Combined synchronization and superovulation treatments negatively impact embryo viability possibly by the downregulation of WNT/β-catenin and Notch signaling genes in the porcine endometrium

The combination of estrus synchronization and superovulation treatments introduces molecular modifications whose effects are yet to be disclosed. Here, reproductive parameters and gene expression changes in ovaries and endometrium were explored on Day 6 after artificial insemination (AI), when synthetic progestin altrenogest (ALT) was combined with gonadotropins. Sows were administered ALT for 7 days beginning on the day of weaning and superovulated with Equine chorionic gonadotropin (eCG) 24 h later and Human chorionic gonadotropins (hCG) at the onset of estrus (SS-7 group; n=6). The controls were either superovulated sows with eCG 24 h postweaning and hCG at the onset of estrus (SC group; n=6) or sows with postweaning spontaneous estrus (NC group; n=6). Ovary examination and embryo and tissue collection were performed in all sows via laparotomy on Day 6 post-AI. RNA-Seq was conducted to analyze differentially expressed genes (DEGs) between groups. Statistical analysis of the reproductive parameters was conducted with an ANOVA and Tukey post hoc tests. DEGs were analyzed with an ANOVA (fold changes ≥2 or ≤2, p value <0.05). Hormonal treatments almost doubled (p<0.03) the number of corpora lutea (39.8±10.2 and 38.3±11.1 in SS-7 and SC sows, respectively) compared with that in the NC group (23.1±3.8). In contrast, embryo viability was significantly decreased (p<0.003) in response to SS-7 treatment (75.1%±15.2%) compared to SC and NC groups (93.8±7.6% and 91.8±6.9%, respectively). RNA-Seq analyses revealed 675 and 1583 DEGs in the SS-7 group compared to both SC and NC groups in endometrial and ovarian samples, respectively. Interestingly, many genes with key roles in the Wnt/β-catenin and Notch signaling pathways were differentially expressed in SS-7 sows relative to SC and NC groups (e.g., Ctnnb1, Myc, Gli3, Scyl2, Ccny, Daam1, Ppm1n, Rbpj, and Usp8). A key finding in this study was the downregulation of β-catenin (Ctnnb1) gene expression in the SS-7 endometrium, suggesting that this treatment influences embryo-uterine dialogue by triggering a cascade of events leading to embryo maldevelopment. These data explain the proliferative defects in SS-7 embryos and suggest a novel mechanism of porcine embryo-maternal crosstalk.

Air pollution and health prevention: A document of reflection

Ambient air quality, pollution and its implication on health is a topic of enormous importance that is normally dealt with by major specialists in their particular areas of interest. In general, it is not discussed from multidisciplinary approaches or with a language that can reach everyone. For this reason, the Health Sciences Foundation, from its prevention area, has formulated a series of questions to people with very varied competences in the area of ambient air quality in order to obtain a global panorama of the problem and its elements of measurement and control. The answers have been produced by specialists in each subject and have been subjected to a general discussion that has allowed conclusions to be reached on each point. The subject was divided into three main blocks: external ambient air, internal ambient air, mainly in the work-place, and hospital ambient air and the consequences of its poor control. Along with the definitions of each area and the indicators of good and bad quality, some necessary solutions have been pointed out. We have tried to know the current legislation on this problem and the competences of the different administrations on it. Despite its enormous importance, ambient air quality and health is not usually a topic of frequent presence in the general media and we have asked about the causes of this. Finally, the paper addresses a series of reflections from the perspective of ethics and very particularly in the light of the events that the present pandemic raises. This work aims to provide objective data and opinions that will enable non-specialists in the field to gain a better understanding of this worrying reality.

Three-to-5-day weaning-to-estrus intervals do not affect neither efficiency of collection nor in vitro developmental ability of in vivo-derived pig zygotes

An efficient system to collect large numbers of vital zygotes is a pre-requisite for application of zygote genome-editing technology, including development of efficient models for xenotransplantation using pigs. Owing to the sub-optimal in vitro production of zygotes in pigs, efficient collection of in vivo developed zygotes is required. Timing of ovulation is a key factor to sustain efficiency since the interval between pronuclear formation and the first division is very short in pigs. The weaning-to-estrus interval can, due to its inverse relation with length of estrus and time of ovulation, interfere with ovulation and make it asynchronous, which reduces the probability of obtaining zygotes. This retrospective study compared the effects of three weaning-to-estrus intervals of 3, 4 or 5 days on zygote collection efficiency in a total of 17 trials over a 3-year period including 223 sows. Donor sows in groups of 10-15 animals were super-ovulated with eCG 24 h after weaning and those in estrus at 48-72 h post-eCG were immediately treated with hCG, followed by insemination 6 and 24 h thereafter. Collected structures during laparotomy on Day 2 (Day 0: onset of estrus) were morphologically evaluated and only those with a single cell and two visible polar bodies were considered as zygotes. Zygotes were injected with CRISPR-Cas9 editor mixture and cultured for 6 days to evaluate their developmental ability against non-injected control zygotes. Of all recovered structures (N = 5,468), 67.4%, 30.8% and 1.8% were zygotes, 2-cell embryos and oocytes-degenerated embryos, respectively. The different weaning-to-estrus intervals did not affect either the percentages of collected zygotes (range: 64.1%-70.0%) or the percentages of sows with zygotes at collection time (range: 69.0%-73.3%). The weaning-to-estrus intervals did not affect the in vitro developmental ability of zygotes. After 24 h of culture, 78.1 ± 2.0% and 95.1 ± 0.6 (P < 0.05) of injected (N = 2,345) and non-injected (N = 335) zygotes, respectively, developed to 2-to-4-cell embryo stage. The total efficiency of the system was 64.1 ± 2.2% and 85.8 ± 1.5% (P < 0.05) for injected and non-injected zygotes, respectively. In conclusion, the results indicate that neither the efficiency of collecting in vivo derived porcine zygotes from superovulated sows nor the zygote ability to develop to blastocyst after cytoplasmic genome-editing injection were affected by a weaning-to-estrus interval between 3-to-5 days.

Social information drives ecological outcomes among competing species

Through its behavior, an organism intentionally or unintentionally produces information. Use of this "social information" by surrounding conspecifics or heterospecifics is a ubiquitous phenomenon that can drive strong correlations in fitness-associated behaviors, such as predator avoidance, enhancing survival within and among competing species. By eliciting indirect positive interactions between competing individuals or species, social information might alter overall competitive outcomes. To test this potential, we present new theory that quantifies the effect of social information, modeled as predator avoidance signals/cues, on the outcomes from intraspecific and interspecific competition. Our analytical and numerical results reveal that social information can rescue populations from extinction and can shift the long-term outcome of competitive interactions from mutual exclusion to coexistence, or vice versa, depending on the relative strengths of intraspecific and interspecific social information and competition. Our findings highlight the importance of social information in determining ecological outcomes.

High pre-freezing sperm dilution improves monospermy without affecting the penetration rate in porcine IVF

The high incidence of polyspermy is still an unresolved problem for the production of in vitro-produced porcine embryos. In this work, we modified the usual sperm processing sequence for in vitro fertilization (IVF), and the spermatozoa from four boars were frozen directly at a low sperm concentration of 20 × 10⁶ sperm/mL (high pre-freezing sperm dilution group; F20), thawed and processed for IVF in three replicates. Spermatozoa from the same boars frozen at a conventional concentration (1000 × 10⁶ sperm/mL) were used as the control group. The post-thaw sperm quality evaluation demonstrated that despite there being no differences in the percentage of motile spermatozoa between groups, the proportion of live spermatozoa with intact acrosomes was significantly higher in the F20 group than in the control. The in vitro penetration rate was also similar between groups; however, the co-incubation of oocytes with F20 sperm increased monospermy, IVF efficiency, cleavage rate and the efficiency of blastocyst formation compared with the results for oocytes co-incubated with control spermatozoa. These results indicate, for the first time, that a high pre-freezing sperm dilution increases monospermy without affecting penetration rates, thereby increasing blastocyst formation.

