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ARS Home » Plains Area » Lubbock, Texas » Cropping Systems Research Laboratory » Livestock Issues Research » Research » Publications at this Location » Publication #325212

Research Project: Improving Immunity, Health, and Well-Being in Cattle and Swine

Location: Livestock Issues Research

Title: Sexually dimorphic innate immune responses but not tissue Salmonella translocation patterns in pigs exposed to an oral Salmonella challenge

Author
item Sanchez, Nicole
item Broadway, Paul
item Carroll, Jeffery - Jeff Carroll
item Gart, Elena - Texas A&M University
item Bryan, Laura - Texas A&M University
item Lawhon, Sara - Texas A&M University

Submitted to: Journal of Animal Science
Publication Type: Abstract Only
Publication Acceptance Date: 1/8/2016
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Sexually dimorphic innate immune responses have been observed in several species, but have not been studied in response to a live pathogen challenge in pigs. This study aimed to elucidate sexually dimorphic innate immune responses along with Salmonella translocation patterns in newly weaned pigs orally inoculated with Salmonella. Newly weaned pigs (n=8 gilts and 12 barrows; 6.2+/-0.2 kg body weight) were obtained from a commercial swine facility and were maintained in an environmentally-controlled facility in individual pens equipped with feeders and nipple waterers. Pigs were allowed ad libitum access to a commercial non-medicated starter ration and water throughout the study. On day 12, pigs were anesthetized to allow placement of a temperature measuring device (TEMP) in the abdominal cavity. On day 17, pigs were anesthetized and fitted with indwelling jugular vein catheters. On the following day (day 18), pigs were orally inoculated with 4.7x10^9 Salmonella Typhimurium. Blood samples were collected at 0.5-hour intervals from -2 to 8 hours, and at 8-hour intervals from 8 to 72 hours post-challenge. Whole blood was analyzed for complete blood cell counts using a ProCyte Dx Hematology Analyzer. Serum was isolated for measurement of cortisol. Following collection of the 72 hour sample, pigs were humanely euthanized and tissues were collected for Salmonella isolation. There was a sex by time interaction (P<0.001) for TEMP such that gilts had a greater TEMP response to the Salmonella challenge compared to barrows. There was also a sex by time interaction (P=0.03) for serum cortisol with gilts having decreased cortisol at 16 hours yet greater cortisol at 32 hours than barrows. Barrows had greater total white blood cells (17.8 vs. 16.2 +/- 0.4 10^3 cells/microliter; P<0.01; respectively) and neutrophils (7.8 vs. 6.1 +/- 0.4 10^3 cells/microliter; P<0.01; respectively) than gilts. However, gilts had greater lymphocytes (9.6 vs. 9.0 +/- 0.2 10^3 cells/microliter; P=0.05; respectively) than barrows. While immune parameters were influenced by sex, there were no effect of sex (P>0.05) on Salmonella concentrations from fecal shedding 4 days post-inoculation, in the cecum, mesenteric and subiliac lymph nodes, liver, spleen, gallbladder, or kidney tissues. These data demonstrate that weaned gilts produced a stronger immune response to a Salmonella challenge compared to barrows, without affecting the tissue translocation or shedding of Salmonella.