Chronic Undernutrition in Ovine Twin Pregnancies Abolishes Differences in Birth Weight Due to Sex: An Evaluation of the Role of Nutritional and Antioxidant Supplementation.

In twin pregnancies of discordant sex, the male fetus grows larger than the female co-twin. Our study aimed to determine the effect of the sex of co-twins on lambs' birth weight in ovine pregnancies developed under natural undernourishment. Additionally, we investigated whether the nutritional and/or antioxidant supplementation provided to ewes during pregnancy could modulate the potential effects associated with the sex of co-twins. Ninety-six birth records of twin pregnancies of sheep grazing the natural Patagonian prairies were analyzed. The animals were divided into four groups: control (no supplementation), N (concentrate supplementation, 100% NRC), A (antioxidant supplementation), and NA (concentrate + antioxidant supplementation). Supplementation occurred from day 35 of gestation onwards until lambing. There were no differences in female or male birth weight in the control undernourished group. However, in group N, females or males with sex-discordant co-twins had a higher birth weight than did those with co-twins of the same sex. Group A males with female co-twins had a higher birth weight compared to males whose co-twins were also males. In NA lambs, males had a higher birth weight compared to females, regardless of their co-twin's sex. Therefore, chronic undernutrition abolished the differences in birth weight due to fetal sex. Restoring maternal nutrition or antioxidant supplementation tends to normalize birth weight and restore the differences between females and males. This effect is enhanced with the combined supplementation of concentrated food and antioxidants.

Bovine Peripheral Blood-Derived Mesenchymal Stem Cells (PB-MSCs) and Spermatogonial Stem Cells (SSCs) Display Contrasting Expression Patterns of Pluripotency and Germ Cell Markers under the Effect of Sertoli Cell Conditioned Medium.

In vitro gamete derivation has been proposed as an interesting strategy for treatment of infertility, improvement of genetic traits, and conservation of endangered animals. Spermatogonial stem cells (SSCs) are primary candidates for in vitro gamete derivation; however, recently, mesenchymal stem cells (MSCs) have also been proposed as candidates for germ cell (GCs) differentiation mainly due to their transdifferentiating capacity. The objective of the present study was to compare the potential for GC differentiation of bovine peripheral blood-derived MSCs (PB-MSCs) and SSCs under the effect of conditioned medium (CM) derived from Sertoli cells (SCs/CM). Samples were collected every 7 days for 21 days and analyzed for pluripotent, GC, and MSC marker expression. The absence of OCT4 and the increased (p < 0.05) expression of NANOG seems to play a role in SSC differentiation, whereas the absence of NANOG and the increased expression (p < 0.05) of OCT4 may be required for PB-MSC differentiation into GCs. SSCs cultured with SCs/CM increased (p < 0.05) the expression of PIWIL2 and DAZL, while PB-MSCs cultured under the same condition only increased (p < 0.05) the expression of DAZL. Overall, the patterns of markers expression suggest that PB-MSCs and SSCs activate different signaling pathways after exposure to SCs/CM and during differentiation into GCs.

Dynamic Expression of Follicle-Stimulating Hormone and Estrogen mRNA Receptors Associated with microRNAs 34a and -let-7c in Canine Follicles during the Estrous Cycle.