Importance of oil overlay for production of porcine embryos in vitro

Technologies to edit the zygote genome have revolutionized biomedical research not only for the creation of animal models for the study of human disease but also for the generation of functional human cells and tissues through interspecies blastocyst complementation technology. The pig is the ideal species for these purposes due to its great similarity in anatomy and physiology to humans. Emerging biotechnologies require the use of oocytes and/or embryos of good quality, which might be obtained using in vitro production (IVP) techniques. However, the current porcine embryo IVP systems are still suboptimal and result in low monospermic fertilization and blastocyst formation rates and poor embryo quality. During recent years, intensive investigations have been performed to evaluate the influence of specific compounds on gametes and embryos and to avoid the use of undefined supplements (serum and serum derivate) in the incubation media. However, little consideration has been given to the use of the mineral oil (MO) to overlay incubation droplets, which, albeit being a routine component of the IVP systems, is a totally undefined and thus problematic product for the safety of gametes and embryos. In this review, we provide an overview on the advantages and disadvantages of using MO to cover the incubation media. We also review one important concern in IVP laboratories: the use of oils containing undetected contamination. Finally, we discuss the effects of different types of oils on the in vitro embryo production outcomes and the transfer of compounds from oil into the culture media.

Effects of meiotic inhibitors and gonadotrophins on porcine oocytes in vitro maturation, fertilization and development

This study evaluated the effect of three reversible meiotic inhibitors (MINs) and their interaction with gonadotrophins (Gns) on the meiotic maturation and developmental competence of porcine oocytes. In experiment 1, the oocytes were matured for 22 hr in the presence or absence of dbcAMP (1 mM), cycloheximide (7 μM) or cilostamide (20 μM) with or without Gns, and for an additional 22 hr in the absence of MINs and Gns. At 22 hr of maturation, regardless of the presence of Gns, a higher proportion (p < .001) of oocytes cultured in the presence of MINs were effectively arrested at the germinal vesicle stage compared with the oocytes cultured without MINs. At 44 hr of maturation, the proportion of oocytes that reached MII was higher (p < .05) in groups with Gns compared with groups without Gns. In experiment 2, oocytes that were matured as in experiment 1 were inseminated and cultured for 7 days to evaluate fertilization parameters and blastocyst formation. Only oocytes from the dbcAMP + Gns group had higher (p < .05) efficiency of fertilization compared with the other treatment groups. The presence of dbcAMP during maturation also increased (p < .05) blastocyst formation and efficiency of blastocyst formation in both the presence and absence of Gns. These results indicate that the interaction of Gns with the tested MINs improved meiotic progression. In addition, regardless of supplementation with Gns, the presence of dbcAMP during the first maturation period increased and even doubled the capacity of oocytes to develop to the blastocyst stage.

The Recipients' Parity Does Not Influence Their Reproductive Performance Following Non-Surgical Deep Uterine Porcine Embryo Transfer

With the development of the non-surgical deep uterine (NsDU) embryo transfer (ET) technology, the commercial applicability of ET in pigs is now possible. There are, nevertheless, many factors that influence NsDU-ET effectiveness that need to be addressed. The aim of this study was to evaluate the effects of the weaned recipients' parity on fertility and prolificacy following NsDU-ET. The recipients (n = 120) were selected based on their reproductive history and body condition and grouped into three categories according to their parity: primiparous sows, sows of parity 2 and sows of parities from 3 to 5. Thirty fresh embryos (morulae and unhatched blastocysts) were non-surgically transferred into one uterine horn of each recipient. It was possible to insert the NsDU-ET catheter through the cervix along a uterine horn in 98.3% of the recipients. The parity had no influence on the difficulty grade of the insertions or on the percentage of correct insertions. The cervix and uterine wall were not perforated during the insertions, and vaginal discharge was not observed after transfer in any of the recipients. There were no differences in the pregnancy rates (74.8%), farrowing rates (71.2%) or litter sizes (9.6 ± 3.3) between groups. Also, there were no differences between groups regarding to the piglets' birthweights or piglet production efficiency. In conclusion, these results demonstrate that weaned sows from parity 1 to 5 are appropriate to be used as recipients in NsDU-ET programs, which increase the possibilities for the utilization of ET in the recipient farms.

The effects of superovulation of donor sows on ovarian response and embryo development after nonsurgical deep-uterine embryo transfer

This study aimed to evaluate the effectiveness of superovulation protocols in improving the efficiency of embryo donors for porcine nonsurgical deep-uterine (NsDU) embryo transfer (ET) programs. After weaning (24 hours), purebred Duroc sows (2-6 parity) were treated with 1000 IU (n = 27) or 1500 IU (n = 27) of eCG. Only sows with clear signs of estrus 4 to 72 hours after eCG administration were treated with 750 IU hCG at the onset of estrus. Nonhormonally treated postweaning estrus sows (n = 36) were used as a control. Sows were inseminated and subjected to laparotomy on Days 5 to 6 (Day 0 = onset of estrus). Three sows (11.1%) treated with the highest dosage of eCG presented with polycystic ovaries without signs of ovulation. The remaining sows from nonsuperovulated and superovulated groups were all pregnant, with no differences in fertilization rates among groups. The number of CLs and viable embryos was higher (P < 0.05) in the superovulated groups compared with the controls and increased (P < 0.05) with increasing doses of eCG. There were no differences among groups in the number of oocytes and/or degenerated embryos. The number of transferable embryos (morulae and unhatched blastocysts) obtained in pregnant sows was higher (P < 0.05) in the superovulated groups than in the control group. In all groups, there was a significant correlation between the number of CLs and the number of viable and transferable embryos, but the number of CLs and the number of oocytes and/or degenerated embryos were not correlated. A total of 46 NsDU ETs were performed in nonhormonally treated recipient sows, with embryos (30 embryos per transfer) recovered from the 1000-IU eCG, 1500-IU eCG, and control groups. In total, pregnancy and farrowing rates were 75.1% and 73.2%, respectively, with a litter size of 9.4 ± 0.6 piglets born, of which 8.8 ± 0.5 were born alive. There were no differences for any of the reproductive parameters evaluated among groups. In conclusion, our results demonstrated the efficiency of eCG superovulation treatments in decreasing the donor-to-recipient ratio. Compared with nonsuperovulated sows, the number of transferable embryos was increased in superovulated sows without affecting their quality and in vivo capacity to develop to term after transfer. The results from this study also demonstrate the effectiveness of the NsDU ET procedure used, making possible the commercial use of ET technology by the pig industry.

