Location: Livestock Issues Research
Project Number: 3096-32000-008-09-T
Project Type: Trust Fund Cooperative Agreement
Start Date: Apr 1, 2015
End Date: Mar 31, 2020
The objective of this experiment is to determine if feeding XPC or SynGenX to weaned pigs will reduce the stress and pro-inflammatory responses following an oral Salmonella Typhimurium challenge, and whether or not bacteria shedding and in vivo bacteria translocation profiles are altered.
Forty weaned gilts (approximately 19 to 21 days of age) will be obtained from a commercial swine farm, individually ear tagged, and transported to the Livestock Issues Research Unit’s environmentally-controlled nursery facility in Lubbock, TX. Pigs will be individually housed in stainless steel pens equipped with nipple waterers and stainless steel feeders allowing ad libitum feed and water intake. Pigs will be weighed on the day of arrival, blocked by body weight, and assigned to one of four treatment groups (n = 10 pigs/treatment group): 1) Control – fed a non-medicated starter diet; 2) XPC – fed the control diet supplemented with Original XPC at 4 lb/ton; 3) SGX1 – fed the control diet supplemented with SynGenX at 2 lb/ton; and 4) SGX2 – fed the control diet supplemented with SynGenX at 4 lb/ton (Table 2). All pigs will remain on their respective diets for 18 days. Pigs and feeders will be weighed weekly. On day 7, pigs will be anesthetized and a small incision will be made in the lower abdominal region that will allow for the placing of an indwelling temperature recording device into the peritoneal cavity which will be retrieved upon the termination of the study. Intra-peritoneal temperature will be measured at 5-min intervals from -7 to +1 days relative to the LPS challenge. On day 14, pigs will be anesthetized and jugular cannulas will be inserted using a nonsurgical method. On the following day (day 15), all pigs will be challenged through the jugular cannula with an E. coli-derived lipopolysaccharide (LPS; 25 ug/kg body weight). From each pig, a total of 22 blood samples will be collected from the jugular cannula at 0.5-hour intervals from -2 to 8 hours and at 24 hours relative to the LPS challenge from all pigs for serum isolation. Serum isolated from blood samples will be stored at -80oC until analyzed for cortisol using commercially available kit according to the manufacturer’s instructions that has been previously validated in our lab, and three pro-inflammatory cytokines (i.e., TNF-a, IL-1ß and IFN-') using a custom porcine 3-plex sandwich-based ELISA kit. Additionally, 12 whole blood samples (collected in a 4-mL vacutainer tube containing EDTA at each specified time point) will be collected from each pig from the jugular cannula at 1.0-hour intervals from -2 to 8 hours and at 24 hours to determine complete blood cell counts using a ProCyte Dx Hematology Analyzer. On days 7 (pigs and feeders), 11 (feeders), 14 (pigs and feeders; day prior to LPS challenge), 17 (feeders) and 18 (pigs and feeders) feeders and pigs will be weighed and date recorded to determine average daily feed intake, average daily gain, and feed conversion. Seventy-two hours after the LPS challenge (day 18), all feeders and pigs will be weighed, and then pigs will be euthanized for the retrieval of the temperature recording devices.