The genes encoding for estrogen receptor (ESR2) and follicle-stimulating hormone receptor (FSHR) play crucial roles in ovarian follicular development. This study aimed to determine the expression levels of miRNAs predicted against FSHR and ESR2 mRNAs in follicular cells related to their target genes during the estrous cycle in canines. Antral follicles were dissected from 72 ovaries following ovariohysterectomies. MiRNAs regulating FSHR and ESR2 genes were selected from miRNA databases, and mature miRNA and mRNA expression profiling was performed using real-time polymerase chain reaction (PCR). The best miRNA for each target gene was selected considering the quantitative PCR (qPCR) performance and target prediction probability, selecting only miRNAs with a binding p-value of 1.0, and choosing cfa-miR-34a and cfa-let-7c for FSHR and ESR2, respectively. The expression levels comparing the different phases of the estrous cycle were evaluated using ANOVA. Pearson correlations between the expression pattern of each miRNA and their target genes were performed. Each miRNA and its target genes were expressed in the granulosa cells in all estrous phases. FSHR remained low in anestrus and proestrus, increased (p < 0.05) to the highest level in estrus, and decreased (p < 0.05) in diestrus. ESR2 showed the same trend as FSHR, with the highest (p < 0.05) expression in estrus and the lowest (p < 0.05) in anestrus and proestrus. A tendency for an inverse relationship was observed between the expression of miR-34a and FSHR only in the anestrus phase, while an inverse correlation (r = -0.8) was found between miRNA-7c and ESR2 (p < 0.01). The expression profile of miR-34a and miR-let-7c and their predicted target genes of dog ovarian follicles throughout the estrous cycle observed in this study suggest a role in the transcriptional regulation of FSHR and ESR2, which is the first evidence of the involvement of these miRNAs in the canine follicular function.

Bovine adipose tissue-derived mesenchymal stem cells self-assemble with testicular cells and integrates and modifies the structure of a testicular organoids.

Mesenchymal stem cells (MSC) display self-renewal and mesodermal differentiation potentials. These characteristics make them potentially useful for in vitro derivation of gametes, which may constitute experimental therapies for human and animal reproduction. Organoids provide a spatial support and may simulate a cellular niche for in vitro studies. In this study, we aimed at evaluating the potential integration of fetal bovine MSCs derived from adipose tissue (AT-MSCs) in testicular organoids (TOs), their spatial distribution with testicular cells during TO formation and their potential for germ cell differentiation. TOs were developed using Leydig, Sertoli, and peritubular myoid cells that were previously isolated from bovine testes (n = 6). Thereafter, TOs were characterized using immunofluorescence and Q-PCR to detect testicular cell-specific markers. AT-MSCs were labeled with PKH26 and then cultured with testicular cells at a concentration of 1 × 106 cells per well in Ultra Low Attachment U-shape bottom (ULA) plates. TOs formed by testicular cells and AT-MSCs (TOs + AT-MSCs) maintained a rounded structure throughout the 28-day culture period and did not show significant differences in their diameters. Conversely, control TOs exhibited a compact structure until day 7 of culture, while on day 28 they displayed cellular extensions around their structure. Control TOs had greater (P < 0.05) diameters compared to TOs + AT-MSCs. AT-MSCs induced an increase in proportion of Leydig and peritubular myoid cells in TOs + AT-MSCs; however, did not induce changes in the overall gene expression of testicular cell-specific markers. STAR immunolabelling detected Leydig cells that migrated from the central area to the periphery and formed brunches in control TOs. However, in TOs + AT-MSCs, Leydig cells formed a compact peripheral layer. Sertoli cells immunodetected using WT1 marker were observed within the central area forming clusters of cells in TOs + AT-MSCs. The expression of COL1A associated to peritubular myoids cells was restricted to the central region in TOs + AT-MSCs. Thus, during a 28-day culture period, fetal bovine AT-MSCs integrated and modified the structure of the TOs, by restricting formation of branches, limiting the overall increase in diameters and increasing the proportions of Leydig and peritubular myoid cells. AT-MSCs also induced a reorganization of testicular cells, changing their distribution and particularly the location of Leydig cells.

Colostrum traits and newborn body weight and growth: comparison between single and twin underfed sheep pregnancies.

