Biochemistry and Immune Biomarkers Indicate Interacting Effects of Pre- and Postnatal Stressors in Pigs across Sexes

Abstract

The effects of maternal immune activation (MIA) elicited by a prenatal stressor and postnatal metabolic or immune stressors on chemical and inflammatory biomarkers were studied in male and female pigs. Pigs exposed to MIA elicited by porcine reproductive and respiratory syndrome virus and matching controls were assigned at two months of age to fasting stress, immune stress, or a saline group. The serum levels of over 30 chemistry and immune analytes were studied. Significantly low levels of blood urea nitrogen were detected in females exposed to MIA, while the highest creatinine levels were identified in fasting females exposed to MIA. The levels of interferon gamma and interleukin 8 were highest in pigs exposed to postnatal immune challenge. The profiles suggest that MIA may sensitize pigs to postnatal stressors for some indicators while making them more tolerant of other stressors. Effectiveness of practices to ameliorate the impact of postnatal stressors on the physiology of the pig could be enhanced by considering the prenatal stress circumstances.

The Combined Effect of Weaning Stress and Immune Activation during Pig Gestation on Serum Cytokine and Analyte Concentrations

“…The females were moved on gestation day 69 to containment chambers that house one sow per crate. The gilts had unrestricted access to water and received a diet that supported gestation requirements totaling 2.3 kg/day [ 27 ]. Supplementary Table S1 lists the ingredients of the diets used in this study.…”

“…Blood collection was at 22 days of age, at 7:00 AM, and after the pigs were intramuscularly anesthetized with a telazol:ketamine:xylazine drug cocktail at a dose of 0.03 mL/kg body weight. The anesthesia cocktail included 50 mg of zolazepam (reconstituted with 2.5 mL ketamine, 100 g/L), 2.5 mL of xylazine (100 g/L) and 50 mg of tiletamine (Fort Dodge Animal Health, Fort Dodge, IA, USA), as per published protocols [ 17 , 27 ]. The ketamine:xylazine anesthetic combination does not affect the blood profiles of non-esterified fatty acids lactate, triglycerides, urea, cholesterol or glucagon in the timespan of the experiments [ 33 ].…”

“…The combined effect of MIA elicited by PRRSV infection and a lipopolysaccharides (LPS) immune challenge of 28-day-old pigs altered the blood levels of IL-1β and IL-10 differently than the accumulation of the individual MIA or LPS challenge effects [ 15 ]. Our studies also identified significant effects of the interaction between PRRSV-elicited MIA and immunological and metabolic stressors in the serum levels of cytokines and chemistry and locomotion behavior of 60-day-old pigs [ 26 , 27 ].…”

“…Persistent behavior and physiological disruptions have been associated with prenatal exposure to inflammation signals in mice and pigs [ 25 , 26 , 27 ]. For example, immune activation during gestation triggered by the viral mimetic polyinosinic-polycytidylic acid (Poly(I:C)) was associated with significant changes in the levels of cytokine genes in the blood of 7-day-old mice [ 28 ].…”

“…Most reports about the two-hit hypothesis have explored the effects of MIA followed by a postnatal challenge such as LPS or Poly(I:C) that is expected to elicit substantial physiological or immunological responses [ 30 , 31 , 32 ]. We detected significant effects of MIA and a postnatal Poly(I:C) immune challenge in the behavior and blood profiles of 60-day-old pig [ 26 , 27 ]. We propose that the two-hit model is also applicable to the interaction between MIA and less acute postnatal challenges such as weaning.…”