Fetal Development Research Articles

The Prevalence and Awareness of Congenital External Ear Deformity among the School-Age Group: A Cross-Sectional Study.

Congenital outer ear deformities stem from a sequence of disturbances during fetal auricular cartilage embryonic development. A significant gap exists in understanding their prevalence among the school-age group in Saudi Arabia. This cross-sectional study aims to address this knowledge gap to raise awareness about the impact of such disorders. This cross-sectional study targeted parents of children in the school-age group. A multistage cluster sampling technique was employed to ensure the representation of schools. A self-administered Google form survey was used. Data were analyzed using IBM SPSS Statistics for Windows, Version 28.0 (IBM Corp., Armonk, NY). Our study revealed that the majority were males (56.2%), aged 6 to 10 years (49.3%), and attended primary school (69.5%). Chronic illnesses were present in 7.1% of children, with hearing impairment most prevalent (25.9%). Congenital ear deformities affected 2.7% of children, primarily Stahl's ear (35.4%). Limited knowledge about these deformities was observed among respondents (30.3%), yet a significant majority (73.9%) expressed belief in the potential of community awareness to decrease deformity prevalence. The awareness levels were impacted by parental education but showed no significant association with the child's age, gender, or presence of chronic diseases. Our study underscores the noteworthy occurrence of congenital ear deformities among the school-age group, coupled with a notable lack of awareness. Parental education emerges as a key factor influencing awareness levels. It is imperative to prioritize initiatives to bolster awareness and early detection to promote child health.

Epigenetic Pathways Linking Fetal Development to Metabolic Syndrome: Mechanisms and Implications

This review explores the intricate connections between early developmental environments, epigenetic mechanisms, and long-term health outcomes. The concept of fetal programming highlights how maternal stress, nutrition, and other environmental factors during embryonic and fetal development can induce physiological changes with persistent effects extending into adulthood and across generations. Evidence suggests that these early life exposures can lead to complex diseases such as cardiovascular conditions, diabetes, and metabolic syndrome. The role of epigenetic modifications—particularly DNA methylation and histone modifications—is emphasized as a crucial mechanism through which environmental factors influence gene expression and disease susceptibility. Additionally, this review discusses the significance of sex-specific epigenetic marks and their impact on disease risk, illustrating how sex chromosomes and fluctuating sex hormones contribute to sexual dimorphism in disease prevalence. The need for further research is underscored, with a focus on understanding the factors that shape fetal growth trajectories, the mechanisms by which nutrients and hormones alter gene expression, and the barriers to healthy eating among women. Addressing these issues is vital for reducing chronic disease prevalence and improving public health across generations.

Placental growth factor alleviates hyperglycemia-induced trophoblast pyroptosis by regulating mitophagy.

Hyperglycemia is closely related to trophoblast dysfunction during pregnancy and results in suppressed invasion, migration, and pro-inflammatory cell death of trophoblasts. Hyperglycemia is a dependent risk factor for gestational hypertension accompanied by decreased placental growth factor (PLGF), which is important for maternal and fetal development. However, there is currently a lack of evidence to support whether PLGF can alleviate trophoblast cell dysfunction caused by high blood sugar. Here, we aim to clarify the effect of hyperglycemia on trophoblast dysfunction and determine how PLGF affects this process. The changes in placental tissue histomorphology from gestational diabetes mellitus (GDM) patients were compared with those of normal placentas. HTR8/SVneo cells were cultured in different amounts of glucose to examine cellular pyroptosis, migration, and invasion as well as PLGF levels. Furthermore, the levels of pyroptosis-related proteins (NLRP3, pro-caspase1, caspase1, IL-1β, and Gasdermin D [GSDMD]) as well as autophagy-related proteins (LC3-II, Beclin1, and p62) were examined by Western blotting. The GFP-mRFP-LC3-II system and transmission electron microscopy were used to detect mitophagy levels, and small interfering RNAs targeting BCL2 Interacting Protein 3 (siBNIP3) and PTEN-induced kinase 1 (siPINK1) were used to determine the role of mitophagy in pyroptotic death of HTR-8/SVneo cells. Our results show that hyperglycemia upregulates NLRP3, pro-caspase1, caspase1, IL-1β at the protein level in GDM patients. High glucose (HG, 25 mM) inhibits viability, invasion, and migration of trophoblast cells while suppressing superoxide dismutase levels and promoting malondialdehyde production, thus leading to a senescence associated beta-gal-positive cell burst. PLGF levels in nucleus and the cytosol are also inhibited by HG, whereas PLGF treatment inhibited pyroptosis-related protein levels of NLRP3, pro-caspase1, caspase1, IL-1β, and GSDMD, Gasdermin D N-terminal domain (GSDMD-N). HG-induced mitochondrial dysfunction and BNIP3 and PINK1/Parkin expression. Knocking down BINP3 and PINK1 abolished the protective role of PLGF by preventing mitophagy. PLGF inhibited hyperglycemia, while PLGF reversed hyperglycemic injury by promoting mitophagy via the BNIP3/PINK1/Parkin pathway. Altogether, these results suggest that PLGF may protect against trophoblast dysfunction in diabetes.