Non-surgical deep intrauterine transfer of superfine open pulled straw (SOPS)-vitrified porcine embryos: evaluation of critical steps of the procedure

Previous trials achieved extremely poor results when using the one-step warming method in a syringe in combination with non-surgical deep intrauterine transfer (NET) of superfine open pulled straw (SOPS)-vitrified embryos. This study aimed to assess the effect of the warming procedure on the in vitro and in vivo development of SOPS-vitrified embryos. The effect of the passage of the vitrified-warmed (VW) embryos through the NET catheter was also evaluated. Groups of 4 to 6 morulae and blastocysts, collected from weaned sows, were SOPS-vitrified in 1 μL of vitrification medium, warmed by the one-step warming method in a dish or in a 1-mL syringe and cultured in vitro for 48 h to evaluate the embryo survival (ES) and hatching rates (HR). Warming in syringe had a deleterious effect (P < 0.05) on the in vitro ES (60.5 ± 10.4%) and HR (39.6 ± 9.5%) of VW embryos in comparison with embryos warmed in a dish (85.4 ± 10.6% and 69.0 ± 8.4%, respectively). This decreased embryonic development was due to the increased time required between the removal of the straws from the liquid nitrogen and the contact of the embryos with the warming medium when the warming was performed in a syringe in comparison with that for the warming in a dish. After verifying that the passage of VW embryos through the NET catheter does not have a damaging effect on their further in vitro development, the negative effect of warming in a syringe was also confirmed after NET. Fifteen fresh and SOPS-vitrified embryos warmed in a syringe or in a dish were transferred to each recipient (n = 28) and recovered 24 h later to assess their developmental progression. All embryos from the syringe group were found to have degenerated at recovery. The in vivo ES and HR from the dish group (80.4 ± 3.4% and 14.2 ± 7.2%, respectively) were lower (P < 0.05) than those from the fresh group (94.0 ± 4.1% and 36.8 ± 7.8%, respectively). Combining the warming in a dish and the NET procedure, 35 VW embryos were transferred to each of 10 gilts. Five recipients farrowed an average of 10.4 ± 0.9 piglets. In conclusion, the method of one-step warming in a syringe has a negative effect on the in vitro and in vivo viability of SOPS-vitrified porcine embryos. In addition, NET of SOPS-vitrified embryos warmed by the one-step method in a dish showed promising reproductive performance of recipients. However, despite the great potential of this technology, further developments are required for large-scale commercial applications.

Unusual systemic metastases of malignant seminoma in a dog

Unilateral enlargement of left testicle and scrotum was detected in an 8-year-old West Highland White Terrier. The histopathological diagnosis after surgery was a seminoma (SEM) tumour, and a diagnosis of metastatic foci was also detected in vaginal tunic and scrotum. Two months later, new metastatic SEM foci in the skin were diagnosed. Twenty-two months after the initial orchiectomy new multiple cutaneous nodules and a swelling of periesophageal structures were observed. Finally, the necropsy revealed multiple malignant metastatic SEM focus. To the author's knowledge, this is the first description of a canine SEM with unusual widespread metastasis on the base of tongue, soft palate, trachea and pericardium.

Vitrification and warming of in vivo-derived porcine embryos in a chemically defined medium

The aim of this study was to design a protocol for vitrification and warming of porcine embryos in a chemically defined medium. A total of 663 morulae and blastocysts were collected from weaned crossbred sows (Large White-Landrace) 5 to 6 d after estrus and vitrified with the Superfine Open Pulled Straw method. In Experiment 1, embryos were vitrified using as a basic medium TCM-199-HEPES supplemented with 20% newborn calf serum (NBCS) or with 0, 0.1%, 0.5%, or 1% polyvinyl alcohol (PVA). Nonvitrified embryos were used as a fresh control group. Survival and hatching rates were evaluated after 72 h of in vitro culture to assess embryo viability. In addition, some hatched blastocysts derived from morulae and blastocysts were processed to determine the total cell number and the cell proliferating index as measures of their quality. Within each stage of embryo development, the different vitrification groups and the fresh control group showed similar high embryo survival (range, 70.5+/-7.1% to 84.9+/-8.1% and 85.3+/-8.1% to 98.4+/-8.2% for morulae and blastocysts, respectively) and hatching rate (range, 46.3+/-10.1% to 66.7+/-11.2% and 73.7+/-11.3% to 89.4+/-11.2% for morulae and blastocysts, respectively) and quality after in vitro culture. In Experiment 2, embryos were vitrified using 0.1% PVA and warmed with TCM-199-HEPES-0.13 M sucrose supplemented with 20% NBCS or either 0 or 0.1% PVA. Nonvitrified embryos were used as a fresh control group. As in Experiment 1, no significant differences were detected in embryo survival (range, 67.9+/-6.6% to 74.5+/-6.6% and 91.9+/-7.0% to 99.5+/-6.3% for morulae and blastocysts, respectively) and hatching rate (range, 47.0+/-7.2% to 64.8+/-9.9% and 89.4+/-7.4% to 98.2+/-6.9% for morulae and blastocysts, respectively) and quality among the warming groups or among vitrified and fresh control embryos. In both experiments, the developmental embryo stage influenced the survival and hatching rates, as well as the number of cells (P<0.01), with the blastocyst stage yielding the best results. In conclusion, PVA can be used as a substitute for serum in vitrification and warming solutions without detrimental effects on the in vitro development of in vivo-derived porcine morulae and blastocysts.

Pre-pubertal Di(2-ethylhexyl) Phthalate (DEHP) Exposure of Young Boars Did Not Affect SpermIn vitroPenetration Capacity of Homologous Oocytes Post-puberty

Di(2-ethylhexyl) phthalate (DEHP), a plastic softener used in polyvinylchloride (PVC) products (e.g., plastic bags and medical equipment), has been reported to have toxic effects on animal reproduction and is considered an environmental hazard based, mostly, on rodent studies. However, the doses used in these studies are often considerably higher than that presumed in human exposure. In the present study we used young boars as model animals to assess the effects of pre-pubertal DEHP exposure on the ability of spermatozoa to penetrate homologous oocytes in vitro. Eight pairs of cross-bred male boar siblings were used. One brother in each pair became, at random, the test animal exposed to DEHP per os, three times a week, from 3 to 7 weeks of age while the other acted as the control, i.e., placebo-exposed. Semen was collected and frozen between 8 and 9 months of age and stored until spermatozoa were evaluated for their ability to in vitro penetrate in vitro-matured homologous oocytes post-thaw. Both the penetration rate and the number of spermatozoa per oocyte were considered within expected ranges for frozen boar semen of good quality. Penetration rate did not significantly differ (p > 0.05) between the groups with DEHP-exposed: 50%; control: 59%, which could be owing to a large variation between boars, and between replicates. The number of spermatozoa in the ooplasm was low and similar (p > 0.05) between the groups with DEHP-exposed: 1.5 and the control: 1.7. Under the conditions of the present experiment, pre-pubertal exposure to DEHP does not seem to cause a deleterious effect on the in vitro fertilizing ability of frozen spermatozoa post-puberty.

Improving the efficiency of insemination with sex-sorted spermatozoa

The sorting of X- and Y-chromosome-bearing spermatozoa by flow cytometry is nowadays one of the most apt assisted-reproduction technologies in livestock production. Potential economic and biological benefits, as well as those related to easier management of herds, have been reported arising out of the application of this technique, especially in cattle. Yet, the sex-sorting procedure induces damage to spermatozoa, affecting their function and fertilizing ability. Different species present varying degrees of susceptibility to damage from the sorting process and each has its own requirements for sex-sorted insemination procedures. Thus, several new protocols and strategies have been designed for the handling of sorted spermatozoa, with the main objective of optimizing their fertilizing ability and the consequent application of flow-cytometric sex-sorting technology. This article reviews current advances in this technology, pointing out the components to be improved before this technology may be widely applied in different domestic species.