Maternal nutrition during gestation plays an important role in colostrum production, postnatal growth, and survival of newborn lambs, especially in twin gestations. This research aimed to investigate the effects of chronic natural undernutrition on colostrum traits and early lamb's postnatal growth born from single and twin sheep pregnancies developed in a restrictive prairie, representative of southern Patagonia. Single- and twin-bearing ewes (n = 20 per group) were maintained grazing in a natural pasture. At 140 days of gestation, ewes were placed in individual pens for lambing control. Colostrum was collected immediately after delivery and at 12, 24, and 36 h postpartum, for determination of yield and composition. Maternal blood was obtained at 140 days of gestation and at lambing for plasma glucose, progesterone, 17ß-estradiol, and IgG determination. Newborn lamb blood for determining glycaemia and IgG was collected at birth and at 12, 24, 36, and 120 h after birth. Lamb mortality and growth was assessed from birth until 30 days of life. No differences were observed in progesterone and 17ß-estradiol. There were no differences in colostrum yields and fat components, however single- had higher values of protein and lactose than twin-bearing ewes (p < 0.05 for both). Singletons had higher glycaemia than twins at 12 h postpartum (102.2 ± 32.8 vs. 73.4 ± 29.9 mg/dL, p < 0.05). Colostrum IgG content was similar at delivery but higher in single ewes at 12 and 24 h, reaching a similar values at 36 h (4.7 ± 9.7 and 5.8 ± 7.7 mg/mL in single and twin pregnancies, respectively). Newborn IgG was higher in singletons compared to twins at least until 48 h of life. Lams body weight was always superior in singleton than twins from birth until 30 days of life. Mortality did not differ during the first week of life, but it increased significantly only in twins until day 30 of life. Undernourishment in pregnant ewes affected colostrum quantity and quality, resulting in a lower postnatal growth and a higher mortality in twins. Alternative managements favoring fetal growth, birth weight and neonatal viability in twin sheep pregnancies are needed, when flocks are breed under harsh environments.

Effect of progesterone on in vitro meiotic maturation of canine oocytes associated with Cx37 and Cx43 gene expression.

Progesterone (P4) concentrations in canines are exceptionally high in the periovulatory period. However, the mechanisms by which P4 modulates final oocyte development in dogs remain to be characterized. The aim of this study was to evaluate the effect of P4 on meiotic development related to the gene expression of connexin 37 (Cx37) and connexin 43 (Cx43) in the canine cumlus oocyte complexes (COCs). COCs were isolated from 120 canine ovaries after a routine ovariohysterectomy. In each experiment, groups of COCs retrieved from the antral follicles were subjected to in vitro maturation (IVM) for 72 h without (control) or with P4 (50 µg/mL and 100 µg/mL) or the P4 receptor antagonist, aglepristone (RU534 at 1 µM and 10 µM). Some of the COCs recovered (from each group) after 72 h of IVM were subjected to meiotic evaluation; the remaining COCs, and those not subjected to IVM, were used to analyze the gene expression of Cx37 and Cx43 by qPCR. The results were evaluated using ANOVA. The addition of P4 increased (P < 0.05) the meiotic development compared to that in the control or aglepristone groups. The highest (P < 0.05) percentage of oocytes in the MII stage was observed upon P4 supplementation. In contrast, the highest percentage (P < 0.05) of oocytes arrested in the GV stage and the lowest (P < 0.05) percentages in the MII stage were observed for COCs cultured with aglepristone. Although a significant decrease in the mRNA levels of both connexins was observed after culturing, no effect on Cx37 and Cx43 gene expression was observed when exogenous P4 was added compared to those of the control group. However, COCs cultured with aglepristone exhibited higher (P < 0.05) expression of Cx37 and Cx43 than COCs in the control IVM-group, regardless of the concentration. In conclusion, our results suggest that a high dosage of P4 during IVM enhances the nuclear maturation of canine oocytes without altering the gene expression levels of Cx37 and Cx43. However, the increase in their expression upon treatment with a P4 antagonist indicates an in vivo role for this hormone in the endogenous modulation of both Cx37 and Cx43.

Meiotic Development of Canine Oocytes from Poly-Ovular and Mono-Ovular Follicles after In Vitro Maturation.