Predicting newborn birth outcomes with prenatal maternal health features and correlates in the United States: a machine learning approach using archival data

BackgroundNewborns are shaped by prenatal maternal experiences. These include a pregnant person’s physical health, prior pregnancy experiences, emotion regulation, and socially determined health markers. We used a series of machine learning models to predict markers of fetal growth and development—specifically, newborn birthweight and head circumference (HC).MethodsWe used a pre-registered archival data analytic approach. These data consisted of maternal and newborn characteristics of 594 maternal-infant dyads in the western U.S. Participants also completed a measure of emotion dysregulation. In total, there were 22 predictors of newborn HC and birthweight. We used regularized regression for predictor selection and linear prediction, followed by nonlinear models if linear models were overfit.ResultsHC was predicted best with a linear model (ridge regression). Newborn sex (male), number of living children, and maternal BMI predicted a larger HC, whereas maternal preeclampsia, number of prior preterm births, and race/ethnicity (Latina) predicted a smaller HC. Birthweight was predicted best with a nonlinear model (support vector machine). Occupational prestige (a marker similar to socioeconomic status) predicted higher birthweight, maternal race/ethnicity (non-White and non-Latina) predicted lower birthweight, and the number of living children, prior preterm births, and difficulty with emotional clarity had nonlinear effects.ConclusionsHC and birthweight were predicted by a variety of variables associated with prenatal stressful experiences, spanning medical, psychological, and social markers of health and stress. These findings may highlight the importance of viewing prenatal maternal health across multiple dimensions. Findings also suggest that assessing difficulties with emotional clarity during standard obstetric care (in the U.S.) may help identify risk for adverse newborn outcomes.

Anatomical description of a pygmy sperm whale, Kogia breviceps (Cetacea: Kogiidae), pre-term calf using CT scan and 3D reconstructions.

Little is known about the biology of pygmy sperm whales, Kogia breviceps (De Blainville, 1838), being that most anatomical descriptions for the species derive from necropsy after stranding or from osteological material preserved in museums. This species is rarely seen despite its wide distribution, and its reproductive behaviour is still being investigated. The eventual occurrence of pregnant female strandings and the collection and description of foetuses can give clues about the organisms' mostly unknown early development. However, this type of biological material is extremely rare, limiting anatomical analysis due to the risk of damage or loss. Here, we describe the external and internal anatomy of an 84 cm long K. breviceps foetus. The methods utilised were non-intrusive, meaning that no incisions were made on the specimen. The foetus was analysed using computed tomography images and a three-dimensional reconstruction of the skeleton. A great number of features were observed, such as axial and appendicular skeletal structures, internal organs, echolocation apparatus and umbilical cord, as well as diagnostic characters of the species, such as the asymmetrical skull, spermaceti chamber and false gill pigmentation. We suggest that more specimens on different stages of development should be analysed by the same technique, as well as further comparison with specimens from other taxa, in order to facilitate more comparative studies on embryonic and foetal development of cetaceans.

Prenatal glucocorticoids exposure and adverse cardiovascular effects in offspring.

Glucocorticoids (GCs) are steroid hormones fundamental to the body's normal physiological functions and are pivotal in fetal growth and development. During gestation, the mother's cortisol concentration (active GCs) escalates to accommodate the requirements of fetal organ development and maturation. A natural placental GCs barrier, primarily facilitated by 11β hydroxysteroid dehydrogenase 2, exists between the mother and fetus. This enzyme transforms biologically active cortisol into biologically inactive corticosterone, thereby mitigating fetal GCs exposure. However, during pregnancy, the mother may be vulnerable to adverse factor exposures such as stress, hypoxia, caffeine, and synthetic GCs use. In these instances, maternal serum GCs levels may surge beyond the protective capacity of the placental GCs barrier. Moreover, these adverse factors could directly compromise the placental GCs barrier, resulting in excessive fetal exposure to GCs. It is well-documented that prenatal GCs exposure can detrimentally impact the offspring's cardiovascular system, particularly in relation to blood pressure, vascular function, and heart function. In this review, we succinctly delineate the alterations in GCs levels during pregnancy and the potential mechanisms driving these changes, and also analyze the possible causes of prenatal GCs exposure. Furthermore, we summarize the current advancements in understanding the adverse effects and mechanisms of prenatal GCs exposure on the offspring's cardiovascular system.