Optimal characteristics of spermatozoa for semen technologies in pigs

Despite the great potential of sperm technologies such as sperm cryopreservation and sperm sex sorting for the improvement of different aspects of swine production, artificial insemination with fresh or stored semen is currently the only sperm technology used at a commercial scale in the pig industry. The lower reproductive performance associated with the use of these sperm technologies is the reason for such limited use. Since optimal characteristics are required for successful application of frozen-thawed and sex-sorted boar spermatozoa, the present paper summarises the value of the current available methods for their functional assessment as well as the effects of these technologies on boar sperm functionality. In addition, strategies developed to reduce sperm damage and improve the yields of both sperm technologies in swine production are also reviewed with particular attention to the contributions of the authors.

In vitro maturation of porcine oocytes with retinoids improves embryonic development

In the present study, the effects of retinoid metabolite administration during in vitro maturation (IVM) on oocyte maturation, parameters of in vitro fertilisation (IVF) and embryo development were examined. Varying concentrations of 9-cis retinoic acid (RA; 0, 5, 50 and 500 nm; Experiment 1) and all-trans retinol (ROH; 0, 125, 1250 and 12 500 nm; Experiment 2) were included in the maturation medium. Cumulus-oocyte complexes were matured in vitro and inseminated with frozen-thawed spermatozoa. Presumptive zygotes were cultured for 16 h to assess IVF parameters or for 7 days to assess embryo development and quality. In Experiment 1, the oocyte maturation rate to metaphase II was significantly decreased (P < 0.001), with values below 5%, in the presence of the highest concentration of RA (500 nm). However, 5 and 50 nm RA had no effect compared with control. Treatment with 5 nm RA improved the blastocyst development rate (P < 0.001). In Experiment 2, the oocyte maturation rate did not differ between 125 and 1250 nm ROH treatment groups and control. However, treatment with 12 500 nm ROH was deleterious because no matured oocytes were observed following the treatment. The penetration rate was lower in the group treated with 1250 nm ROH compared with the 125 nm ROH-treated and control groups, but the blastocyst formation rate did not differ among the three groups. In conclusion, 5 nm RA in the IVM medium significantly increased the blastocyst formation rate, suggesting that RA may play an important role during IVM.

Effects of ultrashort gamete co-incubation time on porcine in vitro fertilization

A reduction in co-incubation time has been suggested as an alternative method to reduce polyspermic fertilization. The aim of this study was to evaluate the effect of short periods of gamete co-incubation during pig in vitro fertilization. A total of 2,833 in vitro matured oocytes were inseminated with thawed spermatozoa and coincubated for 0.25, 1, 2, 3, 7, 10 min and 6h. The oocytes from the 0.25-10 min groups were washed three times in modified Tris-buffered medium (mTBM) medium to remove spermatozoa not bound to the zona and transferred to the same medium (containing no spermatozoa) until 6h of co-incubation time were completed. After 6h, presumptive zygotes from each group were cultured in NCSU-23 medium for 12-15 h to assess fertilization parameters. After each period of co-incubation, 45-50 oocytes from each group were stained with Hoechst-33342 and the number of spermatozoa bound to the zona was counted. Although the number of zona bound spermatozoa increased (p<0.05) with the co-incubation time, no increase was observed in penetration rates among groups from 2 min to 6h of co-incubation time (ranging from 53.5+/-2.8 to 61.3+/-2.6%). Similarly, the efficiency of fertilization reached a maximum for the 2 min of co-incubation group with values ranging between 32.3+/-2.4 and 41.9+/-2.5%. The reduction of co-incubation time did not affect the monospermy rate (range: 71.3+/-3.4-80.2+/-3.8%) and the mean number of spermatozoa/oocyte (range: 1.2+/-0.4-1.4+/-0.5). These results show that, under our in vitro conditions, high penetration rate can be obtained with co-incubation times as short as 2 min, although monospermy could not be improved using this strategy.

Factors affecting the success rate of porcine embryo vitrification by the Open Pulled Straw method

The objectives of this study were: (1) to evaluate the influence of porcine embryo developmental stage on in vitro embryo development after vitrification, (2) to study the efficiency of the one-step dilution procedure, compared with conventional warming, for vitrified embryos at different stages of development, and (3) to determine the influence of the embryo donor on the in vitro survival of vitrified embryos at morulae and blastocyst stages. Two to four cell embryos, morulae and blastocysts were collected by laparotomy from weaned crossbred sows (n=55). Vitrification and conventional warming were performed using the OPS procedure with Superfine Open Pulled Straws (SOPS). For one-step dilution, embryos were placed in 800 microl TCM199-HEPES containing 20% of new born calf serum and 0.13 M sucrose for 5 min. To evaluate development, two to four cell embryos, morulae and blastocysts were cultured in vitro for 120, 48 and 24h, respectively. Some fresh embryos from each developmental stage were not vitrified and cultured as controls. Embryos were morphologically evaluated for their developmental capacity during the in vitro culture by stereomicroscopy. The total cell number of embryos was assessed by Hoechst-33342 staining and fluorescence microscope observation. There was a significant effect of the stage of development on the in vitro survival, perihatching rate and the number of cells of embryos after vitrification and warming (Experiment 1; p<0.001). The survival and perihatching rates of two to four cell embryos were lower than those obtained for morulae and blastocysts (p<0.001). No differences (p>0.05) in survival rates were found between vitrified and fresh blastocysts. The warming procedure did not affect the development and total cell number of vitrified two to four cell embryos, morulae or blastocysts (Experiment 2). However, donor had a significant effect (p<0.001) on the in vitro development and the number of cells of morulae and blastocysts after vitrification and warming (Experiment 3). In conclusion, the embryo developmental stage and the embryo donor were important factors that affected the development of porcine embryos after OPS-vitrification and warming. OPS-vitrification and the one-step dilution are efficient procedures to be used with intact porcine morulae and blastocysts.

Vitrification of in vitro cultured porcine two-to-four cell embryos

The objective of this experiment was to evaluate the effect of a 5-day period of in vitro culture of two-to-four cell porcine embryos up to the blastocyst stage on their ability to survive vitrification and warming. In order to increase the cooling rate, superfine open pulled straws and Vit-Master((R)) technology were used for vitrification. Two-to-four cell embryos were collected from weaned sows (n=11) on day 2 (D0=onset of estrus). Some embryos (N=63) were vitrified within 3h after collection, warmed and cultured for 120h (Group V2). Additionally, 81 two-to-four cell embryos were cultured for 96h in order to obtain blastocysts; these were then vitrified, warmed and cultured for 24h (Group VB; N=65). The remaining two-to-four cell embryos were used as controls and thus not vitrified (control embryos; N=70) but were cultured in vitro for 120h. The V2, VB and control embryos were evaluated for their developmental progression and morphology during culture. All embryos (V2, VB and controls) were fixed on the same day of development in order to assess the total number of blastomeres. The survival and blastocyst formation rates obtained from V2 embryos were very poor (9.6+/-0.7% and 3.2+/-0.5%, respectively). The survival and hatching rates of VB embryos (75.0+/-0.69% and 33.6+/-0.13%) were lower (p<0.001) than those obtained with control embryos (89.1+/-0.8% and 47.5+/-0.12%). Hatched VB embryos had a lower (p<0.01) total cell number than hatched control embryos (70.3+/-4.5 versus 90.6+/-3.2, respectively). There was no difference between expanded VB and control blastocysts. In conclusion, blastocysts derived from in vitro culture of two-to-four cell pig embryos could be successfully vitrified using SOPS straws and Vit-Master.

