Pathogenesis of congenital infection with Schistosoma japonicum in pigs

To elucidate aspects of pathogenesis of congenital infections with Schistosoma japonicum, 5 Danish crossbred sows were infected during late pregnancy with a Chinese isolate of S. japonicum, and 17 of their offspring (fetuses and piglets) were examined 7, 20. 34, 54, and 69 days postinfection (PI). Organ samples were collected for histopathological examination with emphasis on liver and lung. Samples of the corresponding placenta were also collected from fetuses at postmortem examinations. Perfusions were performed on some of the fetuses to recover schistosomes, and in addition, amniotic fluid was examined for schistosomes. A schistosomulum was found in a 99-day-old fetus 3 wk PI. Eggs were found in meconium from 109-day-old fetuses 34 days after infection of the dam, showing that the prepatent time was the same as in postnatal infections. Piglets examined 54 and 69 days PI had inflammatory reactions in their livers, and progression toward healing and repair of the inflammatory reaction occurred from 54 to 69 days PI. This pilot study is one of the bases for the model of congenital schistosomiasis used currently at the Danish Centre for Experimental Parasitology.     

Transport of steroids between fetuses via amniotic fluid in relation to the intrauterine position phenomenon in rats.

In litter-bearing mammals, the course of development of male and female fetuses is affected by the presence of other fetuses of the same or opposite sex located nearby within the uterus. The transport of testosterone between rat fetuses was examined by implanting a Silastic capsule containing [3H]testosterone into the amniotic sac of a fetus at either the ovarian or cervical end of a uterine horn on days 19 and 20 of pregnancy. The amount of testosterone that was recovered from the amniotic fluid of other fetuses 12 h later was determined. The amniotic fluid surrounding the adjacent fetus on the cervical side of the implanted fetus contained three times as much [3H]testosterone as did the adjacent fetus on the ovarian side, regardless of where in the uterus the implant was made. The movement of dye injected into the uterine lumen was towards the cervix. Intraluminal fluid movement may thus mediate the greater transport of [3H]testosterone towards the cervix than towards the ovary. Our findings support the hypothesis that transport of testosterone between fetuses occurs across the fetal membranes via diffusion, such that any fetus (male or female) located between male fetuses receives the greatest supplement of testosterone.     

Age at puberty, ovulation rate, uterine length, prenatal survival and litter size in Chinese Meishan and Yorkshire females

Studies on the ovulation rate, prenatal survival and litter size of Chinese Meishan pigs have given widely divergent results depending on the extent of inbreeding of the animals, their original genetic diversity, the age and parity, and the conditions of management. To obtain meaningful results, it is necessary to characterize the population under study. The following report characterizes populations of Meishan and Yorkshire of a widely diverse background. First farrowing data were collected on 21 Meishan and 20 Yorkshire gilts. Meishan gilts had 12.4 fully formed piglets and Yorkshire gilts had 7.4 fully formed piglets (P < 0.01). Meishan gilts averaged 1.86 mummified fetuses per litter vs 0.05 per Yorkshire litter (P < 0.01). Yorkshire piglets averaged 1.3 kg body weight at birth vs 0.9 kg for Meishan piglets (P < 0.01). At 47 days of second gestation, 19 Meishan and 12 Yorkshire sows averaged 22.7 and 16.3 corpora lutea (CL), respectively (P < 0.01). Uterine length and number of fetuses were not different (P > 0.40) in the two breeds. Daily estrous detection of 50 Meishan and 34 Yorkshire gilts began at 60 and 120 days of age, respectively. Meishan gilts reached sexual maturity at 95 days of age, which was 105 days earlier than Yorkshire gilts (P < 0.01). Meishan gilts were in estrus nearly 1 day longer than Yorkshire gilts at first, second and third estrus (P < 0.05). No differences in cycle length between breeds were detected for the first or second estrous cycle (P > 0.60). Nineteen Meishan gilts were slaughtered at 51 days of gestation and their reproductive tracts were recovered. The mean number of dissected CL (17.0), number of fetuses (13.1), total uterine length (396 cm), spacing per fetus (29.9 cm), allantoic (124.9 ml) and amniotic (32.2 ml) volumes, crown-rump length (82.8 mm), weight (35.4 g), sex, and direction of each fetus were determined. Chinese Meishan gilts reached puberty much earlier and were in estrus longer than Yorkshire gilts and Meishan sows had more CL than Yorkshire sows.     

