57 Trainee Award: Nutrient restriction during gestation influences fetal small intestine weight, histomorphology, and microbial diversity

Abstract Abstract: Introduction Proper development of the small intestinal epithelium and establishment of a diverse microbiome is critical for transport and absorption of nutrients, and gut health, but may be negatively impacted by restricted nutrition during gestation. Objective To determine if maternal nutrient restriction impairs morphological characteristics and microbial community of fetal small intestine, multiparous Dorset ewes pregnant with twins were fed 100% (n = 8) or 60% (n = 7) of requirements from d 30 – d 130 of gestation. Ewes were euthanized at d 130 of gestation, and fetal measurements and samples were collected. Fetuses are referred to as CON (n = 8 female; n = 8 male) or RES (n = 9 female; n = 5 male), corresponding to their dam’s diet. DNA was extracted from jejunal mucosal scrapings and v4 of 16S was amplified and sequenced to determine microbial diversity. Results Small intestine weight (g/kg BW) in RES-females was 11.5% lighter than CON-females (P=0.04). In the duodenum, villi height (VH; µm) were 20.2% and 21.6% shorter in RES-males relative to CON-males and RES-females (P≤0.04). In the jejunum, VH were 7.9% and 10.6% shorter in RES-males relative to CON-females and RES-females (P≤0.03). In the ileum, VH were 11.5% shorter in CON-males relative to CON-females (P=0.005). A Shannon Index for α-diversity revealed that RES-males have decreased diversity relative to CON-females (P=0.013) and a Bray-Curtis analysis for β-diversity had a main effect of treatment (P=0.04) indicating a difference in species composition. Conclusion Maternal nutrient restriction during gestation influences fetal offspring small intestine development and microbial environment in a sex-specific manner. (Supported by USDA-NIFA 2023-67012-39740)