Brief coincubation of gametes in porcine in vitro fertilization: Role of sperm:oocyte ratio and post-coincubation medium

In this study, a short coincubation time of 10 min was used to determine the effect of different sperm:oocyte ratios during in vitro fertilization (IVF), and different periods of post-coincubation in a medium that is not appropriate for IVF, on fertilization parameters. In the first experiment, a total of 1624 in vitro matured oocytes, from 4 replicates, were inseminated with frozen-thawed spermatozoa at different sperm:oocyte ratios (2000, 1500, 1000 and 500 sperm:oocyte) and coincubated for 10 min or 6 h. The oocytes from 10 min of coincubation were washed in IVF medium to remove spermatozoa not bound to the zona pellucida and transferred to another droplet of the same medium (containing no spermatozoa) for 6h. The oocytes from the other group remained with the spermatozoa for 6h. Oocytes from both groups were then cultured in embryo culture medium (IVC) for 12h to assess fertilization parameters. In the second experiment, 1872 in vitro matured oocytes, in 3 replicates were inseminated with frozen-thawed spermatozoa using the same sperm:oocyte ratios as in the first experiment. The oocytes were coincubated for 10 min and transferred directly to IVC medium for 18 h (group A), to IVF medium (containing no sperm) only for 2h and then to IVC medium for 16 h (group B), or to IVF medium (containing no sperm) for 6h and then to IVC medium for 12 h (group C or control). There was an effect of sperm:oocyte ratio on all fertilization parameters in experiment 1. The efficiency of IVF (number of monospermic oocytes/total number inseminated) was higher (P<0.05) for oocytes coincubated with spermatozoa for 10 min and inseminated with 1500 and 1000 sperm:oocyte (35.8+/-3 and 37.6+/-2.7%, respectively) and for those coincubated for 6h with 500 spermatozoa per oocyte (37.2+/-3.1%). In experiment 2, the penetration and efficiency rates obtained in group A were poor (between 3 and 15%) irrespective of the sperm:oocyte ratio. However, in group B the fertilization parameters were similar to the controls and were also affected by the sperm:oocyte ratio. These results demonstrate that coincubation time may be reduced to 10 min to increase the efficiency of fertilization depending on the sperm:oocyte ratio, and that the spermatozoa bound to the zona pellucida require a maximum of 2h in an appropriate medium to penetrate the oocytes.

Challenges in Pig Artificial Insemination

Semen extended in a liquid state, together with conventional artificial insemination (AI), is the sole sperm technology used by the pig industry. Sperm technologies known for many years, such as cryopreservation, and others developed during recent years, such as sperm sexing, have not yet been integrated into commercial use. Moreover, there has recently been an explosion of new technologies, such as sperm mediated gene transfer or encapsulated spermatozoa which need additional supportive techniques before they can be economically applied to pig breeding. The speed with which the aforementioned sperm technologies are accepted and utilized by the pig industry depends on the availability of efficient insemination procedures. Therefore, AI is entering a new dimension where it will be converted into a tool for the efficient application of current and new sperm technologies. Some new insemination procedures have been recently developed. This review examines the suitability of available insemination procedures for the efficient application of current, emergent and future sperm technology to the pig industry.

Bloodstream cells phenotypically identical to human mesenchymal bone marrow stem cells circulate in large amounts under the influence of acute large skin damage: new evidence for their use in regenerative medicine

OBJECTIVES

Recent work has shown that human bone marrow contains mesenchymal stem cells (MSCs). However, little is known about their presence in peripheral blood. Since these cells are potentially responsible for tissue repair after injury, their number should be increased during these situations. To demonstrate their number during these situations, we measured MSCs in the peripheral blood of healthy donors and burn patients.

MATERIALS AND METHODS

Blood samples were obtained from 15 acute burn patients and 15 healthy donors. We performed flow cytometric analysis, using a large monoclonal antibody panel: CD44, CD45, CD14, DR, CD34, CD19, CD13, CD29, CD105, CD1a, CD90, CD38, CD25. MSC phenotype was considered positive for CD44, CD13, CD29, CD90, and CD105, and negative for the other monoclonals. The testing was performed on day 3 after injury. We correlated the results with the age, sex, and size and type of burns.

RESULTS

Cells expressing the MSC phenotype were detected in the peripheral blood of both groups. Noteworthy, compared with samples from healthy donors (0.0078 +/- 0.0044), blood obtained from burn patients showed a higher MSC percentage (0.1643 +/- 0.115; P < .001). The percentage of MSCs correlated with the size and severity of the burn. Increased values were also observed among younger patients.

CONCLUSIONS

MSCs have an important role in regenerative processes of human tissues. We found cells phenotypically identical to MSCs circulating in physiological number in normal subjects, but in significantly higher amounts during acute large burns. Therefore, they may represent a previously unrecognized circulatory component to the process of skin regeneration.

Adjustments in IVF system for individual boars: value of additives and time of sperm-oocyte co-incubation

In vitro fertilization (IVF) in pigs is still considered sub-optimal, due to the variable occurrence of polyspermy, variability mainly related to sperm differences. The present study was conducted in an attempt to increase the efficiency of the in vitro production of porcine embryos by optimizing the in vitro fertilization (IVF) protocol for individual males, with regard to the composition of the fertilization medium (experiments 1 and 2) and the length of gamete co-incubation time (experiment 3). A total of 5,943 COC's were in vitro matured (IVM) and inseminated with frozen-thawed spermatozoa from 2 boars (A and B). Experiment 1 determined the effect of additives caffeine (2mM), hyaluronic acid (HA; [0.5mg/mL]) and adenosine (10 microM), alone or in combination, to the IVF-medium during sperm-oocyte co-incubation. Experiment 2 tested the addition of various HA (0, 0.5, 1.0 and 1.5mg/ml) and adenosine (0, 10, 20 and 40 microM) concentrations in the fertilization medium; while experiment 3 investigated the effect of two periods of sperm-oocyte co-incubation (10 min or 6h). In the case of 10 min sperm-oocyte co-incubation, oocytes with attaching spermatozoa were further cultured in IVF-medium containing no spermatozoa until the 6h of insemination was completed. Presumptive zygotes were cultured in embryo culture medium for 12-15 h to assess fertilization parameters. In experiment 1, only caffeine significantly influenced the outcome of fertilization, albeit being a clearly boar-dependent effect. In experiment 2, similar boar differences were seen for HA supplementation while presence of exogenous adenosine did not influence fertilization parameters in either boar. The results of experiment 3 demonstrated that a short co-incubation time significantly (P<0.001) increased penetration rate and mean number of spermatozoa per oocyte (74.9+/-3.9% versus 62.7+/-3.9% and 1.5+/-3.2 versus 1.3+/-3.5 for 10 min or 6h, respectively), but reduced mono-spermy (P<0.001, 57.9+/-2.5% versus 70.0+/-2.8%) when boar A was used. However, such effects were not seen with boar B, in which sperm-oocyte co-incubation time did not affect the efficiency of fertilization. In view of the present results, a preliminary screening for each individual male is required to select optimal conditions for IVF.

