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The objective of this study was to investigate the metabolic and osmotic effects of different doses of glycerol or a glycerol - propylene glycol mixture in Sarda sheep with the aim to identify those able to beneficially modify ewe's metabolic status without harmful changes in red blood cell (RBC) indices. Thereafter, the selected doses were tested for their effects on ewe's ovarian activity during an induced follicular phase and compared to the effects of a hormonal treatment with equine chorionic gonadotrophin (eCG).

The aim of this study was to investigate the blood concentrations of L-arginine, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), and L-homoarginine, which are regulators of nitric oxide (NO) synthesis, in single, twin, and triplet pregnancies in ewes undergoing either a dietary energy restriction or receiving 100% of their energy requirements. From day 24 to 100 of pregnancy, the ewes were fed ryegrass hay and two different iso-proteic concentrates fulfilling either 100% of ewes' energy requirements (control group; n = 30, 14 singleton pregnancies, 12 twin pregnancies, and 4 triplet pregnancies) or only 45% (feed-restricted group; n = 29; 11 singleton pregnancies, 15 twin pregnancies, and 3 triplet pregnancies). Blood samples were collected monthly to measure, by capillary electrophoresis, the circulating concentrations of arginine, ADMA, homoarginine, SDMA, and of other amino acids not involved in NO synthesis to rule out possible direct effects of diet restriction on their concentrations. No differences between groups were observed in the circulating concentrations of most of the amino acids investigated. L-homoarginine increased markedly in both groups during pregnancy (p < 0.001). SDMA (p < 0.01), L-arginine, and ADMA concentrations were higher in feed-restricted ewes than in controls. The L-arginine/ADMA ratio, an indicator of NO production by NOS, decreased towards term without differences between groups. The ADMA/SDMA ratio, an index of the ADMA degrading enzyme activity, was higher in controls than in feed-restricted ewes (p < 0.001). Obtained results show that circulating concentrations of L-arginine, of its metabolites, and the ratio between NO synthesis boosters and inhibitors are altered in energy-restricted ewes, and that these alterations are more marked in ewes carrying multiple fetuses.

The objective of this study was to evaluate whether dairy sheep during the transition period are affected by their parity numbers with regard to (1) body weight (BW), body condition score (BCS), and production performance (milk yield and composition) and (2) metabolic, inflammation, and stress biomarkers. For this purpose, 30 Sarda dairy ewes [15 primiparous (PRP) and 15 multiparous (MUP) ewes] were recruited on d 90 of gestation. Each group was homogeneous according to age, BW, and BCS. Sampling was carried out at −60, −30, −7, 0, +30, and +60 d from lambing. The MUP ewes showed a higher BW (46.32 vs. 38.71 kg) and larger litter size (1.45 vs. 1.06 kg) but a lower BCS (2.47 vs. 2.70) than the PRP ewes. Furthermore, the MUP ewes had lower concentrations of glucose (3.49 vs. 4.27 mol/L), cholesterol (1.63 vs. 1.81 mmol/L), free fatty acids (0.47 vs. 0.62 mmol/L), and triglycerides (0.22 vs. 0.25 mmol/L) compared with PRP ewes. With regard to inflammation and oxidative stress parameters, the PRP group had higher haptoglobin (0.48 vs. 0.18 g/L) and paraoxonase (187.90 vs. 152.11 U/L) activity than the MUP group. Overall, the MUP ewes were characterized by greater milk production performance and greater feed intake, resulting in a better energy balance, than the PRP ewes. Interestingly, these findings highlighted a different metabolic and inflammatory response over the transition period between PRP and MUP ewes, with the latter displaying lower concentrations of inflammatory-related biomarkers.

The present study used a sheep model of intrauterine growth restriction, combining maternal undernutrition and twinning, to determine possible markers of early damage to the fetal kidney. The occurrence of early deviations in fetal hemodynamics which may be indicative of changes in blood perfusion was assessed by Doppler ultrasonography. A total of 24 sheep divided in two groups were fed with the same standard grain-based diet but fulfilling either their daily maintenance requirements for pregnancy (control group; n=12, six singleton and six twin pregnancies) or only the 50% of such quantity (food-restricted group; n=12; four singleton and eight twin pregnancies). All the fetuses were assessed by both B-mode and Doppler ultrasonography at Day 115 of pregnancy. Fetal blood supply was affected by maternal undernutrition, although there were still no evidences of brain-sparing excepting in fetuses at greatest challenge (twins in underfed pregnancies). However, there were early changes in the blood supply to the kidneys of underfed fetuses and underfed twins evidenced decreases in kidney size.