Poly-ovular follicles are defined as those with more than one oocyte present in single follicles. The occurrence frequency of this follicle type is higher in canines than that in other species. This study aimed to evaluate the in vitro meiotic maturation of dog oocytes from this follicle type in comparison to those from mono-ovular follicles of various sizes (small antral, medium antral, and large antral) considering different phases of the estrus cycle (anestrus, proestrus, estrus, and diestrus). Canine oocytes were obtained separately from the poly-ovular and mono-ovular antral follicles from the ovaries of adult females. In each experimental replicate, cumulus-oocyte complexes (COCs) from poly-ovular and mono-ovular follicles were incubated in supplemented TCM-199 at 38.5 °C and 5% CO2 for 72 h. After culturing, the meiotic development of each oocyte was evaluated using epifluorescence microscopy. Meiotic stages were classified into germinal vesicle (GV), germinal vesicle breakdown (GVBD), first metaphase (MI), and second metaphase (MII). Data were evaluated using an analysis of variance. Oocytes from poly-ovular follicles at all phases exhibited a higher (p < 0.05) percentage of oocytes arrested at the GV stage than those from mono-ovular follicles, showing the highest rate of GV in small antral follicles during anestrus. In contrast, there were no differences in MII rates (p < 0.05) in oocytes from mono-ovular and poly-ovular follicles during the estrus and diestrus phases in all sizes evaluated, with the highest MII rate in estrus. These results suggest that oocytes from poly-ovular follicles can resume meiosis at a slower rate than those from mono-ovular follicles; however, the maturation in vitro of such oocytes is possible. Furthermore, the relationship between the maturation capacity of oocytes from both poly-ovular and mono-ovular follicles depends on the ovarian cycle and follicular development.

Comparative Analysis of the Potential for Germ Cell (GC) Differentiation of Bovine Peripheral Blood Derived-Mesenchymal Stem Cells (PB-MSC) and Spermatogonial Stem Cells (SSC) in Co-Culture System with Sertoli Cells (SC).

Although spermatogonial stem cells (SSC) constitute primary candidates for in vitro germ cell (GC) derivation, they are scarce and difficult to maintain in an undifferentiated state. Alternatively, mesenchymal stem cells (MSC) are also candidates for GC derivation due to their simplicity for culture and multipotential for transdifferentiation. The aim of the present study was to compare the GC differentiation potentials of bull peripheral blood-derived MSC (PB-MSC) and SSC using an in vitro 3D co-culture system with Sertoli cells (SC). Samples of PB-MSC or SSC co-cultures with SC were collected on days 0, 7, 14 and 21 and analyzed for pluripotency, GC and mesenchymal marker expression. Co-culture of PB-MSC+SC resulted in down-regulation of NANOG and up-regulation of OCT4 at day 7. In comparison, co-culture of SSC+SC resulted in consistent expression of NANOG, OCT4 and SOX2 at day 14. During co-culture, SSC+SC increased the expression of DAZL, PIWIL2, FRAGILIS and STELLA and activated the expression of STRA8, whereas co-culture of PB-MSC+SC only increased the expression of DAZL and PIWIL2. Thus, co-culture of bull PB-MSC+SC and SSC+SC in 3D SACS results in differential expression of pluripotency and GC markers, where bull SSC display a more robust GC differentiation profile compared to PB-MSC.

Generation and Characterization of Bovine Testicular Organoids Derived from Primary Somatic Cell Populations.

Organoids are 3D-culture systems composed of tissue-specific primary cells that self-organize and self-renew, creating structures similar to those of their tissue of origin. Testicular organoids (TOs) may recreate conditions of the testicular niche in domestic and wild cattle; however, no previous TO studies have been reported in the bovine species. Thus, in the present study, we sought to generate and characterize bovine TOs derived from primary testicular cell populations including Leydig, Sertoli and peritubular myoid cells. Testicular cells were isolated from bovine testes and cultured in ultra-low attachment (ULA) plates and Matrigel. TOs were cultured in media supplemented from day 3 with 100 ng/mL of BMP4 and 10 ng/mL of FGF2 and from day 7 with 15 ng/mL of GDNF. Testicular cells were able to generate TOs after 3 days of culture. The cells positive for STAR (Leydig) and COL1A (peritubular myoid) decreased (p < 0.05), whereas cells positive for WT1 (Sertoli) increased (p < 0.05) in TOs during a 28-day culture period. The levels of testosterone in media increased (p < 0.05) at day 28 of culture. Thus, testicular cells isolated from bovine testes were able to generate TOs under in vitro conditions. These bovine TOs have steroidogenic activity characterized by the production of testosterone.

