Microbial and metabolomic mechanisms mediating the effects of dietary inulin and cellulose supplementation on porcine oocyte and uterine development

Background Dietary fiber (DF) is often eschewed in swine diet due to its anti-nutritional effects, but DF is attracting growing attention for its reproductive benefits. The objective of this study was to investigate the effects of DF intake level on oocyte maturation and uterine development, to determine the optimal DF intake for gilts, and gain microbial and metabolomic insight into the underlying mechanisms involved. Methods Seventy-six Landrace × Yorkshire (LY) crossbred replacement gilts of similar age (92.6 ± 0.6 d; mean ± standard deviation [SD]) and body weight (BW, 33.8 ± 3.9 kg; mean ± SD) were randomly allocated to 4 dietary treatment groups (n = 19); a basal diet without extra DF intake (DF 1.0), and 3 dietary groups ingesting an extra 50% (DF 1.5), 75% (DF 1.75), and 100% (DF 2.0) dietary fiber mixture consisting of inulin and cellulose (1:4). Oocyte maturation and uterine development were assessed on 19 d of the 2nd oestrous cycle. Microbial diversity of faecal samples was analysed by high-throughput pyrosequencing (16S rRNA) and blood samples were subjected to untargeted metabolomics. Results The rates of oocytes showing first polar bodies after in vitro maturation for 44 h and uterine development increased linearly with increasing DF intake; DF 1.75 gilts had a 19.8% faster oocyte maturation rate and a 48.9 cm longer uterus than DF 1.0 gilts (P < 0.05). Among the top 10 microbiota components at the phylum level, 8 increased linearly with increasing DF level, and the relative abundance of 30 of 53 microbiota components at the genus level (> 0.1%) increased linearly or quadratically with increasing DF intake. Untargeted metabolic analysis revealed significant changes in serum metabolites that were closely associated with microbiota, including serotonin, a gut-derived signal that stimulates oocyte maturation. Conclusions The findings provide evidence of the benefits of increased DF intake by supplementing inulin and cellulose on oocyte maturation and uterine development in gilts, and new microbial and metabolomic insight into the mechanisms mediating the effects of DF on reproductive performance of replacement gilts.

237 Incidence and Implications of Disparate Uterine and Ovarian Development Observed Among Heifers Evaluated During the Peripubertal Period

Rapid development in the reproductive tract occurs in the peripubertal period, with variable rates of development of reproductive tissues potentially resulting in perceived disparities in ovarian and uterine development at pre-breeding examination. Data collected from 22,173 heifers evaluated over five consecutive breeding seasons (2014–2018) were analyzed retrospectively to assess relationships between observed disparities in uterine and ovarian development and the timing of conception within the breeding season. Pre-breeding evaluations were conducted 35–45 days prior to breeding. Weight, hip height, and pelvic area were recorded. A single veterinarian conducted all reproductive evaluations via rectal palpation, and heifers were assigned individual scores for ovarian (2=infantile, 3=no significant structures, 4=large follicle and/or corpus luteum) and uterine (2=infantile, 3=mid-sized, distended tract, 4=well-vascularized, distended or coiled tract) development respectively. Heifers received artificial insemination (AI) based on detected estrus following the 14-day MGA-PG protocol. Pregnancy diagnosis was performed via transrectal ultrasonography. Pregnancy rates to AI (P/AI) were greater for scores 4-4 (n = 14,567) in comparison with 3-3 (n=3,941; P &lt; 0.0001) or 2-2 (n = 44; P &lt; 0.0001) and likewise were greater (P &lt; 0.0001) for scores 3-3 in comparison with 2-2. Heifers with disparate scores of 2–3 (n = 38) did not differ (P = 0.53) from those with disparate scores of 3-2 (n = 53) with respect to P/AI, but either disparity was associated with greater (P &lt; 0.01) P/AI relative to scores of 2-2 and reduced P/AI relative to scores of 3-3 (P &lt; 0.01). Scores of 4-3 (1,698) and 3-3 did not differ (P &gt;0.44) in P/AI, but P/AI tended (P = 0.06) to be greater among scores 3–4 (1,832) in comparison with 3-3. Similar (P &gt; 0.33) P/AI was observed among heifers scored 4-4, 4-3, or 3–4. In summary, disparate ovarian and uterine development impacted timing of conception within the breeding season among heifers with lower tract scores. Such disparities were observed among 0.4% of heifers evaluated.