Paternal undernutrition and overnutrition modify semen composition and preimplantation embryo developmental kinetics in mice

BackgroundThe importance of parental diet in relation to eventual offspring health is increasing in prominence due to the increased frequency of parents of reproductive age consuming poor diets. Whilst maternal health and offspring outcome have been studied in some detail, the paternal impacts are not as well understood. A father’s poor nutritional status has been shown to have negative consequences on foetal growth and development and ultimately impact the long-term adult health of the offspring. In this study, we examined sperm- and seminal vesicle fluid-mediated mechanisms of preimplantation embryo development alterations in response to sub-optimal paternal diets.ResultsMale mice were fed a diet to model either under (low-protein diet (LPD)) or over (high-fat/sugar ‘Western’ diet (WD)) nutrition, LPD or WD supplemented with methyl donors or a control diet (CD) before mating with age-matched females. Male metabolic health was influenced by WD and MD-WD, with significant changes in multiple serum lipid classes and hepatic 1-carbon metabolites. Sperm RNA sequencing revealed significant changes to mRNA profiles in all groups when compared to CD (LPD: 32, MD-LPD: 17, WD: 53, MD-WD: 35 transcripts). Separate analysis of the seminal vesicle fluid proteome revealed a significant number of differentially expressed proteins in all groups (LPD: 13, MD-LPD: 27, WD: 24, MD-WD: 19) when compared to control. Following mating, in vitro time-lapse imaging of preimplantation embryos revealed a significant increase in the timing of development in all experimental groups when compared to CD embryos. Finally, qPCR analysis of uterine tissue at the time of implantation identified perturbed expression of Cd14 and Ptgs1 following mating with WD-fed males.ConclusionsOur current study shows that paternal nutritional status has the potential to influence male metabolic and reproductive health, impacting on embryonic development and the maternal reproductive tract. This study highlights potential direct (sperm-mediated) and indirect (seminal vesicle fluid-mediated) pathways in which a father’s poor diet could shape the long-term health of his offspring.

Mapping the anatomical and transcriptional landscape of early human fetal ovary development

Mapping the anatomical and transcriptional landscape of early human fetal ovary development

Iodine nutrition among pregnant women in the Faroe Islands.

Ensuring adequate iodine nutrition during pregnancy is crucial for fetal brain development. Thus, the WHO recommend monitoring iodine nutrition in pregnant women. With changing dietary habits and declining iodine intake in coastal populations, iodine nutrition in pregnant Faroese women was a focus in newly established pregnancy cohorts. This study aimed to monitor the iodine status of pregnant women in the Faroe Islands by assessing urinary iodine concentration (UIC) and maternal iodine intake. For 2 years, all pregnant women were invited to participate in a nationwide study. Participants completed questionnaires addressing personal and lifestyle factors, supplement intake and dietary habits, Additionally, they provided spot urine samples for UIC measurements. Iodine was measured spectrophotometrically using the ceri/arsen method after alkaline-ashing. Among the 1030 invited, 654 participated and 647 provided a spot-urine sample. The average age was 30·4 years (18–47 years). The overall median UIC was 110 µg/l, declined from 117 to 101 µg/l over 2 years (P = 0·004). UIC was significantly impacted by diet. Women consuming fish and eggs had a higher median UIC compared with those whose primary iodine source was dairy: fish-dinner, 151 µg/l; dairy products, 112 µg/l (P < 0·001). Furthermore, there was a positive association between maternal age, reported intake of iodine-containing supplements and the UIC. This nationwide study of pregnant Faroese women found UIC below the WHO-recommended cut-off for pregnant women and decreasing with time. This decline highlights the importance of continuous monitoring to prompty identify shifts in iodine status, enabling timely intervention to address emerging deficiencies.