Oxidative Stress and Fetal Growth Restriction Set Up Earlier in Undernourished Sheep Twin Pregnancies: Prevention with Antioxidant and Nutritional Supplementation.

Hypoxemia and oxidative stress, resulting in intrauterine growth restriction (IUGR) in undernourished twin sheep pregnancies, has been described in near-term studies. Our aim was to evaluate if the counteractive effects of maternal nutritional or antioxidant supplementation on the fetal redox status were evident before the accelerated fetal growth phase. Forty twin-bearing ewes grazing on natural Patagonian prairie were randomly assigned to four groups (n = 10 each; P: control ewes consuming mainly natural pasture; P+A: pasture plus antioxidants; P+C: pasture plus concentrate; P+A+C: pasture plus antioxidants and concentrate). Daily herbal antioxidants were supplemented in a feedstuff concentrate as a premix from day 35 until day 100 of gestation, when fetal venous cord blood samples and biometric measurements were obtained via cesarean section. The fetuses from group P were clearly hypoxemic. An analysis of variance showed that maternal antioxidant supplementation showed a trend of increased PO2, SatHb, and Ht, effects not observed in P+C fetuses. Antioxidants decreased the fetal MDA concentration (p < 0.05). Fetal TAC was increased by the antioxidants and concentrate (p < 0.05). Antioxidant supplementation showed a trend to increase fetal body weight but not biometry. The results suggest that negative effects of oxidative stress occur earlier than the overt growth arrest, and the maternal administration of antioxidants may constitute a good nutritional strategy for the early prevention of IUGR.

Flow cytometric evaluation of canine follicular cell apoptosis during the oestrous cycle.

Apoptosis is the cellular mechanism of ovarian follicular atresia in mammals; the aim of this study was to examine the apoptosis-related cyclic changes in follicular cells of different-sized antral follicles throughout the oestrous cycle in canines. Ovaries were collected from 26 adult female dogs (1-4 years) following routine ovariohysterectomy. Antral follicles were classified as small, medium or large antral or preovulatory. The percentage of apoptotic cells was determined flow cytometrically using the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP) DNA nick end labelling (TUNEL) assay. Apoptosis rate was quantified as the percentage of TUNEL-positive cells on a logarithmic scale. Percentages of TUNEL-positive cells obtained in the flow cytometric assay were compared among oestrous phases and follicular sizes using analysis of variance. Apoptotic follicles were observed in all types of canine follicles in different cycle phases and stages of development, possibly corresponding to the physiological process of the oestrous cycle. Both the oestrous phase and follicular size significantly influenced the apoptosis rate (p < .05). Apoptosis rate increased significantly (p < .05) as follicular development progressed. Apoptosis rate was the highest in large follicles during the oestrous phase (9.2%; p < .05) and the lowest in small follicles during the anestrus period (1.8%; p < .05). In conclusion, our results demonstrate significant differences in the apoptosis rate during the oestrous cycle related to follicle development in the canine ovary. Furthermore, flow cytometry using the TUNEL assay was found to be an effective method for detecting apoptosis in canine follicles.

New Insights in Canine Reproduction.

Reproduction in canids has been characterized by having some peculiar aspects, such as the extended reproductive cycle and ovulation of immature oocytes [...].

Overexpression of DAZL, STRA8, and BOULE Genes and Treatment With BMP4 or Retinoic Acid Modulate the Expression of MSC Overexpressing Germ Cell Genes.