Incidence of Unilateral Fertilizations after Low Dose Deep Intrauterine Insemination in Spontaneously Ovulating Sows under Field Conditions

A new procedure for non-surgical deep intrauterine insemination (DUI) in unrestrained sows hormonally induced to ovulate, has been reported. In comparison with standard artificial insemination (AI), with this procedure, the sperm numbers inseminated can be reduced 20-fold without reducing the reproductive performance of these hormonally treated sows. The present study evaluated, using two experiments, the reproductive performance applying 20-fold different sperm numbers per AI dose using DUI or standard AI in spontaneously ovulating sows, under field conditions. In experiment 1, AI was applied to crossbred sows at 12, 24 and 36 h after onset of spontaneous oestrus using one of the following two regimes: (i) DUI (treatment) with 0.15 x 10(9) fresh boar spermatozoa in 5 ml of Beltsville thawing solution (BTS) extender (n = 95), and (ii) standard cervical AI (control) with 2.85 x 10(9) fresh spermatozoa in 95 ml of BTS extender (n = 95). The farrowing rates of the two groups of sows were statistically similar (NS). However, a decrease (p < 0.002) in litter size and the total number of pigs born alive was observed in sows inseminated with the DUI procedure. In experiment 2, 42 post-weaned oestrus sows were inseminated following the same design described for experiment 1 during spontaneous oestrus. On day 6 after onset of oestrus, the proximal segment of the uterine horns of the sows were flushed under surgery to retrieve eventual embryos and evaluate the success of fertilization per cornua (e.g. occurrence of effective uni- vs bilateral sperm transport rendering uni- or bilateral, complete or partial fertilization). Retrieved embryos were assessed for cleavage and number of accessory spermatozoa. Although identical overall pregnancy rates were achieved in both insemination groups, the percentage of sows with partial bilateral fertilization and unilateral fertilization was markedly higher (p < 0.05) in the DUI group (35%) compared with the control (standard AI) group (5%), with a consequent lower (p < 0.001) percentage of viable early embryos after DUI. The number of accessory spermatozoa in the zona pellucida of the embryos was highly variable, but higher (p < 0.001) in control animals than in DUI-AI. No accessory spermatozoa were found in oocytes retrieved from sows depicting unilateral fertilization. In conclusion, DUI in spontaneously ovulating sows with 0.15 x 10(9) spermatozoa renders similar farrowing rates but a lower litter size compared with use of standard AI with a 20-fold higher sperm dose. The lower litter size ought to be related to a decreased distribution of spermatozoa after DUI leading to a higher incidence of partial bilateral and unilateral fertilization.

Human mesenchymal stem cells are tolerized by mice and improve skin and spinal cord injuries

INTRODUCTION

We sought to use human mesenchymal stem cells (HMSC) for skin and spinal cord repair in mice.

MATERIALS AND METHODS

Human bone marrow obtained from a young healthy donor was used to separate and culture human mesenchymal stem cells (HMSC). Ten mice were included in each of four groups. A full-thickness skin defect was surgically performed on all mice in groups 1 and 2. A transverse complete medullar section was performed in groups 3 and 4. Groups 1 and 3 received HMSC IV infusion and local HMSC polymer implant. Groups 2 and 4 received only the IV HMSC infusion. Five control animals from each group went through the same lesions but they didn't receive treatment.

RESULTS

After local administration of HMSC into the fibrin polymer combined with the IV infusion of HMSC, there was no immune rejection; all skin defects healed without scar or retraction at a median time of 14 days. Sixty percent of the animals treated with IV infusion and polymer with HMSC simultaneously had improved neurological activities, while all control mice with spinal cord injury experiments died or perpetuated their paralysis with worsening muscular atrophy and increasing propensity to skin damage.

CONCLUSIONS

HMSC are not immunologically reactive and can trespass species defense barriers. Animals treated with these cells repaired injuries better than controls. In this way we propose that universal HMSC from donors can be cultured, expanded, and cryopreserved to be used in human organ or tissue regeneration.

An update on Reproductive Technologies with Potential Short-Term Application in Pig Production

Over the past decade, there has been an increase in the development and/or in the improvement of emerging reproductive technologies in pigs. Among emerging reproductive technologies with potential short-term application in pig production are: artificial insemination with low number of spermatozoa, cryopreservation of spermatozoa and embryos, sperm sexing, and non-surgical embryo transfer. The following review will give emphasis to recent advancements in these reproductive technologies that are starting to show possibilities of serious applications under field conditions.

Does multivariate analysis of post-thaw sperm characteristics accurately estimate in vitro fertility of boar individual ejaculates?

The objective of this study was to determine if a multivariate pattern analysis of frozen-thawed sperm characteristics of boar semen of unknown fertility, thus identifying groups of ejaculates as "good" or "bad" freezers, would estimate their fertilizing potential in an in vitro embryo production (IVP) system. Frozen-thawed spermatozoa from a single ejaculate collected from 46 boars were evaluated for sperm motility and kinematic patterns, for sperm viability and for early changes in sperm membrane stability. All data generated were used for a multivariate pattern analysis (PATN; CSIRO, Canberra, Australia) which objectively classified all ejaculates within a data set in to one of two groups, categorised as "good" (n = 25) or "bad" (n = 21) according with their freezability. In vitro matured oocytes were exposed to 2000 or 4000 frozen-thawed spermatozoa per oocyte for 6h and then cultured in embryo culture medium for either 6h (assurance of fertilization) or 7 days (to collect data on embryo development). Rates of sperm oocyte penetration and of embryo development significantly (p < 0.05) increased in a sperm:oocyte ratio-dependent manner. A similar pattern was observed when sperm characteristics were grouped. Indeed, ejaculates classified as "good" showed significantly (p < 0.05) higher rates of oocyte penetration, cleavage and of blastocyst formation than those classified as "bad". However, variation was still present among individuals (ejaculates, boars) in their ability to produce blastocysts in vitro. It is therefore concluded that despite the presence of a relationship for ejaculates with good semen quality post-thaw (thus grouped as "good") to higher IVP-results, the presence of individual variation does not allow for an accurate estimation of in vitro fertility based solely on the frozen-thawed semen quality parameters of a single ejaculate from a given boar.

Hoechst 33342 stain and u.v. laser exposure do not induce genotoxic effects in flow-sorted boar spermatozoa

Sex selection by flow cytometry/cell sorting involves the staining of spermatozoa with Hoechst 33342 in combination with the impact of a u.v. laser beam, two potentially mutagenic agents. A phenotypic and cytogenetic study of lymphocytes of piglets born after insemination with spermatozoa stained with Hoechst 33342 and from piglets obtained from stain-sorted spermatozoa was performed to evaluate the genotoxic effect of Hoechst 33342 staining and u.v. laser irradiation on the offspring. Lymphocytes from piglets born after insemination with unstained spermatozoa, but from the same ejaculate, were used as a control group. Peripheral blood lymphocytes from these piglets were cultured following a standard cell culture protocol. Cells were then collected by centrifugation, subjected to hypotonic solution and fixed and dropped onto slides. Sister chromatid exchanges (SCEs) and chromosome aberrations (CAs: including chromosome and chromatid breaks) per cell were scored in 50-s division metaphase spreads from each donor. Reproductive parameters and litter performance of all inseminations performed were also recorded in all groups. Data were analyzed by ANOVA. No significant increase (P> 0.05) of SCE and CA frequencies were observed in piglets born from stained spermatozoa or from stain-sorted spermatozoa with respect to controls (untreated sperm). The results indicated that no mutagenic effect on spermatozoa, expressed as increases in the incidence of abnormalities in the resulting offspring and also as increases in SCE and CA frequencies on lymphocytes from these individuals, was induced by the staining of boar spermatozoa with Hoechst 33342, nor by combination of staining with laser impact during flow cytometry.