Technical considerations for placental tissue processing and the subsequent impact on genome-wide DNA methylation analysis

To assess the impact of postnatal processing on placental DNA methylation, array data from flash-frozen placental tissue was compared to perfluorocarbon-immersed and formalin-fixed paraffin-embedded placental tissue. We observed that tissue exposed to perfluorocarbon showed no significant DNA methylation differences when compared to unprocessed tissue, while formalin processing altered the quality and reliability of the data produced on the DNA methylation array platform. Placental DNA methylation allows for the study of gene–environment interactions that influence the fetal environment and development. Our study highlights that placental post-processing techniques must be considered in the evaluation and interpretation of epigenetic studies.

A multichannel microfluidic device for revealing the neurotoxic effects of Bisphenol S on cerebral organoids under low-dose constant exposure

Bisphenol S is a widely used plasticizer in manufacturing daily supplies, while little was known about its adverse effect on human health, especially on fetal brain development. Due to the complexity and subtlety of the brain, it remains challenging to reveal the hazardous effects of environmental pollution on human fetal brain development. Taking advantage of stem cell application, cerebral organoids generated from stem cells are becoming powerful tools for understanding brain development and drug toxicity testing models. Here, we developed a microfluidic chip for cerebral organoid culturing to reveal the neurotoxicity of low-dose constant BPS exposure on cerebral organoids. The organoids in our microfluidic system could be continuously cultured for 34 days and expressed all the essential properties of the cerebral organoids. Exposure to BPS was initiated from day 20 for concessive two weeks. The neurotoxic effects were evaluated by immunofluorescence staining and proteomics, and verified by quantitative real-time PCR. Our results indicated BPS exposure would inhibit neuron differentiation, hinder the Wnt signaling pathway, and cause alteration of signaling molecule expressions in brain regionalization. Even exposure to a low dose of BPS constantly might cause neurotoxicity during fetal brain development. Altogether, the multichannel microfluidic chip offers a general platform technique to reveal the effects of different hazardous chemicals on cerebral organoids.

PSI-6 Early life programming of the bovine jejunum function in response to maternal vitamin and mineral supplementation

Abstract Despite the increased appreciation of the involvement of maternal nutrition in fetal development, its effects on jejunum programming remain largely unexplored. Here, we investigated the impact of maternal vitamin and mineral supplementation throughout gestation on the differential gene expression and underlying biological pathways in the jejunum of neonatal calves. For this, beginning 60 d before breeding and continuing throughout gestation, crossbred Angus heifers (n = 14) were fed either a basal diet (CON; n = 7) or the basal diet plus 113 g•heifer-1•d-1 of VTM supplement (VTM; n = 7). All heifers were gestating female calves, which were euthanized 30 h after birth. Samples of jejunum mucosa were collected, stored at -80°C, then subjected to total RNA isolation and RNA sequencing. After quality control, the reads were mapped using STAR aligner and differentially expressed genes (DEGs) were identified using DESeq2. Maternal VTM supplementation did not affect calf organ mass, including jejunum weight. However, high-resolution respirometry analysis revealed greater mitochondrial efficiency in jejunum of calves from VTM supplemented dams. Additionally, we identified 528 DEGs between the VTM and CON calves (P-value ≤ 0.05 and |log2FC| &amp;gt; 0.5). Among them, the genes IGFBP2 and IGFBP6, which are key genes in insulin pathway and involved in regulation of insulin-like growth factors (IGF), IGF transport, and uptake, were upregulated in the VTM group. Additional pathways were identified using ShinyGO, which included the pancreatic secretion pathway, over-represented by genes such as PLCB1, CCK, and SLC26A3. The gene PLCB1 has been associated with feed efficiency, growth, and carcass traits in multiple species. Likewise, the SLC26A3 gene encodes a key intestinal chloride anion exchanger associated with enhanced feed efficiency in cattle. Genes encoding signaling molecules involved with immune response, T cell activation, and defense response were also among the DEGs upregulated in the VTM calves, including the TNFSF18 and TNFRSF4 genes. Our findings suggest that maternal prenatal vitamin and mineral supplementation throughout gestation affects the expression of genes involved in the jejunum function of offspring at a neonatal time point. The long-term consequences of these changes, however, warrant further investigation.

Development and child health in a world of synthetic chemicals.