Gestational changes in concentrations of selenium and zinc in the porcine fetus and the effects of maternal intake of selenium

The effect of maternal dietary selenium (Se) and gestation on the concentrations of Se and zinc (Zn) in the porcine fetus were determined. Mature gilts were randomly assigned to treatments of either adequate (0.39 ppm Se) or low (0.05 ppm Se) dietary Se. Gilts were bred and fetuses were collected throughout gestation. Concentrations of Se in maternal whole blood and liver decreased during gestation in sows fed the low-Se diet compared to sows fed the Se-supplemented diet. Maternal intake of Se did not affect the concentration of Se in the whole fetus; however, the concentration of Se in fetal liver was decreased in fetuses of sows fed the low-Se diet. Although fetal liver Se decreased in both treatments as gestation progressed, the decrease was greater in liver of fetuses from sows fed the low-Se diet. Dietary Se did not affect concentrations of Zn in maternal whole blood or liver or in the whole fetus and fetal liver. The concentration of Se in fetal liver was lower but the concentration of Zn was greater than in maternal liver when sows were fed the adequate Se diet. These results indicate that maternal intake of Se affects fetal liver Se and newborn piglets have lower liver Se concentrations compared to their dams, regardless of the Se intake of sows during gestation. Thus, the piglet is more susceptible Se deficiency than the sow.     

Effect of partial fetectomy on plasma 13,14-dihydro-15-keto-prostaglandin F2α in late pregnancy of sows

The aim of this study was to ascertain if partial fetectomy in late pregnancy affected prostaglandin F_2α levels, thereby influencing the time of delivery of the remaining fetuses in the sow. Sham fetectomy or surgical removal of one, two, three or four fetal piglets was performed on each of ten sows during the last 3 weeks of pregnancy. Removal of no fetuses (two sows) and in one sow a single fetus was followed by a continuation of pregnancy to the expected time of parturition. Plasma values for oestrone, progesterone and 13,14-dihydro-15-keto-prostaglandin F_2α (PGFM) were similar to those reported previously for normal sows. Removal of one (two sows), two (two sows), three (two sows) or four (one sow) fetuses was followed by premature parturition, within 42–144 h of surgery. Labour lasted 24 to 30 h. Almost immediately after fetectomy, PGFM levels in plasma increased and were accompanied by a decline in progesterone concentrations. High PGFM values (13–60 ng/ml) were present at parturition. Oestrone concentrations were variable or rose slightly at this time. The results suggest that all fetuses in a litter must be present to maintain pregnancy to term. Pregnancy may depend upon fetal suppression of prostaglandin F_2α production and release until the appropriate time for parturition.     

Effect of empty uterine space on birth intervals and fetal and placental development in pigs

A substantial loss of embryos occurs between Days 30 and 40 of pregnancy in the pig under crowded intrauterine conditions, but it is not clear whether this loss affects the growth of adjacent conceptuses. Birth intervals are known to increase with decreasing litter size, but the factors responsible are unknown. Two possibilities are that increased birth weight associated with reduced litter size and the empty uterine space and resulting constricted uterine regions that occur in pigs with small litters may impair piglet delivery. To address these, pregnant gilts were laparotomized on Day 35 of pregnancy and one or two fetuses were manually crushed through the uterine wall on the ovarian or cervical end of each uterine horn to create an empty uterine space behind or in front of the litter of piglets, respectively, in relation to the route of delivery from the uterus. A subset of gilts was slaughtered at 105 days of gestation to confirm that the empty uterine spaces were successfully created and to determine their effects on placental and fetal weights of adjacent conceptuses. At slaughter, the lengths of all externally visible empty constricted regions of the uterus were measured. The uterine horns were opened and the lengths of each placenta were measured from the umbilicus toward the ovary and toward the cervix to assess whether placentas developed symmetrically, and then each fetus and placenta was weighed. Fetal crushing successfully created constricted empty uterine regions on the ovarian and cervical ends of the uterine horns. Ovarian-side placental lengths were greater than cervical-side for conceptuses adjacent to fetuses crushed on the ovarian end of the horn. Cervical-side placental lengths were greater than ovarian-side for conceptuses adjacent to fetuses crushed on the cervical end. Both placental and fetal weights were greater (10% and 6%, respectively, P<0.05) for conceptuses adjacent to crushed fetuses compared to nonadjacent conceptuses. Remaining gilts were farrowed to determine the effect of litter size, average birth weights, and treatment on birth intervals of piglets, which were monitored using 24-h video surveillance. The negative association between number of piglets born alive and average birth interval was confirmed and was not explained by litter size-induced reduction in litter average birth weights. Birth intervals and stillbirth rate did not differ between cervically- and ovarian-treated gilts. These results indicate that conceptus loss on Day 35 of gestation can benefit the growth of adjacent placentas and fetuses, but the benefit is small. Increased average birth weight and the presence of empty uterine space that occurs when litter size is reduced does not fully explain the effect of litter size on birth intervals.     

