Frequent incidence of postweaning enterotoxigenic Escherichia coli (ETEC) diarrhea in the swine industry contributes to high mortality rates and associated economic losses. In this study, a combination of butyric, caprylic, and capric fatty acid monoglycerides was investigated to promote intestinal integrity and host defenses in weanling pigs infected with ETEC. A total of 160 pigs were allotted to treatment groups based on weight and sex. Throughout the 17-d study, three treatment groups were maintained: sham-inoculated pigs fed a control diet (uninfected control [UC], n = 40), ETEC-inoculated pigs fed the same control diet (infected control [IC], n = 60), and ETEC-inoculated pigs fed the control diet supplemented with monoglycerides included at 0.3% of the diet (infected supplemented [MG], n = 60). After a 7-d acclimation period, pigs were orally inoculated on each of three consecutive days with either 3 mL of a sham-control (saline) or live ETEC culture (3 × 109 colony-forming units/mL). The first day of inoculations was designated as 0 d postinoculation (DPI), and all study outcomes reference this time point. Fecal, tissue, and blood samples were collected from 48 individual pigs (UC, n = 12; IC, n = 18; MG, n = 18) on 5 and 10 DPI for analysis of dry matter (DM), bacterial enumeration, inflammatory markers, and intestinal permeability. ETEC-inoculated pigs in both the IC and MG groups exhibited clear signs of infection including lower (P < 0.05) gain:feed and fecal DM, indicative of excess water in the feces, and elevated (P < 0.05) rectal temperatures, total bacteria, total E. coli, and total F18 ETEC during the peak-infection period (5 DPI). Reduced (P < 0.05) expression of the occludin, tumor necrosis factor α, and vascular endothelial growth factor A genes was observed in both ETEC-inoculated groups at the 5 DPI time point. There were no meaningful differences between treatments for any of the outcomes measured at 10 DPI. Overall, all significant changes were the result of the ETEC infection, not monoglyceride supplementation.
Keywords: Escherichia coli; inflammation; monoglycerides; pig.
Infection caused by the bacterium known as enterotoxigenic Escherichia coli (ETEC) is a common disruptor of weaned pigs’ health, leading to economic losses for the producers. To determine if nutritional supplementation could help protect against these losses, weaned pigs were assigned to one of three treatments: 1) uninfected and fed a standard nursery pig diet, 2) infected with ETEC and fed the same standard diet, or 3) infected with ETEC and fed the standard diet supplemented with a combination of butyric, caprylic, and capric fatty acid monoglycerides. Growth performance was tracked throughout the 17-d study and health outcomes were measured at the peak and resolution of ETEC infection. At the peak-infection time point, pigs that were infected with ETEC had lower fecal moisture content, greater fecal bacterial concentrations, and elevated body temperatures compared with uninfected pigs. Additionally, infection reduced expression of genes related to inflammation, angiogenesis, and the intestinal barrier during the peak-infection period. Overall, all significant changes were the result of the ETEC infection, and there were no meaningful differences observed between the different treatments.
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