Chemical pollution is one of today's most significant threats to the developmental potential of children worldwide. Maternal exposure to toxicants can perturb sensitive windows of fetal development, indirectly through promoting antenatal disorders, abnormal placental adaptation, or directly through maternal-fetal transport. Current evidence clearly shows that persistent organic chemicals promote hypertensive disorders of pregnancy, placental abnormalities, and fetal growth restriction, whereas findings are less consistent for phthalates and bisphenols. Prospective birth cohorts strongly support a link between adverse neurodevelopmental outcomes and prenatal exposure to flame retardants and organophosphate pesticides. Emerging evidence reveals a potential association between in utero exposure to bisphenols and childhood behavioral disorders, while childhood metabolic health is more consistently associated with postnatal exposure to phthalates and bisphenols. IMPACT: Synthesizes emerging evidence linking modern forms of chemical pollution to antenatal disorders, fetal growth restriction and childhood disorders. Highlights potential developmental impacts of emerging pollutants of concern now ubiquitous in our environment but without regulatory restrictions.

Prediction of fetal brain gestational age using multihead attention with Xception

Accurate gestational age (GA) prediction is crucial for monitoring fetal development and ensuring optimal prenatal care. Traditional methods often face challenges in terms of precision and prediction efficiency. In this context, leveraging modern deep learning (DL) techniques is a promising solution. This paper introduces a novel DL approach for GA prediction using fetal brain images obtained via magnetic resonance imaging (MRI), which combines the strength of the Xception pretrained model with a multihead attention (MHA) mechanism. The proposed model was trained on a diverse dataset comprising 52,900 fetal brain images from 741 patients. The images encompass a GA ranging from 19 to 39 weeks. These pretrained models served as feature extraction components during the training process. The extracted features were subsequently used as the inputs of different configurable MHAs, which produced GA predictions in days. The proposed model achieved promising results with 8 attention heads, 32 dimensionality of the key space and 32 dimensionality of the value space, with an R-squared (R2) value of 96.5 %, a mean absolute error (MAE) of 3.80 days, and a Pearson correlation coefficient (PCC) of 98.50 % for the test set. Additionally, the 5-fold cross-validation results reinforce the model's reliability, with an average R2 of 95.94 %, an MAE of 3.61 days, and a PCC of 98.02 %. The proposed model excels in different anatomical views, notably the axial and sagittal views. A comparative analysis of multiple planes and a single plane highlights the effectiveness of the proposed model against other state-of-the-art (SOTA) models reported in the literature. The proposed model could help clinicians accurately predict GA.

438 DNA methylation patterns and transcriptional regulation during pig fetal skeletal muscle development

Abstract Fetal development is controlled by a complex cascade of highly regulated and coordinated gene expression patterns. Epigenetic mechanisms have important roles in regulating development and differentiation. Among such mechanisms, DNA methylation exhibits context-specific associations with gene expression and has been shown to be highly dynamic during developmental processes. We performed whole-genome bisulfite sequencing (WGBS) to assess DNA methylation in pig longissimus dorsi muscle at 41- and 70-d gestation (dg), as well as RNA- and small RNA-sequencing to identify coordinated changes in methylation and expression between myogenic stages. We identified 45,739 differentially methylated regions (DMRs) between stages, and the majority (n = 34,232) were hypomethylated at 70 vs. 41 dg. Developmental DMRs exhibited feature-specific enrichment in gene regulatory regions, as well as in regions proximal to micro-RNAs (miRNAs) that have known roles in myogenesis. Integration of methylation and transcriptomic data revealed strong associations between differential gene methylation and transcript abundance. We surveyed myogenic regulatory factor (MRF) genes to determine if differential methylation was present in expected genomic regions. Within the MYF5 and MYF6 locus, MYF5 was significantly promoter-hypermethylated at 70 dg, whereas MYF6 was significantly hypomethylated upstream of its transcription start site. MYF5 is the earliest MRF to be expressed and primarily functions in myoblast proliferation and determination, while MYF6 functions in muscle cell differentiation. Thus, these patterns were consistent with expected downregulation of MYF5 and upregulation of MYF6 as muscle development progresses and demonstrate that differential methylation is evident at myogenic transcription factors. Differential miRNA methylation was significantly negatively correlated with abundance, and dynamic expression of assayed miRNAs persisted postnatally. Motif analysis revealed significant enrichment of myogenic regulatory factor motifs among hypomethylated regions, suggesting that DNA hypomethylation may function to increase accessibility of muscle-specific transcription factors. We also show that developmental DMRs are enriched for GWAS SNPs associated with muscle physiology and meat quality traits, demonstrating the potential for epigenetic processes to influence phenotypic diversity. Our results enhance understanding of DNA methylation dynamics in pig fetal skeletal muscle and reveal putative cis-regulatory elements governed by epigenetic processes during porcine myogenesis.