In vitro gamete derivation from stem cells has potential applications in animal reproduction as an alternative method for the dissemination of elite animal genetics, production of transgenic animals, and conservation of endangered species. Mesenchymal stem cells (MSCs) may be suitable candidates for in vitro gamete derivation considering their differentiative capacity and their potential for cell therapy. Due to its relevance in gametogenesis, it has been reported that retinoic acid (RA) and bone morphogenetic protein (BMP) 4 are able to upregulate the expression of specific markers associated to the early stages of germ cell (GCs) differentiation in bovine fetal MSCs (bfMSCs). In the present study, we used polycistronic vectors containing combinations of GC genes DAZL, STRA8, and BOULE followed by exposure to BMP4 or RA to induce GC differentiation of bovine fetal adipose tissue-derived MSC (AT-MSCs). Cells samples at Day 14 were analyzed according to the expression of pluripotent genes NANOG and OCT4 and GC genes DAZL, STRA8, BOULE, PIWI, c-KIT, and FRAGILIS using Q-PCR. Fetal and adult testis and AT-MSCs samples were also analyzed for the expression of DAZL, STRA8, and NANOG using immunofluorescence. Increased gene expression levels in the adult testis and cell-specific distribution of DAZL, STRA8, and NANOG in the fetal testis suggest that these markers are important components of the regulatory network that control the in vivo differentiation of bovine GCs. Overexpression of DAZL and STRA8 in bi-cistronic and DAZL, STRA8, and BOULE in tri-cistronic vectors resulted in the upregulation of OCT4, NANOG, and PIWIL2 in bovine fetal AT-MSCs. While BMP4 repressed NANOG expression, this treatment increased DAZL and c-KIT and activated FRAGILIS expression in bovine fetal AT-MSCs. Treatment with RA for 14 days increased the expression of DAZL and FRAGILIS and maintained the mRNA levels of STRA8 in bovine fetal AT-MSCs transfected with bi-cistronic and tri-cistronic vectors. Moreover, RA treatment repressed the expression of OCT4 and NANOG in these cells. Thus, overexpression of DAZL, STRA8, and BOULE induced the upregulation of the pluripotent markers and PIWIL2 in transfected bovine fetal AT-MSCs. The partial activation of GC gene expression by BMP4 and RA suggests that both factors possess common targets but induce different gene expression effects during GC differentiation in overexpressing bovine fetal AT-MSCs.

Maternal Supplementation with Herbal Antioxidants during Pregnancy in Swine.

The effects of a combined supplementation with herbal antioxidants during pregnancy on reproductive traits and piglet performance (number of live, dead, and mummified newborns and litter weight at birth and individual body weight at both birth and weaning) were assessed in a total of 1027 sows (504 treated and 523 control females) kept under commercial breeding conditions. The supplementation increased the number of live-born piglets (13.64 ± 0.11 vs. 12.96 ± 0.13 in the controls; p = 0.001) and the total litter weight, decreasing the incidence of low-weight piglets without affecting the number of stillbirths and mummified newborns. Such an effect was modulated by the number of parity and the supplementation, with supplementation increasing significantly the number of living newborns in the first, second, sixth, and seventh parities (0.87, 1.10, 1.49, and 2.51 additional piglets, respectively; p < 0.05). The evaluation of plasma vitamin concentration and biomarkers of oxidative stress (total antioxidant capacity, TAC, and malondialdehyde concentration, MDA) performed in a subset of farrowing sows and their lighter and heavier piglets showed that plasma levels of both vitamins were significantly higher in the piglets than in their mothers (p < 0.05 for vitamin C and p < 0.005 for vitamin E), with antioxidant supplementation increasing significantly such concentrations. Concomitantly, there were no differences in maternal TAC but significantly higher values in piglets from supplemented sows (p < 0.05). On the other hand, supplementation decreased plasma MDA levels both in the sows and their piglets (p < 0.05). Finally, the piglets from supplemented mothers showed a trend for a higher weaning weight (p = 0.066) and, specifically, piglets with birth weights above 1 kg showed a 7.4% higher weaning weight (p = 0.024). Hence, the results of the present study, with high robustness and translational value by offering data from more than 1000 pregnancies under standard breeding conditions, supports that maternal supplementation with herbal antioxidants during pregnancy significantly improves reproductive efficiency, litter traits, and piglet performance.

