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The objectives of this study were to elucidate the effects of a dirty environment and a Salmonellachallenge plus associated environmental contamination on pig growth performance, diet utilization efficiency, and gas emissions (CO2, NH3, CH4, N2O, and H2S) from stored manure. Twenty-four weaned barrows, aged 31 d at initiation of the trial, were randomly allotted to 3 different treatments in a completely randomized design. Treatments were: pigs housed in cages with manure removed and cages washed daily (Clean); pigs housed in cages sprayed daily with manure slurry mixtures (Dirty); or pigs challenged with SalmonellaTyphimurium DT104 and housed in cages that were not washed, but manure was removed daily (Salmonellachallenge). Rectal temperature, body weight, daily feed intake, manure output, manure composition, and gas emissions from stored manure were measured throughout the 24-d animal phase. The Dirty and Salmonellachallenge treatments were statistically compared to the Clean treatment to evaluate individual effects. Dirty housing tended to decrease ADG from d 1 to 24 (P= 0.06) but there were no other effects on pig performance compared with the Clean treatment. In contrast, a Salmonellachallenge was associated with a marked reduction in each of the measured indicators of pig performance. Salmonellachallenge increased the carbon to nitrogen ratio, ether extract, and lignin concentrations in excreted manure (P= 0.02, 0.01, 0.003, respectively), and increased manure and head space temperatures in manure tanks (P< 0.0001). Gas emissions from stored manure of pigs on the Dirty or Salmonellatreatments were increased for each of the measured gases as compared to the Clean treatment (P< 0.01) when expressed per unit of BW gain. When gas emissions from manure of pigs housed in the Dirty treatment were expressed per unit of manure volatile solids (VS), they were increased for NH3, CH4, and H2S (P< 0.02). Salmonellachallenge was associated with increased emissions of CO2, and N2O and decreased emissions of H2S per kilogram manure VS compared to the Clean treatment (P= 0.06, 0.03, 0.04, respectively). Collectively, these results indicated that a Salmonellachallenge and associated housing contamination caused depressed growth rate and increased manure gas emissions, while exposure to a Dirty environment slightly reduced growth performance and clearly increased manure gas emissions per unit of BW gain as compared to Clean control.

Anaerobically fermented yeast products are a rich source of nutritional metabolites, mannanoligosaccharides, and β-glucans that may optimize gut health and immunity, which can translate into better growth performance and a reduced risk of foodborne pathogens. The objective of this study was to quantify the effects of Saccharomyces cerevisiaefermentation product (Diamond V Original XPC) inclusion in nursery diets on pig performance and gastrointestinal microbial ecology before, during, and after an oral challenge with Salmonella.Pigs (n = 40) were weaned at 21 d of age, blocked by BW, and assigned in a 2 × 2 factorial arrangement consisting of diet (control or 0.2% XPC) and inoculation (sterile broth or Salmonella). Pigs were fed a 3-phase nursery diet (0 to 7 d, 7 to 21 d, and 21 to 35 d) with ad libitum access to water and feed. On d 14, pigs were orally inoculated with 109cfu of Salmonella entericaserovar Typhimurium DT104 or sterile broth. During d 17 to 20, all pigs were treated with a 5 mg/kg of BW intramuscular injection of ceftiofur-HCl. Growth performance and alterations in the gastrointestinal microbial ecology were measured during preinoculation (PRE; 0 to 14 d), sick (SCK; 14 to 21 d), and postinoculation (POST; 21 to 35 d). Body weight and ADG were measured weekly. Rectal temperature (RT) was measured weekly during PRE and POST, and every 12 h during SCK. Diet had no effect on BW, ADG, or RT during any period (P= 0.12 to 0.95). Inclusion of XPC tended (P< 0.10) to increase Salmonellashedding in feces during SCK. Consumption of XPC altered the composition of the gastrointestinal microbial community, resulting in increased (P< 0.05) populations of Bacteroidetesand Lactobacillusafter Salmonellainfection. Pigs inoculated with Salmonellahad decreased ADG and BW, and increased RT during SCK (P< 0.001). Furthermore, fecal Salmonellacfu (log10) was modestly correlated (P= 0.002) with BW (r = −0.22), ADFI (r = −0.27), ADG (r = −0.36), G:F (r = −0.18), and RT (r = 0.52) during SCK. After antibiotic administration, all Salmonella-infected pigs stopped shedding. During POST, an interaction between diet and inoculation (P= 0.009) on ADG indicated that pigs infected with Salmonellagrew better when eating XPC than the control diet. The addition of XPC to the diets of weanling pigs resulted in greater compensatory BW gains after infection with Salmonellathan in pigs fed conventional nursery diets. This increase in BW gain is likely associated with an increase in beneficial bacteria within the gastrointestinal tract.