The importance of postnatal pituitary activation as regards female reproductive development is not yet understood. By taking advantage of the experimental model developed in a previous study, i.e. ewe lambs expressing markedly different ovarian phenotypes at 50 days of age, we designed this study to determine whether differences found in ovarian status during the early prepubertal period are due to different patterns of postnatal pituitary activation, and to assess whether these differences have long lasting effects on subsequent reproductive performance. Results showed that ewe lambs with high antral follicle count (AFC) at 50 days of age had significantly lower plasma FSH concentrations and higher anti-Mullerian hormone (AMH) concentrations during the first 9 weeks of age compared with low AFC ewe lambs (P<0.0001).With a longitudinal experiment we showed that a high AFC in the early prepubertal period is associated with consistently higher AMH concentrations and numbers of antral follicles up to the postpubertal period, and with higher pregnancy rates in the first breeding season. In addition, the effect of age in decreasing AMH concentrations was more marked in the low AFC group. Results of the present study demonstrate that ewe lambs undergo different patterns of postnatal pituitary activation. A high AFC at 50 days of age indicates an advanced phase of ovarian maturation, which was accompanied by constantly higher AMH concentrations up to the postpubertal period, a greater ovarian response to FSH stimulation and by higher pregnancy rates at first mating, as compared with the low AFC group. © 2016 Society for Reproduction and Fertility.

Background: The aim of this research was to study the effectiveness of perfusion of intact ovine ovaries with different rates of perfusion and time-period elapsed between extraction of these ovaries and the beginning of perfusion. Methods: Ovaries were perfused through the arteria ovarica (ovarian arteries) with culture medium supplemented with 5% bovine calf serum, 6% dimethyl sulfoxide, 6% ethylene glycol, 0.15M sucrose, Indian ink, and 100 IU/mL heparin at room temperature (22 degrees C). In the first cycle of experiments, ovaries (n = 96) were perfused for 60 minutes just after extraction of ovaries at the following rates of perfusion (mL/hour): 150, 100, 75, 50, 25, 12.5, and 6.3. In the second cycle of experiments, ovaries (n = 26) were perfused at a rate of 25 mL/hour for 60 minutes after extraction of ovaries and their storage at room temperature for 2, 3, 4, and 5 hours, for groups 1, 2, 3, and, 4, respectively. Successful perfusion of blood vessels was detected visible by a blue coloration of the ovarian tissues. Results: The first cycle of experiments showed that the optimal perfusion rates were 50 mL/hour and 25 mL/hour. In the second cycle of experiments, good perfusion of ovaries was established at a perfusion rate of 25 mL/hour for the ovaries of groups when 2 and 3 hours had elapsed after extraction. Conclusions: Effective perfusion of ovine intact ovaries with vascular pedicle was established using freezing medium at room temperature at the rate of perfusion of 25 mL/hour or 50 mL/hour. The ovaries must be perfused not later than 3 hours after the death of animals.

The importance of postnatal pituitary activation as regards female reproductive development is not yet understood. By taking advantage of the experimental model developed in a previous study, i.e. ewe lambs expressing markedly different ovarian phenotypes at 50 days of age, we designed this study to determine whether differences found in ovarian status during the early prepubertal period are due to different patterns of postnatal pituitary activation, and to assess whether these differences have long lasting effects on subsequent reproductive performance. Results showed that ewe lambs with high antral follicle count (AFC) at 50 days of age had significantly lower plasma FSH concentrations and higher anti-Mullerian hormone (AMH) concentrations during the first 9 weeks of age compared with low AFC ewe lambs (P<0.0001).With a longitudinal experiment we showed that a high AFC in the early prepubertal period is associated with consistently higher AMH concentrations and numbers of antral follicles up to the postpubertal period, and with higher pregnancy rates in the first breeding season. In addition, the effect of age in decreasing AMH concentrations was more marked in the low AFC group. Results of the present study demonstrate that ewe lambs undergo different patterns of postnatal pituitary activation. A high AFC at 50 days of age indicates an advanced phase of ovarian maturation, which was accompanied by constantly higher AMH concentrations up to the postpubertal period, a greater ovarian response to FSH stimulation and by higher pregnancy rates at first mating, as compared with the low AFC group. © 2016 Society for Reproduction and Fertility.