270 Prenatal stress programming: Impact on dam and offspring immune phenotype and performance

Abstract Maternal stress during critical periods of fetal development is linked to the modified expression of several physiological processes. Despite attempts to minimize chronic stress and enhance sow well-being, some animals still experience stress, which can have short and long-term effects on future progeny. Therefore, we evaluated the impact of maternal stress on the immune phenotype and performance of pregnant gilts who had experienced pre- and post-natal stress and whether their offspring were affected. A total of 11 primiparous females (201.32 ± 17.18 kg at farrowing) clustered into treatment groups based on the treatment of their dams were used in this study. Their dams had been randomly allotted to receive either a placebo (CON) or Hydrocortisone Acetate capsules twice per day for 21 d during either mid (MID; d 51 to 72) or late (LATE; d 81 to 102) gestation. Prenatally stressed dams were sampled on gestational d 45, 60, 75, and 105 to determine descriptive and functional immune analysis. Productivity measures were assessed, including farrowing duration and the interval between piglets. Blood samples were taken from a subset of piglets born to these dams on d 7, 14, and 21 of lactation and then 24 h, 7, and 14 d post-wean. Data were analyzed using the Mixed procedure of SAS with repeated measures. Numbers of lymphocytes were elevated in gilts from LATE-treated dams compared with those from MID or CON dams for the entire study period (P &amp;lt; 0.05). All other descriptive immune measures, including neutrophil-to-lymphocyte ratio, were not different between groups during the gestational period. Mitogen-induced lymphocyte proliferation did not differ across treatments for prenatally stressed dams. No maternal treatment effects for any litter traits, farrowing duration, or interval between each piglet, but there was a tendency (P &amp;lt; 0.10) for piglets born to MID-stressed dams to be heavier than those born to CON dams. Total lymphocyte numbers were least in the progeny of MID-treated dams compared with piglets from LATE and CON dams for the entire lactation period. Over time, progeny from LATE-treated gilts had a more stimulated B-cell proliferation index during lactation (P &amp;lt; 0.05). Conversely, Concanavalin-A-induced lymphocyte proliferation tended to be least in offspring from MID-treated dams compared with CON. They also tended to have less percentage and numbers of lymphocytes than offspring from LATE and CON dams for the entire post-wean period. The offspring from MID-treated dams also had the greatest (P &amp;lt; 0.05) neutrophil-to-lymphocyte ratio for the entire period. While prenatal stress had minimal impact on the immune expression of the dam, its influence was evident in their progeny, particularly with MID. Results indicate that the programming effects may only be apparent in later generations. The study also suggests that mid-gestation is a more sensitive period for maternal stress in fetal development.

429 Maternal rate of gain and one-carbon metabolites supplementation alters the gene expression profile of fetal brain during early gestation in beef heifers

Abstract Maternal nutritional plane during pregnancy may leave lifelong impacts on offspring in beef cattle. Given that, we hypothesized that the supplementation of one-carbon metabolites (OCM) during pregnancy would mitigate the negative effects of maternal rate of gain through brain gene expression regulation in early developing bovine fetuses. The objective of this study was to evaluate the effects of OCM supplementation and maternal rate of gain on gene expression in the developing fetal brain in gestating beef heifers. Herein, Angus crossbred heifers (n = 72, body weight = 406 ± 33 kg) were randomly assigned to 2 × 2 factorial arrangement of treatments with two levels of maternal rate of gain (CON, 0.60 kg/d; and RES, -0.23 kg/d) each with or without OCM supplementation (+OCM, and -OCM). Heifers were fed individually and were bred using female-sexed semen from a single sire. The OCM supplementation included rumen-protected choline (44.4 g/d) and methionine (7.4 g/d) in corn carrier fed daily and weekly injections of folate (320 mg) and vitamin B12 (20 mg). The -OCM heifers received the corn carrier and saline injections. The treatments started at the time of breeding and continued until d 63 of gestation when pregnant heifers (n = 29) were slaughtered to collect fetal brain tissues for RNA sequencing. The fetal brain phenotypic data were analyzed using MIXED procedures of SAS, indicating that restricted nutrition affected the fetal right hemisphere weight (P &amp;lt; 0.05), and there was a strong tendency for overall fetal brain weight (0.05 &amp;lt; P &amp;lt; 0.1) to be affected as well. Brain transcriptomics data were analyzed using STAR aligner and a total of 177 differentially expressed genes (DEGs, FDR &amp;lt; 0.05) were identified across all treatment comparisons using DESeq2. Most of the DEGs were either isoforms of spliceosomal non-coding RNAs or micro-RNAs (miRNAs) associated with biological processes (FDR &amp;lt; 0.1) like mRNA processing, cellular nitrogen metabolism, lipid metabolism, and post-transcriptional gene silencing. The key miRNAs upregulated in the brain tissue of restricted fetuses without OCM supplementation, bta-mir-2375, bta-mir-876, and bta-mir-196a-1, were found to be associated with early embryogenesis and essential cellular regulatory processes. Conversely, in restricted fetuses with OCM supplementation, upregulated miRNAs such as bta-mir-216b, bta-mir-2285dd, and bta-mir-1298 were linked to early embryonic development, muscular development, and lipid metabolism in cattle. Both phenotypic and transcriptomics data here revealed that the maternal rate of gain altered fetal brain development, with differences seemingly compensated by OCM supplementation. USDA is an equal opportunity provider and employer.

