Assessing the ability to immunomodulate the innate immune system and oxidative defense system of weaned pigs through prenatal lipopolysaccharide challenge in late gestating sows

Authors: MITCHELL, TY - Texas Tech University; Sanchez, Nicole; Carroll, Jeffery - Jeff Carroll; Broadway, Paul; LEGAKO, JERRAD - Texas Tech University; PETRY, AMY - Texas Tech University

Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 12/5/2022
Publication Date: 11/1/2023
Citation: Mitchell, T.M., Sanchez, N.C., Carroll, J.A., Broadway, P.R., Legako, J.F., Petry, A.L. 2023. Assessing the ability to immunomodulate the innate immune system and oxidative defense system of weaned pigs through prenatal lipopolysaccharide challenge in late gestating sows. Journal of Animal Science Supplement.

Interpretive Summary:

Technical Abstract: Gastrointestinal immunity and antioxidant defenses may be bolstered in young animals through prenatal immune system stimulation (PIS), but this is largely uninvestigated in the pig. The experimental objective was to determine if a low-dose of lipopolysaccharide (LPS) administered in late gestating sows would alter the immune response and oxidative status of her weaned pigs. On d 78±1.8 of gestation, fourteen Camborough sows (parity = 2.6±1.4) of the same farrowing group were blocked by weight, and randomly assigned to one of two treatments: intramuscular-injection of 5-ml of saline (CON) or LPS from E. coli O111:B4 (2.5 µg/kg of BW). Sow rectal temperatures and sickness behavior scores were recorded every 0.5 h from -0.5 h to 8 h and every 8 h from 8 to 48 h post-treatment administration. A subset of 34 weaned barrows (weaning age 21±1.3 d) from the experimental sow group (n=17 CON, LPS) were transported on d -7 to an environmentally controlled facility where they were individually housed. Pigs had ad libitum access to water and feed. On d -1, pigs were anesthetized for placement of a subcutaneous temperature logger and a jugular catheter. On d 0, all pigs were challenged i.v. with the same LPS strain (10 µg/kg BW). Body temperature was measured at 5-min intervals from the time of logger placement. Blood samples were collected at -2, 0, 1, 2, 4, 6, 8, 12, and 24 h relative to LPS administration at 0 h. After the 24 h blood draws were collected, pigs were necropsied for ileal and jejunal tissue. Plasma samples and jejunal and ileal tissues were analyzed for total antioxidant capacity (TAC) and malondialdehyde (MDA). Data were analyzed as a linear mixed model using PROC MIXED (SAS 9.4) with treatment and time as fixed effects. A dependent covariance structure was used for repeated measurements. Sows administered LPS had elevated rectal temperatures from 2 to 16-h post-challenge with a return to baseline by h 24 indicating mild immune stimulation (treatment × time P<0.001). Similarly, sows exposed to LPS had increased sickness behavior scores from 2 to 3.5-h post-challenge (treatment × time P<0.001). Pigs exposed to PIS had greater subcutaneous body temperature than CON at 1 and 2-h post-LPS challenge (treatment × time P<0.001). An increase in plasma TAC at 2 and 4-h post LPS challenge was observed in pigs exposed to PIS relative to CON (treatment × time P =0.004). Irrespective of treatment, LPS increased plasma MDA from 2 to 24-h post-challenge (Time P<0.001). There was no effect of PIS on ileal or jejunal tissue TAC (P>0.4), but weaned pigs exposed to PIS has decreased jejunal MDA (P=0.049). Collectively, it appears PIS may alter the innate immune response and oxidative status of the weaned pig during a LPS challenge.