In vitro development following one-step dilution of OPS-vitrified porcine blastocysts

The objective of this experiment was to compare the in vitro survival and hatching rates of OPS-vitrified porcine blastocysts obtained after conventional (three-step dilution) or direct (one-step dilution) warming procedures. Expanded blastocysts were collected by laparotomy from weaned crossbred sows (n=7) on Day 6 of the cycle (D0: onset of estrus). Vitrification was performed as described by Berthelot et al. [Cryobiology 41 (2000) 116] using 17% (v/v) ethylene glycol and 17% (v/v) dimethyl-sulfoxide in the second vitrification medium. Conventional warming was carried out by plunging straws containing embryos in 800 microl of TCM199 Hepes containing 20% new born calf serum (TCM-NBCS) and 0.13 M sucrose for 1 min. Embryos were then transferred to another well with the same medium for 5 min, washed in TCM-NBCS with 0.075 M sucrose for 5 min and transferred to TCM-NBCS for 5 min. In one-step dilution, embryos were placed in 400 microl TCM-NBCS containing 0.13 M sucrose. To evaluate in vitro development, embryos warmed by conventional (n=59) or direct (n=58) procedures were cultured for 96 h. Non-vitrified embryos were used as controls (n=20). No significant (P>0.05) differences were observed in the in vitro development of vitrified and non-vitrified embryos. The survival and hatching rates obtained by three-step dilution (84.8 and 71.2%, respectively) and one-step dilution (86.2 and 74.1%, respectively) procedures were not different (P>0.05). The average diameter of expanded blastocysts from each donor was significantly different (P<0.001) among embryo donors. The embryo diameter or the interactions among the factors evaluated did not affect (P>0.05) the embryo survival and hatching of the vitrified/warmed blastocysts. However, the donor of embryos had a significant effect (P<0.001) on these parameters, confirming previous experiments. This experiment shows that porcine embryo vitrification and one-step dilution are promising procedures to be used under field conditions. However, the good results obtained in vitro must be confirmed also by in vivo experiments.

Vitrification of porcine embryos at various developmental stages using different ultra-rapid cooling procedures

In this study, three different vitrification systems (open pulled straw: OPS; superfine open pulled straw: SOPS; and Vit-Master technology using SOPS: Vit-Master-SOPS) were compared in order to investigate the influence of cooling rate on in vitro development of vitrified/warmed porcine morulae, early blastocysts, or expanded blastocysts. Embryos were obtained surgically on Day 6 of the estrous cycle (D0 = onset of estrus) from weaned crossbred sows, classified and pooled according their developmental stage. A subset of embryos from each developmental stage was cultured to evaluate the in vitro development of fresh embryos; the remaining embryos were randomly allocated to each vitrification system. After vitrification and warming, embryos were cultured in vitro for 96 h in TCM199 with 10% fetal calf serum at 39 degrees C, in 5% CO(2) in humidified air. During the culture period, embryos were morphologically evaluated for their developmental progression. The developmental stage of embryos at collection affected the survival and hatching rates of vitrified/warmed embryos (P < 0.001). The vitrification system or the interaction of vitrification system and developmental stage had no effect on these parameters (P > 0.05). Vitrified expanded blastocysts showed the best development in vitro (P < 0.001), with survival and hatching rates similar to those of fresh expanded blastocysts. The hatching rate of fresh morula or early blastocyst stage embryos was higher than their vitrified counterparts. In conclusion, under our experimental conditions, cooling rates greater than 20,000 degrees C/min, as occurs when SOPS or Vit-Master-SOPS systems are used, do not enhance the efficiency of in vitro development of vitrified porcine embryos.

Influence of follicle size on the penetrability of immature pig oocytes for homologous in vitro penetration assay

In order to improve the performance of homologous in vitro penetration (hIVP) assays using immature oocytes to assess the penetrating ability of boar sperm, the present study was designed to evaluate the influence of oocyte and follicle size on the penetrability of immature pig oocytes obtained from slaughterhouse ovaries. Nonatretic antral follicles were isolated, measured with a computerized image analysis system and grouped according to their diameter: Group 1 (0.40-0.99 mm), Group 2 (1.00-2.19 mm), Group 3 (2.20-2.79 mm), and Group 4 (2.80-6.50 mm). After sperm coincubation and before penetrability evaluation, the immature oocytes were classified into four size categories according to their diameter excluding zona pellucida: <105, 105-109, 110-114, and > or =115 microm. As regards follicle size, the highest viability and penetrability were obtained with oocytes from follicles >2.20 mm (P>0.05). Regarding oocyte size, significant differences (P<0.05) were observed for all parameters evaluated between oocytes with a diameter above or below 110 microm. However, our results revealed that such differences were due to follicle size rather than oocyte diameter, since oocytes with the same diameter but from different follicle size groups showed different penetration rates. With increasing follicle size, the percentage of penetrated oocytes increased (P<0.05). Finally, our results showed that the greater penetrability of immature oocytes from larger follicles is not due to variations in the thickness of the zona pellucida. There were no significant differences in zona pellucida thickness between oocytes from the four follicular size groups. In summary, these results indicate that follicle size directly affects the penetrability of immature pig oocytes used in hIVP.

Motility characteristics and fertilizing capacity of boar spermatozoa stained with Hoechst 33342

Flow cytometry sorting of spermatozoa using fluorescence dye Hoechst 33342 is the only effective sex selection methodology validated in numerous laboratories. This study was carried out to determine the effect of Hoechst 33342 on the motility and fertility of stained boar spermatozoa. Experiment 1 evaluated motility parameters (percentage of motile spermatozoa, velocity, angularity and oscillation) of boar spermatozoa stained with Hoechst 33342 by a computer-aided sperm analysis (CASA) instrument. Spermatozoa (30 million/ml) were divided into five treatment groups and stained during 1 h at 35 degrees C with 9, 18, 27, 60 and 90 microM of H33342. There were no differences in sperm motility patterns nor percentages of motile spermatozoa incubated in the presence of 9, 18 or 27 microM. Percentage of motile spermatozoa and motility parameters decreased significantly (p < 0.05) at 60 microM of Hoechst 33342. Spermatozoa were immotile at concentration of 90 microM. In experiment 2, pregnancy rates, farrowing rates and litter size from sows (n = 275) artificially inseminated (AI) with either Hoechst 33342 stained (27 microM) or unstained (control) spermatozoa were determined. Sows inseminated with stained spermatozoa had no significant lower pregnancy rate (88.33%) as compared with controls (90.32%). Staining neither affected farrowing rates (85.0 vs 87.7%) nor total number of piglets born (10.56 +/- 0.32 vs 10.47 +/- 0.24, stained and controls, respectively). No phenotypical abnormalities were registered among the newborn piglets. The data suggest that incubating spermatozoa with Hoechst 33342 at levels required for X- and Y-bearing chromosome sperm sorting, does not impair sperm viability or their fertility after AI.

Relationship between antral follicle size, oocyte diameters and nuclear maturation of immature oocytes in pigs

We designed the present study to examine the possible relationship between oocyte, antral follicle size and the nuclear heterogeneity of immature pig oocytes, in order to study the heterogeneity of oocyte populations in ovaries obtained from slaughterhouses. Previously, we carried out an initial experiment to determine, by histological analysis, the effectiveness of the macroscopic criteria (MC) used to screen atretic and nonatretic antral follicles. We recovered 239 follicles by mechanical dissection, measured them with a computerized image analysis system, and classified them into five size categories according to their diameter (FD): Group 1 (0.40-0.99 mm), Group 2 (1.00-2.19 mm), Group 3 (2.20-2.79 mm), Group 4 (2.80-3.59 mm) and Group 5 (3.60-6.50 mm). In relation to histological analysis, the results showed that MC is an effective method to select atretic and nonatretic antral follicles from 0.40 to 6.50 mm in diameter (overall accuracy was 80.75%, with sensitivity and specificity rates of 79.33 and 82.20%, respectively). In a second experiment, we recovered 454 nonatretic follicles, then measured and classified them as mentioned above. We removed oocytes individually from follicles and measured their size (oocyte diameter without and with zona pellucida, OD and TOD, respectively). Finally, we evaluated the relationship between OD, FD and nuclear maturation of immature oocytes (germinal vesicles (GV) Stages 0, I, II, III and IV; diakinesis, prophase I, and metaphase I). Overall OD was 101.77 +/- 0.65, 109.19 +/- 0.45, 113.55 +/- 0.50, 116.92 +/- 0.46 and 117.13 +/- 0.47 microm (Groups 1, 2, 3, 4, and 5, respectively). Differences in OD between groups were significant (P < 0.01), although from 2.80 to 6.50 mm follicles, the oocytes were not different in size. There was a certain heterogeneity in OD within each follicular group. Although we observed a certain degree of nuclear variability, regardless of FD or OD, the present study showed a clear progression in GV when FD increased from 0.40 to 6.50 mm. A positive correlation (r2 = 0.4248; P > 0.05) was established mainly between the nuclear stage and oocyte diameter.