Expression Profiles of the Progesterone Receptor, Cyclooxygenase-2, Growth Differentiation Factor 9, and Bone Morphogenetic Protein 15 Transcripts in the Canine Oviducts during the Oestrous Cycle.

The gene expression in the canine oviduct, where oocyte maturation, fertilization, and early embryonic development occur, is still elusive. This study determined the oviductal expression of (PR), cyclooxygenase-2 (COX-2), growth differentiation factor 9 (GDF-9), and bone morphogenetic protein 15 (BMP-15) during the canine oestrous cycle. Samples were collected from bitches at anoestrus (9), proestrus (7), oestrus (8), and dioestrus (11), after routine ovariohysterectomy and the ovarian surface structures and plasma progesterone concentration evaluated the physiological status of each donor. The oviductal cells were isolated and pooled. Total RNA was isolated, and gene expression was assessed by qPCR followed by analysis using the t-test and ANOVA. The PR mRNA increased (P < 0.05) from the anoestrus to dioestrus with the plasma progesterone concentration (r = 0.8). COX-2 mRNA expression was low in the anoestrus and proestrus, and negligible in the oestrus, while it was around 10-fold higher (P < 0.05) in the dioestrus. The GDF-9 mRNA was expressed during all phases of the oestrous cycle and was most abundant (P < 0.05) during oestrus phase. The BMP-15 mRNA decreased (P < 0.05) in the anoestrus and proestrus phases. Thus, the transcripts were differentially expressed in a stage-dependent manner, suggesting the importance of oestrous cycle regulation for successful reproduction in dogs.

Gene and protein expression of connexins 37 and 43 in cumulus-oocytes complexes throughout the canine oestrous cycle.

The aim of this study was to evaluate the expression of connexin (Cx) 37 and Cx43 in canine cumulus-oocyte complexes (COCs) during the oestrous cycle. Cx localisation was analysed by immunohistochemistry and immunofluorescence, whereas protein and gene expression was evaluated by western blotting and quantitative polymerase chain reaction respectively; comparisons were made using analysis of variance. Both Cx37 and Cx43 were expressed in all follicular stages; Cx43 was identified in cumulus cells and Cx37 was identified in cumulus cells, zonae pellucida and oocytes. Immunofluorescence analyses showed that Cx37 remained unchanged during the preovulatory stage but decreased after ovulation, whereas Cx43 remained unchanged before and after ovulation. Cx43 transcripts increased (P<0.05) during anoestrus and dioestrus in medium-sized follicles but remained unaltered during the pro-oestrus and antral stages during oestrus, before and after ovulation. Cx37 mRNA levels decreased in ovulated COCs (P<0.05). The highest levels of Cx37 protein (P<0.05) were detected in the preantral stage during anoestrus. In contrast, strong Cx43 signals were detected in oestrus and in medium-sized antral follicles in dioestrus (P<0.05). Overall, we demonstrated that Cx37 and Cx43 exhibit different expression patterns, suggesting specific roles throughout growth. Maintenance of Cx expression before ovulation indicates the involvement of Cx37 and Cx43 in the prolonged meiotic arrest.

Supplementation of Underfed Twin-Bearing Ewes with Herbal Vitamins C and E: Impacts on Birth Weight, Postnatal Growth, and Pre-Weaning Survival of the Lambs.

