Effects of colostrum, feeding method and oral IGF1 on porcine uterine development

Dexamethasone exposure during pregnancy triggers metabolic syndrome in offspring via epigenetic alteration of IGF1

BACKGROUND

Previous research has reported that prenatal exposure to dexamethasone (PDE) results in organ dysplasia and increased disease susceptibility in offspring. This study aimed to investigate the epigenetic mechanism of metabolic syndrome induced by PDE in offspring.

METHODS

Pregnant Wistar rats were administered dexamethasone, and their offspring's serum and liver tissues were analyzed. The hepatocyte differentiation model was established to unveil the molecular mechanism. Neonatal cord blood samples were collected to validate the phenomenon and mechanism.

RESULTS

The findings demonstrated that PDE leads to insulin resistance and typical metabolic syndrome traits in adult offspring rats, which originated from fetal liver dysplasia. Additionally, PDE reduced serum corticosterone level and inhibited hepatic insulin-like growth factor 1 (IGF1) signaling in fetal rats. It further revealed that liver dysplasia and functional impairment induced by PDE persist after birth, driven by the continuous downregulation of serum corticosterone and hepatic IGF1 signaling. Both in vitro and in vivo experiments confirmed that low endogenous corticosterone reduces the histone 3 lysine 9 acetylation (H3K27ac) level of IGF1 and its expression by blocking glucocorticoid receptor α, special protein 1, and P300 into the nucleus, resulting in hepatocyte differentiation inhibition and liver dysplasia. Intriguingly, neonatal cord blood samples validated the link between reduced liver function in neonates induced by PDE and decreased serum cortisol and IGF1 levels.

CONCLUSIONS

This study demonstrated that low endogenous glucocorticoid level under PDE lead to liver dysplasia by downregulating the H3K27ac level of IGF1 and its expression, ultimately contributing to metabolic syndrome in adult offspring.

Effects of colostrum management on transfer of passive immunity and the potential role of colostral bioactive components on neonatal calf development and metabolism

Neonatal dairy and beef calves are required to ingest adequate volumes of high-quality colostrum during their first hours of life to acquire transfer of passive immunity (TPI). As such, immunoglobulin G (IgG) has largely been the focus of colostrum research over recent decades. Yet, little is known about the additional bioactive compounds in colostrum that potentially influence newborn calf development and metabolism. The purpose of this narrative review is to synthesize research regarding the effects of colostrum management practices on TPI, as well as to address the potential role of additional colostral bioactive molecules, including oligosaccharides, fatty acids, insulin, and insulin-like growth factor-I, in promoting calf development and metabolism. Due to the importance of IgG in ensuring calf immunity and health, we review past research describing the process of colostrogenesis and dam factors influencing the concentrations of IgG in an effort to maximize TPI. We also address the transfer of additional bioactive compounds in colostrum and prepartum management and dam factors that influence their concentrations. Finally, we highlight key areas of future research for the scientific community to pursue to ultimately improve the health and welfare of neonatal dairy calves.

A standardized model to study effects of varying 24-h colostrum dose on postnatal growth and development

Survival, feed efficiency, growth, and fertility of swine are dependent on colostrum intake in the first 24 h after birth. This study determined the effects of three doses of a homogeneous colostrum sample on 24-h body weight, rectal temperature (RT), immunocrit, and growth and survival to postnatal day (PND) 7. Three female piglets were selected from eight litters (n = 24 piglets) at birth, removed from their litter, and bottle-fed 10% (COL10, n = 8), 15% (COL15, n = 8), or 20% (COL20, n = 8) colostrum based on birth weight over 12 bottle feedings every 2 h. At 24 h, piglets were weighed, RT recorded, and blood was collected to measure immunocrit. Piglets were returned to the litter of origin, and weight was measured daily until PND 7. Colostrum dose had an overall effect on weight gain at 24 h, RT, immunocrit, and growth to PND 7 (P < 0.05). Piglets in the 20% BrW colostrum group had greater weight gain, RT, and immunocrit at 24 h than COL10 piglets (P < 0.05), but these variables were not different between COL15 and the other treatments. Despite no difference in average daily gain after being returned to their litters, the greater weight (P < 0.05) in COL20 compared to COL10 and COL15 was sustained over 7 d. Seven piglets in each treatment survived to PND 7. This model using standardized doses of a homogeneous colostrum sample enables controlled studies aimed at understanding the role of 24-h colostrum intake on piglet development.

Uterine Glands: Developmental Biology and Functional Roles in Pregnancy

All mammalian uteri contain glands in the endometrium that develop only or primarily after birth. Gland development or adenogenesis in the postnatal uterus is intrinsically regulated by proliferation, cell-cell interactions, growth factors and their inhibitors, as well as transcription factors, including forkhead box A2 (FOXA2) and estrogen receptor α (ESR1). Extrinsic factors regulating adenogenesis originate from other organs, including the ovary, pituitary, and mammary gland. The infertility and recurrent pregnancy loss observed in uterine gland knockout sheep and mouse models support a primary role for secretions and products of the glands in pregnancy success. Recent studies in mice revealed that uterine glandular epithelia govern postimplantation pregnancy establishment through effects on stromal cell decidualization and placental development. In humans, uterine glands and, by inference, their secretions and products are hypothesized to be critical for blastocyst survival and implantation as well as embryo and placental development during the first trimester before the onset of fetal-maternal circulation. A variety of hormones and other factors from the ovary, placenta, and stromal cells impact secretory function of the uterine glands during pregnancy. This review summarizes new information related to the developmental biology of uterine glands and discusses novel perspectives on their functional roles in pregnancy establishment and success.

