALMONELLA

Location: Livestock Behavior Research

2013 Annual Report


1a.Objectives (from AD-416):
To determine the effect of distiller dried grains with solubles (DDGS) inclusion in the diet on the susceptibility to, colonization with, and longitudinal shedding frequency and levels of Salmonella enterica in grow-finishing pigs.


1b.Approach (from AD-416):
This project will be conducted with the objective of determining if inclusion of DDGS in the diet of grow-finishing pigs affects their susceptibility to Salmonella as well as the colonization pattern of their intestinal tract and longitudinal shedding of Salmonella. Two experiments will be conducted to achieve this complex objective. In the first experiment, a total of 36 pigs (divided in two replicates or blocks) will be used to compare three treatments (Control/No DDGS, 20% DDGS, and 40% DDGS inclusion in the diet). After an adaptation period to the diets (1-2 weeks), pigs will be challenged with Salmonella enterica serovar Typhimurium resistant to nalidixic acid (10^4 CFU/pig). The start of fecal shedding of the bacteria will be monitored through individual fecal samples collected every 30 minutes for 6 hours. At 6 hours post-challenge, all pigs will be humanely euthanized and subjected to necropsy for sample collection (ileal contents, ileal tissue, mesenteric lymph node, cecal contents, and rectal contents). All samples will be analyzed for the frequency and levels of Salmonella to determine infection patterns. In the second experiment, a total of 40 pigs (divided in two replicates or blocks) will be used to compare two treatments (Control/No DDGS, and 30% DDGS inclusion in the diet). After an adaptation period to the diets (1-2 weeks), pigs will be challenged with Salmonella enterica serovar Typhimurium resistant to nalidixic acid (10^4 CFU/pig). Individual fecal samples will be collected every 48 hours to monitor the longitudinal frequency and levels of bacteria shedding (Salmonella and Escherichia coli) until 3 weeks post-challenge, when all pigs will be humanely euthanized and subjected to necropsy for sample collection (ileal contents, mesenteric lymph node, cecal contents, and rectal contents). Samples will be analyzed for the frequency and levels of Salmonella and Escherichia coli. Additionally, selected Escherichia coli isolates and intestinal content samples will be analyzed for antimicrobial resistance/susceptibility patterns and microbial diversity profiles, respectively.


3.Progress Report:

The objective of this project was to determine if a byproduct of ethanol production that is fed to swine, dried distillers grain and solubles (DDGS), would affect the amount of Salmonella in their intestines. Two experiments were conducted to accomplish the proposed objectives. In the first experiment, three treatments were compared, including: control (no DDGS), 20% DDGS and 40% DDGS inclusion in the diet. Six hours after the Salmonella challenge, it was observed that pigs receiving diet containing DDGS had a higher frequency of Salmonella shedding in their feces compared to pigs in the control group. In the second experiment, two treatments were compared, including: control (no DDGS) and 30% DDGS inclusion in the diet. Salmonella shedding was monitored longitudinally in both groups. It was observed that pigs receiving the control diet (no DDGS) had a higher frequency of Salmonella shedding in their feces at either 21 or 35 days post-challenge, compared to pigs receiving the diet containing 30% DDGS. There was no difference among treatments (in both experiments) on the levels of Salmonella shed in feces. It was concluded that pigs receiving DDGS in the diet are more susceptible to Salmonella within the first hours of exposure. However, the inclusion of DDGS in the diet decreased the long term colonization of the pigs with Salmonella. Thus, dried distillers grains with solubles can be fed to swine without increasing Salmonella infection in the long term.


Last Modified: 9/2/2014
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