Twin-bearing pregnancies of sheep reared in harsh environmental conditions result in maternal undernutrition and feto-maternal oxidative stress, leading to intrauterine growth restriction (IUGR). We assessed the efficiency of supplementation with antioxidant herbal vitamins C and E alone or in combination with concentrate throughout gestation on pregnancy outcomes, pre-weaning growth, and survival of twin lambs from grazing ewes at the Magellan Steppe. Four groups (n = 30 each) of twin-bearing ewes received a base natural prairie (P) diet, supplemented with either herbal vitamins C 500 mg and E 350 IU per day (V) or concentrated food (S); groups were: P, P + V, P + S, and P + VS. Vitamins and concentrate were supplemented until parturition. At birth, lambs were weighed, and blood was drawn for total antioxidant capacity (TAC) evaluation. Lamb body weight (BW) and survival rate were evaluated at mid-lactation (60 days) and at weaning (120 days). Vitamin supplementation resulted in increased lamb birth weight and TAC, with a trend towards higher BW at weaning, while nutritional supplementation only had a positive effect on birth weight. Lamb survival was higher in both vitamin supplemented groups. In conclusion, supplementation with herbal vitamins C and E alone or in combination with concentrate food during pregnancy may constitute a good nutritional strategy for sheep reared in harsh environmental conditions.

GDF-9 and BMP-15 mRNA Levels in Canine Cumulus Cells Related to Cumulus Expansion and the Maturation Process.

The competence to undergo expansion is a characteristic of cumulus cells (CCs). The aim was to investigate the expression of GDF-9 and BMP-15 mRNA in canine cumulus cells in relation to cumulus expansion and meiotic development over the estrous cycle. CCs were recovered from nonmatured and in vitro-matured (IVM) dog cumulus oocyte complexes (COCs), which were obtained from antral follicles at different phases of the estrous cycle. Quantitative real-time polymerase chain reaction (q-PCR) was used to evaluate the relative abundance of GDF-9 and BMP-15 transcripts from the CCs with or without signs of expansion. The results were evaluated by ANOVA and logistic regression. The maturity of the oocyte and the expansion process affected the mRNA levels in CCs. There were differences (p < 0.05) in GDF-9 and BMP-15 gene expression in CCs isolated from nonmatured COCs when comparing the reproductive phases. Lower mRNA levels (p < 0.05) were observed in anestrus and proestrus in comparison to those in estrus and diestrus. In contrast, when comparing GDF-9 mRNA levels in IVM COCs, no differences were found among the phases of the estrous cycle in expanded and nonexpanded CCs (p < 0.05). However, the highest (p < 0.05) BMP-15 gene expression in CCs that did not undergo expansion was exhibited in anestrus and the lowest (p < 0.05) expression was observed in estrus in expanded CCs. Although the stage of the estrous cycle did not affect the second metaphase (MII )rates, the expanded CCs obtained at estrus coexisted with higher percentages of MII (p < 0.05). In conclusion, the differential expression patterns of GDF-9 and BMP-15 mRNA transcripts might be related to cumulus expansion and maturation processes, suggesting specific regulation and temporal changes in their expression.

Maternal Supplementation with Antioxidant Vitamins in Sheep Results in Increased Transfer to the Fetus and Improvement of Fetal Antioxidant Status and Development.

Twinning and maternal nutritional restriction leads to fetal hypoxia, oxidative stress, and intrauterine growth restriction (IUGR) in near-term sheep pregnancies. Our aim was to determine the effect of oral supplementation of vitamins C and E in pregnant sheep on maternal and umbilical cord blood concentrations of vitamins C and E and the effects on fetal antioxidant status, growth, and placental efficiency. Sixteen single- and sixteen twin-bearing ewes, grazing natural Patagonian prairies, were selected after transrectal ultrasound at day 30 after mating. Half of ewes from each pregnancy rank were supplemented daily with vitamins C and E, administered orally, from 30 to 140 days of gestation, when maternal jugular and fetal venous cord blood samples were obtained during cesarean section. Fetuses were weighed and sexed. Placental weight in each fetus was also obtained. Blood plasma was harvested for measurements of maternal and fetal vitamins concentration and fetal antioxidant capacity. Maternal administration of vitamin C and E was associated with increased fetal cord levels of both vitamins, improved antioxidant status, and enhanced fetal growth in both singleton and twin pregnancies associated with increased placental efficiency. These results highlight the potential of vitamin C and E supplementation to reduce the impact of IUGR in both livestock and humans.