436 Regulation of brain-placental axis in mouse versus pig

Abstract Emerging evidence suggests that the placenta has key roles in the development of mammalian brain. The brain-placental axis refers to the molecular and cellular events by which the placenta programs the fetal brain development during reproduction and leaves a lasting influence on the health and disease of the brain later in life. Though most studies on the brain-placental axis have utilized mouse models, the pig, Sus scrofa, is now increasingly used as a large animal model to study brain diseases in humans. However, no study has been performed to understand the regulation of the brain-placental axis in a comparative manner between mouse and pig. In the present work, we performed a comparative analysis of single-nuclei gene expression patterns in the placenta and fetal brain between mouse and pig. The placenta and fetal brain cells expressing the common orthologous genes and the species-specific genes were identified in both species. The analysis showed that a relatively fewer number of cell clusters expressed genes in a correlated manner between the placenta and fetal brain of pig relative to that of mouse. The results further showed that specific genes related to visual perception were expressed in specific cell types of the fetal brain of both mouse and pig. These genes were expressed in a coordinated manner with a set of genes expressed in specific cell types of the placenta. Further analysis showed that these placental expressed genes were significantly differentially regulated (P &amp;lt; 0.05, fold changes &amp;gt; 2) in the term-placenta between nocturnal and diurnal animals. Significant enrichment (P &amp;lt; 0.05) of specific binding motifs of known transcription factors, whose functions are related to the specification of retinal cells, was observed in the immediate upstream region of these placenta genes. Phylogenetic analysis of these genes among 29 diverse mammalian species differing in placenta type and activity (nocturnal or diurnal) was performed. The Bayes Traits discrete trait correlation test using the inferred phylogenies and the known trait data identified genes associated with the correlated evolution (Log Bayes Factor &amp;gt; 2) of placenta with animal activity (nocturnal or diurnal). The functional association of these genes with visual perception was evident from differential expression in the ocular cells between pig and mouse. Together, the findings of this study show that the regulation of the brain-placental axis plays a role in the evolution of visual perception function of brain to shape the nocturnal or diurnal activity of placental animals. However, factors other than the brain-placental axis are also known to influence temporal changes in nocturnal or diurnal activity of specific animals. Thus, future studies, potentially applying experimental evolution approaches, are needed to dissect the mechanisms of nocturnal bottleneck in placental animals.

PSII-1 Weaning as prenatal stress: preliminary study on indicators of calf resiliency