This study tested the nutritional benefit of a supplement offered freely to dairy sheep over a period from 60 days before lambing to 60 days after lambing, at stall and grazing. Thirty Sarda dairy sheep on Day 90 of gestation, homogeneous for age, parity number, bodyweight (BW) and body condition score (BCS), were allocated to one of two groups: control (Ctr) or treated (Cry). Over 120 days, both groups received ryegrass hay and concentrate indoors. After weaning, the ewes also had access to pasture for 6 h/day. Throughout the experimental period, the Cry group had ad libitum access to a cooked molasses licking block. No significant differences were observed between the groups in forage, concentrate and total DM intake. During the experiment, the reduction in BCS in early lactation tended to be slower in the Cry than in Ctr group (Ptrend < 0.09), whereas no significant effects were seen on BW. Lamb performance tended to be improved by Cry in terms of liveweight of litter size per sheep (9.65 vs 8.22 kg for Cry and Ctr, respectively; P < 0.07), whereas no significant effects were observed on milk yield and composition, except for a trend for increased fat content in the Cry versus Ctr group (6.15% vs 5.95%, respectively; P < 0.08). Cry ewes had higher blood cholesterol concentrations than did Ctr ewes (1.96 vs 1.63 mmol/L; P < 0.01). Because there were no differences between feed intake at stall and the estimated total DM intake at stall and during grazing between the two groups, the better performance of the Cry group could be explained by an increase of feed use efficiency at the digestive and/or metabolic level. © CSIRO 2014.

The aim of the present investigation was to test the effectiveness of a method of vitrifying rat embryos at different stages of development (from early morula to expanding blastocyst) in a double vitrification procedure. Wistar rat embryos were vitrified and warmed in super-fine open-pulled straws (SOPS). Before being plunged into liquid nitrogen, the embryos were exposed to 40% ethylene glycol + 0.75 M sucrose in TCM-199 + 20% fetal calf serum (FCS) for 20 s at 38degreeC. Subsequent warming and direct rehydration of the embryos was conducted in culture medium (TCM-199 + 20% FCS) at 38degreeC. Early morula stage (7-10 blastomeres) embryos (n = 358) were vitrified, warmed and cultured in vitro (EM group). Batches of these embryos were then cryopreserved again (revitrified) at the early blastocyst (EB group, n = 87), blastocyst (B group, n = 93) or expanding blastocyst stage (ExpB group, n = 73). After the first (EM group) and repeated (EB, B, and ExpB groups) vitrification procedures, developmental rates of 81, 83, 34 and 76%, respectively were achieved (for EM-EB-ExpB P > 0.1; for EM, EB, ExpB-B P < 0.005). Our data demonstrate the possibility of using the described identical protocol for the SOPS vitrification of rat early morulae, early blastocysts and expanding blastocysts. The low survival rate of blastocysts subjected to double vitrification requires further investigation. © 2003 Elsevier Science Inc. All rights reserved.

This study was designed to test the efficiency of recently developed vitrification technology followed by microscope-free thawing and transfer of sheep embryos. In a first set of experiments, in vivo derived embryos ar the morula to blastocyst stage were frozen in an automated freezer in ethylene glycol, and after thawing and removal of cryoprotectants, were transferred to recipient ewes according to a standard protocol (control group). A second group of embryos were loaded into open-pulled straws (OPS) and plunged into liquid nitrogen after exposure at room temperature to the media 10% glycerol (G) for 5 min, 10% G + 20% ethylene glycol (EG) for 5 min, 25% G + 25% EG for 30 s; or 10% EG + 10% DMSO for 3 min, 20% EG + 20% DMSO + 0.3 M trehalose for 30 s. The OPS were thawed by plunging into tubes containing 0.5 M trehalose. After this rapid thawing, the embryos were directly transferred using OPS as the catheter for the transplantation process. In a second set of experiments, in vivo derived and in vitro produced expanded blastocysts were vitrified in OPS and then transferred as described above. The lambing rates recorded (59% for the conventionally cryopreserved in vivo derived embryos, 56% for the vitrified in vivo derived embryos, and 20% for the vitrified in vitro produced embryos), suggest the suitability of the vitrification technique for the transfer of embryos obtained both in vivo and in vitro. This simple technology gives rise to a high embryo survival rate and will no doubt have applications in rearing sheep or other small ruminants. © 2002 Elsevier Science Inc. All rights reserved.