Review: Maternal programming of development in the pig and the lactocrine hypothesis

Maternal effects on development are profound. Together, genetic and epigenetic maternal effects define the developmental trajectory of progeny and, ultimately, offspring phenotype. Maternally provisioned environmental conditions and signals affect conceptus, fetoplacental and postnatal development from the time of conception until weaning. In the pig, reproductive tract development is completed postnatally. Porcine uterine growth and uterine endometrial development occur in an ovary-independent manner between birth (postnatal day = PND 0) and PND 60. Milk-borne bioactive factors (MbFs), exemplified by relaxin, communicated from lactating dam to nursing offspring via a lactocrine mechanism, represent an important source of extraovarian uterotrophic support in the neonatal pig. Lactocrine deficiency from birth affects both the neonatal porcine uterine developmental program and trajectory of uterine development, with lasting consequences for endometrial function and uterine capacity in adult female pigs. The potential lactocrine signaling window extends from birth until the time of weaning. However, it is likely that the maternal lactocrine programming window - that period when MbFs communicated to nursing offspring have the greatest potential to affect critical organizational events in the neonate - encompasses a comparatively short period of time within 48 h of birth. Lactocrine deficiency from birth was associated with altered patterns of endometrial gene expression in neonatally lactocrine-deficient adult gilts during a critical period for conceptus-endometrial interaction on pregnancy day 13, and with reduced litter size, estimated at 1.4 pigs per litter, with no effect of parity. Data were interpreted to indicate that reproductive performance of female pigs that do not receive sufficient colostrum from birth is permanently impaired. Observations to date suggest that lactocrine-dependent maternal effects program postnatal development of the porcine uterus, endometrial functionality and uterine capacity. In this context, reproductive management strategies and husbandry guidelines should be refined to ensure that such practices promote environmental conditions that will optimize uterine capacity and fecundity. This will entail careful consideration of factors affecting lactation, the quality and abundance of colostrum/milk, and practices that will afford neonatal pigs with the opportunity to nurse and consume adequate amounts of colostrum.

Differential microRNA Expression in Porcine Endometrium Involved in Remodeling and Angiogenesis That Contributes to Embryonic Implantation

Background: In western swine breeds, up to 30% of embryonic losses occur during early pregnancy, and the majority of embryonic losses happens during implantation. In this period, maternal recognition of pregnancy begins to occur and blastocysts undergo dramatic morphologic changes. As with other species, changes in the uterine environment plays an important role in the process of embryo implantation in pigs. Erhualian (ER) pigs, one of the Chinese Taihu swine breeds, are known to have the highest litter size in the world. Experiments demonstrated that the greater embryonic survival on gestation day (GD) 12 in Chinese Taihu pigs is one important factor that contributes to enhanced litter size. This is largely controlled by maternal genes. In this study, endometrial samples were collected from pregnant Landrace×Large Yorkshire (LL) sows (parity 3) and ER sows (parity 3) on GD12 and the expression profiles of microRNAs (miRNAs) in the endometrium were compared between ER and LL using miRNA-seq technology. Results: A total of 288 miRNAs were identified in the pig endometrium, including 202 previously known and 86 novel miRNAs. The Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that highly abundant miRNAs might affect endometrial remodeling. Comparison between LL and ER sows revealed that 96 known miRNAs were differentially expressed between the two groups (including 78 up-regulated and 18 down-regulated miRNAs in ER compared to LL). Bioinformatics analysis showed that the target genes of some differentially expressed miRNAs were involved in pathways related to angiogenesis, proliferation, apoptosis, and tissue remodeling, which play critical roles in implantation by regulating endometrial structural changes and secretions of hormones, growth factors, and nutrients. Furthermore, the results demonstrated that insulin-like growth factor-1 protein expression was directly inhibited by miR-206. The lower expression of miR-206 in ER compared to LL might facilitate the angiogenesis of the endometrium during embryo implantation. Conclusions: The identified miRNAs that are differentially expressed in the endometrium of ER and LL pigs will contribute to the understanding of the role of miRNAs in embryonic implantation and the molecular mechanisms of the highest embryonic survival in Chinese ER pigs.

Development and Function of Uterine Glands in Domestic Animals

All mammalian uteri contain glands that synthesize or transport and secrete substances into the uterine lumen. Uterine gland development, or adenogenesis, is uniquely a postnatal event in sheep and pigs and involves differentiation of glandular epithelium from luminal epithelium, followed by invagination and coiling morphogenesis throughout the stroma. Intrinsic transcription factors and extrinsic factors from the ovary and pituitary as well as the mammary gland (lactocrine) regulate uterine adenogenesis. Recurrent pregnancy loss is observed in the ovine uterine gland knockout sheep, providing unequivocal evidence that glands and their products are essential for fertility. Uterine gland hyperplasia and hypertrophy during pregnancy are controlled by sequential actions of hormones from the ovary and/or pituitary as well as the placenta. Gland-derived histotroph is transported by placental areolae for fetal growth. Increased knowledge of uterine gland biology is expected to improve pregnancy outcomes, as well as the health and productivity of mothers and their offspring.