Abstract Maternal stressors have been reported to alter fetal development in many species. During pregnancy beef cattle are subjected to different potential stressors, such as weaning their current offspring, as part of beef production practices. The objective of this study was to investigate the relationship between weaning method as a prenatal maternal stress and the effect on offspring resiliency. Multiparous cows were weaned of their calves in the fall of 2022 using either abrupt (A), fenceline (F), or nose-flap (N) weaning methods (n = 30 per group). Calves born from these cows the following spring (2023) were followed for birthweights, morbidity, and mortality. Mean estimated fetal age at exposure was 126 d (range 66 to 219 d) using breed averages for gestational length. Cognitive tests were performed at 2 mo of age using an outdoor arena to continuously monitor calves during 2 min of initial isolation, 2 min exposed to a novel object, and 1 min of exposure to a human in the arena. Tests were performed sequentially, and treatments were balanced across days. Prenatal exposure to A was associated with a 74.8 (2.5 to 2,237.3, P &amp;lt; 0.01) and 21.5 (1.2 to 385.7, P = 0.03) times increase in the odds of calves being stillborn or failure to thrive within 24 h of birth compared with F or N, respectively. There was no difference in morbidity or mortality during d 1 to 60. Birthweights were available on one-half of the calves from each group and showed no statistical difference; however, there was a 4.53 kg numerical difference between A and N groups. Behavioral data from a subset of 36 calves (A = 14, F = 11, and N = 11) was assessed for time spent standing, moving, exploring, duration in the open center vs. perimeter of the arena. There was a tendency for A exposed calves to spend more time in the perimeter after being confronted with a novel object compared with N exposed calves (mean difference of percent of total test time in perimeter from isolation to novel object test: A = 24.0 ± 23.9 %, N = -2.9 ± 22.1 %, P = 0.08). Fenceline exposed calves spent more time moving during initial isolation than either abrupt or nose-flap (69.3 ± 14.7 %, 50.6 ± 11.9 %, and 69.9 ± 17.8 % for A, F, N, respectively (P = 0.01 for A vs F and F vs N). These behavioral and physiological indicators support a potential divergence in survivability and coping mechanisms associated with prenatal exposure to different weaning methods. Future research will evaluate different dimensions of cognitive performance as well as increasing sample size.

387 Impacts of rumen protected omega-6 fatty acid supplementation on cow reproduction and calf growth

Abstract Maternal nutrition during pregnancy is crucial for proper fetal development. Rumen protected omega-6 (ω-6) fatty acids (FA) may improve health and reproductive success in beef cattle. Previous research studied the effects of supplementing ω-6 on cow production either during late gestation or post-breeding but not during both stages. Our objective was to determine the effects of ω-6 supplementation during late gestation and post-breeding on cow reproduction and calf pre-weaning growth. Eighty cows were assigned to either a saturated FA control (C) or rumen protected ω-6 supplements for 40 d before parturition (PRE) and/or 35 d after artificial insemination (AI, POST) using a 2 × 2 factorial: PRE C-POST C(n = 19); PRE C-POST ω-6(n = 19); PRE ω-6-POST ω-6(n = 17); PRE ω-6-POST C(n = 18). Cows were fed ad libitum hay and water when on/off supplementation periods. Supplements were provided in low moisture tubs. Individual animal intake of supplement was measured by a GrowSafe system. Cow body weights and plasma FA concentrations were measured prior to and after supplementation during each period. Calves were weighed at birth, branding, 150 d old and weaning. Reproductive measurements included postpartum estrus activity, estrus response at fixed-time AI (FTAI), and pregnancy rates. Blood plasma for progesterone analysis was collected on d 7 post-AI on all cows. Corpus luteum (CL) area was measured on d 7 via transrectal ultrasonography on a subset of cows during the POST period (PRE ω-6-POST ω-6 n = 8; PRE C-POST C n = 8; PRE C-POST ω-6 n = 8; PRE ω-6-POST C n = 8). The relationship between supplement intake and plasma FA concentration was analyzed via linear regression, and all other variables were analyzed via ANOVA. Supplement intakes within treatments and between the PRE and POST supplemental periods were highly variable. Body weights remained similar for cows (P = 0.52), but POST ω-6 calves had larger weaning weights than POST C calves (P = 0.02). There was a positive linear relationship (r2 = 0.14, P &amp;lt; 0.03) between supplement intake and plasma FA for PRE ω-6 and POST ω-6. Positive linear relationships between intake and plasma ω-6 FA concentration were observed for PRE C (r2 = 0.11, P &amp;lt; 0.05), PRE ω-6 (r2 = 0.2, P &amp;lt; 0.007) and POST ω-6 (r2 = 0.31, P = 0.0005). Post-partum estrus activity was similar (P = 0.81) between PRE C and PRE ω-6 cows, and estrus response at FTAI was similar (P = 0.13) between POST C and POST ω-6 cows. POST ω-6 cows had larger CL areas than POST C cows (P = 0.03); however, blood progesterone concentrations at d 7 did not differ between treatments (P = 0.65). There was no difference in conception to FTAI between POST C and POST ω-6 (P = 0.08). These results indicate that free choice ω-6 FA supplementation during late gestation and post-AI result in large variation in intake between cows that influence plasma concentrations, but did not markedly alter reproductive measures in mature beef cows.