Short Communication: effect of positive handling of sows on litter performance and pre-weaning piglet mortality

Fear and environmental stressors may negatively affect the welfare of farm animals such as pigs. The present study investigated the effects of music and positive handling on reproductive performance of sows (n = 1014; parity 1 to 8) from a commercial pig farm practicing a batch farrowing system. Every 2 weeks, 56 sows were moved from the gestation unit to conventional-crated farrowing houses 1 week prior to expected farrowing. Treated (T; n = 299) and control (C; n = 715) sows were included in the study. In the farrowing houses, auditory enrichment (music from a radio) was provided to sows of T groups daily from 0600 to 1800 h until the end of lactation. Until the day of farrowing, T sows were additionally subjected, for 15 s per day per sow, to continuous back scratching by one member of farm staff. Litter performance and piglet mortality were recorded and analysed between T and C sows using linear mixed regression models. The number of liveborn piglets (C 13.85 v. T 13.26) and liveborn corrected for fostering (C 13.85 v. T 13.43) was significantly higher (P < 0.05) in C groups compared to the T groups. The number of stillborn piglets was 0.60 and 0.72 in T and C groups, respectively (P > 0.05). With regard to piglet mortality, a linear mixed regression model showed a significant overall effect of treatment in reducing piglet mortality (P < 0.01). Yet, the effect of treatment varied according to litter size (number of liveborn piglets) with a diminishing treatment effect in sows with a high litter size (P < 0.01). Pre-weaning survival was improved in the current study by the combined effect of daily back scratching of sows prior to farrowing and providing music to sows and piglets during lactation. Further research is needed to assess the separate effects of both interventions.     

Effect of radiant heat at the birth site in farrowing crates on hypothermia and behaviour in neonatal piglets

It has been documented that floor heating of the farrowing area in loose housed sows improves survival of piglets significantly. However, today, the majority of farrowing pens are designed with crating of sows and slatted floor at the birth site. The aim of this study was to investigate whether providing radiant heat at the birth site to new-born piglets in pens with crated sows reduced hypothermia, time to first milk intake and growth of the piglets during the 1^st week. Second parity Danish Landrace×Yorkshire sows (n=36) were randomly divided into two groups: Control (CG) and heat (HG). In the area behind the sow (zone 1), two radiant heat panels were mounted above the slatted floor in the HG. The farrowings were attended, and the heaters were turned on at birth of first piglet and turned off 12 h after. Birth time, time to leave zone 1, time to first contact with udder and time to first suckling were registered by direct observation. The piglet’s rectal temperature (RT) was measured 15, 30, 60, 120, 180, 240 min after birth and 12, 14 and 24 h after birth of first piglet. Piglets were weighed at birth, 24 and 48 h and 7 days after birth. Data were analysed in a mixed model in SAS. The drop in RT was lower in HG compared with CG (P=0.002), and the RT in HG remained higher than in CG from 30 to 240 min after birth (P<0.05), whereas no difference was found at 12 h after birth of first piglet (P=0.92). Piglets in HG stayed longer in zone 1 than those in CG (P=0.01), whereas time to reach udder (P=0.35) and to first suckling (P=0.56) did not differ. No difference in weight gain was found between piglets in HG and CG at 24 h (P=0.23), 48 h (P=0.28) and 7 days after birth (P=0.44). Birth weight had a positive effect on RT (P<0.001) and reduced time to leave zone 1 (P<0.01), reach udder (P<0.001) and time to first suckling (P<0.001). The results showed that radiant heating behind the sows reduced hypothermia in new-born piglets and indicate that providing heat during the first half hour after birth is important.     