Deep intrauterine insemination and embryo transfer in pigs

A new method for non-surgical deep intrauterine catheterization of pigs, without sedation of the sow, is described. Insemination results obtained with this method using fresh spermatozoa demonstrate that, in comparison to conventional artificial insemination (AI) (3 x 10(9) spermatozoa in 80-100 ml), a 20-60-fold reduction in the number of spermatozoa inseminated and at least a 8-10-fold reduction in the dose volume can be used without affecting fertility if spermatozoa are deposited deep (middle or upper) into one of the uterine horns. Results from deep intrauterine insemination with frozen-thawed spermatozoa and flow-sorted spermatozoa are also presented and the effect of deep intrauterine insemination on sperm transport is discussed. In addition, a brief description of the advances made in non-surgical embryo transfer technology is reported.

Minimum number of spermatozoa required for normal fertility after deep intrauterine insemination in non-sedated sows

A fibreoptic endoscope procedure for non-surgical deep intrauterine insemination in non-sedated sows has been reported. However, the endoscope is an expensive and fragile instrument, and is unsuitable for use under field conditions. The aim of this study was to determine the minimum number of spermatozoa required to maintain optimal fertility using a flexible catheter (1.8 m in length, 4 mm in diameter) for deep intrauterine insemination in 2-6 parity non-sedated sows. Crossbred sows were treated with eCG 24 h after weaning and with hCG 72 h later to induce oestrus. Deep intrauterine insemination was performed 36 h after hCG treatment in 117, 126, 60 and 69 sows with 15.0, 5.0, 2.5 or 1.0 x 10(7) spermatozoa in 10 ml, respectively. Weaned sows (n = 147) not treated with hormones and used for standard artificial insemination (AI) (two inseminations per oestrus with 3 x 10(9) spermatozoa in 100 ml) served as controls. The flexible catheter was passed successfully through the cervix into one uterine horn in 95.4% of the sows in an average of 3.7 +/- 0.09 min. Farrowing rates after deep intrauterine insemination with 15 or 5 x 10(7) spermatozoa did not differ from those of the control group (82.9, 76.2 and 83.0%, respectively), but a significant decrease (P < 0.001) was observed in sows inseminated with 2.5 or 1.0 x 10(7) spermatozoa (46.7 and 39.1%, respectively). In contrast, the number of spermatozoa inseminated did not affect prolificacy. Laparotomy revealed that the tip of the flexible catheter reached approximately the anterior third of the uterine horn. Although deep intrauterine insemination was performed in only one uterine horn, the percentages of embryos collected from the tip of both uterine horns 2 days after deep insemination were not significantly different. The results show that in comparison with standard AI, a 20-60-fold reduction in the number of spermatozoa inseminated and an 8-10-fold reduction in the dose volume can be achieved without decreasing fertility when semen is deposited non-surgically into the upper first third of one uterine horn.

Minimum number of spermatozoa required for normal fertility after deep intrauterine insemination in non-sedated sows

A fibreoptic endoscope procedure for non-surgical deep intrauterine insemination in non-sedated sows has been reported. However, the endoscope is an expensive and fragile instrument, and is unsuitable for use under field conditions. The aim of this study was to determine the minimum number of spermatozoa required to maintain optimal fertility using a flexible catheter (1.8 m in length, 4 mm in diameter) for deep intrauterine insemination in 2-6 parity non-sedated sows. Crossbred sows were treated with eCG 24 h after weaning and with hCG 72 h later to induce oestrus. Deep intrauterine insemination was performed 36 h after hCG treatment in 117, 126, 60 and 69 sows with 15.0, 5.0, 2.5 or 1.0 x 10(7) spermatozoa in 10 ml, respectively. Weaned sows (n = 147) not treated with hormones and used for standard artificial insemination (AI) (two inseminations per oestrus with 3 x 10(9) spermatozoa in 100 ml) served as controls. The flexible catheter was passed successfully through the cervix into one uterine horn in 95.4% of the sows in an average of 3.7 +/- 0.09 min. Farrowing rates after deep intrauterine insemination with 15 or 5 x 10(7) spermatozoa did not differ from those of the control group (82.9, 76.2 and 83.0%, respectively), but a significant decrease (P < 0.001) was observed in sows inseminated with 2.5 or 1.0 x 10(7) spermatozoa (46.7 and 39.1%, respectively). In contrast, the number of spermatozoa inseminated did not affect prolificacy. Laparotomy revealed that the tip of the flexible catheter reached approximately the anterior third of the uterine horn. Although deep intrauterine insemination was performed in only one uterine horn, the percentages of embryos collected from the tip of both uterine horns 2 days after deep insemination were not significantly different. The results show that in comparison with standard AI, a 20-60-fold reduction in the number of spermatozoa inseminated and an 8-10-fold reduction in the dose volume can be achieved without decreasing fertility when semen is deposited non-surgically into the upper first third of one uterine horn.

Successful non-surgical deep intrauterine insemination with small numbers of spermatozoa in sows

A 100-fold reduction of the standard dose for artificial insemination in pigs (3 x 10(9) spermatozoa in 80-100 ml fluid) can be used when spermatozoa are deposited surgically next to the uterotubal junction. The present study was performed to develop a technique for non-surgical deep intrauterine insemination in pigs without sedation of the animal. In Expt 1, sows were weaned, treated to induce oestrus and used to evaluate the difficulties involved in the insertion of a flexible fibre optic endoscope through the cervix and along the uterine horn. Deep uterine catheterizations were performed on each sow at 30-40 h after hCG treatment in the crate in which the animal was housed. The endoscope was inserted through an artificial insemination spirette, moved through the cervical canal and propelled forward along one uterine horn until the entire endoscope was inserted. In 30 sows (90.9%) no or minor difficulties were observed during insertion and in these animals the procedure was completed in 4.1 +/- 0.26 min. Insertion of the endoscope through the cervical canal was not possible in only one sow (3.03%). In Expt 2, endoscopic deep intrauterine insemination at 36 h after hCG treatment was performed in 15, 18 and 13 sows with 100, 20 or 5 x 10(7) spermatozoa, respectively, resulting in farrowing rates of 86.6%, 88.9% and 92.3%, respectively; there were no significant differences among groups. Farrowing rates after deep intrauterine inseminations were also not different from those achieved after standard intracervical insemination with 3 x 10(9) spermatozoa (control group: n = 48; 87.5%). Mean litter size (9.41 +/- 0.38 to 10.02 +/- 0.25) was also similar among the different experimental and control groups. In conclusion, endoscopic non-surgical deep intrauterine inseminations can be performed quickly in sows, and normal farrowing rates and litter sizes can be obtained after insemination with a small number of spermatozoa.