The development of the human uterus: morphogenesis to menarche

ABSTRACT There is emerging evidence that early uterine development in humans is an important determinant of conditions such as ontogenetic progesterone resistance, menstrual preconditioning, defective deep placentation and pre-eclampsia in young adolescents. A key observation is the relative infrequency of neonatal uterine bleeding and hormone withdrawal at birth. The origin of the uterus from the fusion of the two paramesonephric, or Müllerian, ducts was described almost 200 years ago. The uterus forms around the 10th week of foetal life. The uterine corpus and the cervix react differently to the circulating steroid hormones during pregnancy. Adult uterine proportions are not attained until after puberty. It is unclear if the endometrial microbiome and immune response—which are areas of growing interest in the adult—play a role in the early stages of uterine development. The aim is to review the phases of uterine development up until the onset of puberty in order to trace the origin of abnormal development and to assess current knowledge for features that may be linked to conditions encountered later in life. The narrative review incorporates literature searches of Medline, PubMed and Scopus using the broad terms individually and then in combination: uterus, development, anatomy, microscopy, embryology, foetus, (pre)-puberty, menarche, microbiome and immune cells. Identified articles were assessed manually for relevance, any linked articles and historical textbooks. We included some animal studies of molecular mechanisms. There are competing theories about the contributions of the Müllerian and Wolffian ducts to the developing uterus. Endometrium features are suggestive of an oestrogen effect at 16–20 weeks gestation. The discrepancy in the reported expression of oestrogen receptor is likely to be related to the higher sensitivity of more recent techniques. Primitive endometrial glands appear around 20 weeks. Features of progestogen action are expressed late in the third trimester. Interestingly, progesterone receptor expression is higher at mid-gestation than at birth when features of endometrial maturation are rare. Neonatal uterine bleeding occurs in around 5% of neonates. Myometrial differentiation progresses from the mesenchyme surrounding the endometrium at the level of the cervix. During infancy, the uterus and endometrium remain inactive. The beginning of uterine growth precedes the onset of puberty and continues for several years after menarche. Uterine anomalies may result from fusion defects or atresia of one or both Müllerian ducts. Organogenetic differentiation of Müllerian epithelium to form the endometrial and endocervical epithelium may be independent of circulating steroids. A number of genes have been identified that are involved in endometrial and myometrial differentiation although gene mutations have not been demonstrated to be common in cases of uterine malformation. The role, if any, of the microbiome in relation to uterine development remains speculative. Modern molecular techniques applied to rodent models have enhanced our understanding of uterine molecular mechanisms and their interactions. However, little is known about functional correlates or features with relevance to adult onset of uterine disease in humans. Prepubertal growth and development lends itself to non-invasive diagnostics such as ultrasound and MRI. Increased awareness of the occurrence of neonatal uterine bleeding and of the potential impact on adult onset disease may stimulate renewed research in this area.

AGE AND GENDER DIFFERENCES IN GROWTH OF MASS, LENGTH AND WIDTH OF CALVARIA IN ONTOGENESIS OF ROMANOV BREED SHEEP

This article presents the results of scientific studies of morphometric indicators of calvary in the pre-and postnatal ontogenesis of Romanov breed sheep. Changes related to the sex of experimental animals were also studied. In order to detect general patterns of growth of calvari morphological parameters, the age stages of selecting material for research were determined: from a 2-month-old fetus to 12 months of postnatal life and from adult sheep 5-6 years old. We measured the mass, length and width of the studied material. The data obtained were subjected to statistical processing. The calvary maturity at each age in percentage, was determined. As a result of our studies, we were able to establish that the growth of linear indicators of calvary subjected to general biological laws of a decrease in its intensity with age, i.e. more rapidly, it proceeds in uterine development compared with postnatal. As for the changes in sex-related animals, it was found that growth of mass, length and width of calvary occurs in both sexes simultaneously and with almost the same intensity. In their growth, two decreases are observed: the first - before birth and the second - from 3 to 6 months. Throughout the entire periods of research, the calvary mass in females approaches its final value faster, and its length, on the contrary, in males. As for its width, in uterine development it grows somewhat faster than in females, and after birth in males. By one-year-old age of sheep, none of the calvari indicators in either males or females reaches its definitive state.