PSIII-7 - Evaluation of Maternal Selenium Supplementation and Plane of Nutrition During Gestation on the Neonatal Fc Receptor (FcRn) in Lamb Intestinal Tissue

Abstract: Maternal selenium (Se) supply and plane of nutrition alter morbidity and mortality in lambs as well as 24-h serum IgG. The neonatal Fc receptor (FcRn) transports IgG across mucosal surfaces; however, its role in intestinal protection in the lamb is unknown. Additionally, the effects of maternal nutrition on offspring FcRn abundance has not been reported. The objective of this study was to evaluate intestinal FcRn abundance in lambs born from ewes fed differing levels of nutrition and Se. Intestinal tissues from two experiments (EXP1 n=71; EXP2 n=80) were used. Both experiments utilized a 2x3 factorial design. Main effects included Se supplementation [adequate (9.5 or 11.5 μg/kg of BW in EXP1 or EXP2; respectively) or high, (81.1 or 77.0 μg/kg of BW in EXP1 or EXP2; respectively)] and plane of nutrition [60% (RES), 100% (CON), or 140% (HIGH) of requirements for both experiments]. Lambs were raised to 57 d or 21 d (EXP1 and EXP2; respectively). Intestinal tissues were collected and fixed in 10% NBF prior to paraffin embedding. Cross-sections were stained for FcRn and counterstained with DAPI. Areas of tissue cross-sections were captured with Plan-Apochromat 20x/0.8 NA lens using the tiling module of Zeiss. Images were analyzed using ImagePro Premiere software. Relative fluorescence within areas of interest was used as an indicator of FcRn receptor abundance. Data were analyzed using the general linear model procedure of SAS. Maternal nutrition tended (P≤0.07) to affect lamb intestinal FcRn abundance with CON having higher abundance compared to HIGH or RES (EXP1). There was no effect of maternal nutrition in EXP2 or maternal Se supplementation on intestinal FcRn abundance in lambs from either experiment (P≥0.56). These data show that maternal nutrition may influence offspring FcRn abundance and that further studies examining the contribution of lamb age are needed.