PSX-B-30 - Study of the effects of gestational and weaning stresses on blood cytokines and analytes in pigs

The effects of the practice of weaning in pigs have been documented, and include changes in organ function and immune mechanisms. However, the effects of weaning following exposure to maternal infection during gestation are incompletely characterized. We hypothesize that the disruption of physiological processes triggered by weaning can be influenced by the exposure of the pig to maternal immune signals elicited by a challenge during gestation. To test our hypothesis, the concentrations of biochemical indicators and cytokines were measured in the blood from 72 female and male pigs distributed across two weaning groups (nursed or weaned), and two gestational challenge groups (gilts infected with porcine reproductive and respiratory virus or healthy controls). Weaning had a significant effect on the concentration of albumin among females born from healthy gilts (P < 0.01). The albumin concentrations were higher in weaned relative to nursed pigs from healthy gilts. This pattern may be associated with the transition to a higher protein diet, whereas no differences were observed among pigs from infected gilts. The interaction between gestation and weaning stresses had a significant effect on the concentration of bicarbonate. The highest levels of bicarbonate were detected among nursed pigs from infected gilts. The lowest levels of bicarbonate were detected among weaned pigs from health gilts, and this could indicate metabolic acidosis. An interaction effect (P < 0.02) was detected for pro-inflammatory interleukin 4. The highest concentrations of interleukin 4 were detected in weaned females from infected gilts, while the lowest levels were detected among weaned males from health gilts. The studied biomarker patterns indicate that the effect of weaning on blood indicators can be influenced by the exposure of the pigs to challenges during gestation. This study is supported by USDA NIFA AFRI, grant number 2018-67015-27413.