On the effects of the <Emphasis Type="Italic">Fusarium</Emphasis> toxin deoxynivalenol (DON) administered per os or intraperitoneal infusion to sows during days 63 to 70 of gestation

Six pregnant sows of 180.6 ± 5.6 kg were fed either a Fusarium-contaminated (4.42 mg DON and 48.3 μg ZON per kg, DON per os, n = 3) or a control diet (0.15 mg DON and 5 μg ZON/kg) in the period of days 63 and 70 of gestation. On day 63 of gestation, sows fed the control diet were implanted with an intraperitoneal osmotic minipump (delivery rate of 10 μL/h, for 7 days) containing 50 mg pure (98%) DON in 2 ml 50% DMSO (DON ip, n = 3). Frequent plasma samples were taken to estimate the kinetics after oral and ip DON exposure. The intended continuous delivery of DON by the intraperitoneal minipump could not be shown, as there was a plasma peak (C_max) of 4.2–6.4 ng DON/mL either immediately (sow IP-2+3) or 2.5 h (sow IP-1) after implantation of the pump followed by a one-exponential decline with a mean half-time (t_1/2) of 1.75–4.0 h and only negligible DON plasma concentrations after 12 h. Therefore, the DON ip exposure has to be regarded as one single dose 1 week before termination of experiment. The DON per os sows showed a mean basis level (after achieving a steady state) of DON plasma concentration of about 6–8 ng/mL, as also indicated by the plasma DON concentration at the termination of the experiment. On day 70, caesarean section was carried out, the fetuses were killed immediately after birth, and samples of plasma, urine, and bile were taken to analyze the concentration of DON and its metabolite de-epoxy-DON. At necropsy there were no macroscopic lesions observed in any organ of either sows or piglets. Histopathological evaluation of sows liver and spleen revealed no alterations. The proliferation rate of peripheral blood mononuclear cells (PBMC) with or without stimulation was not affected by the kind of DON treatment. The exposure of pregnant sows at mid-gestation (days 63–70, period of organogenesis) to a Fusarium toxin-contaminated diet (4.42 mg DON and 0.048 mg ZON per kg) or pure DON via intraperitoneal osmotic minipump did not cause adverse effects on health, fertility, maintenance of pregnancy, and performance of sows and their fetuses. However, DON was detected in fetus plasma, indicating that this toxin can pass the placental barrier and may cause changes in the proportion of white blood cells (lower monocyte and neutrophil and higher lymphocyte proportion in DON per os fetuses).     

Farrowing rates and litter size following transfer of vitrified porcine embryos into a commercial swine herd

The objective was to determine farrowing rates and litter sizes that could be achieved in a typical farm-to-farm porcine embryo transfer program using vitrified blastocysts that were zona pellucida intact when cryopreserved. The embryos were transferred surgically on-farm into recipient sows that were managed throughout gestation and farrowing under the same conditions as other sows in the herd. Twenty recipient sows (mean parity 2.1) received a total of 568 embryos; seven received 203 embryos derived from donor sows, five received 139 embryos from gilts and eight received a mixture of 161 embryos from sows and 65 from gilts. Sixteen sows (80%) were confirmed pregnant at approximately 35 days gestation, 15 farrowed at full term (farrowing rate 75%). One sow died during gestation (with a total of 18 fetuses in utero). A total of 123 piglets were born (mean, 8.2), of which 115 were born alive (mean, 7.7). Of the 568 embryos transferred to all 20 sows, 21.6% resulted in piglets born and 29.0% survived to produce piglets in sows that farrowed. There were no significant differences in embryo survival among sow, gilt or mixed sow and gilt embryos. The ratio of males to females was 71/52 and the mean birth weight was 1.6 kg (range 0.6-2.6 kg). In conclusion, vitrified zona pellucida intact embryos can be used to transfer genetic material from farm-to-farm with acceptable reproductive performance.     

Factors affecting duration of the expulsive stage of parturition and piglet birth intervals in sows with uncomplicated, spontaneous farrowings

Modern pig farming is still confronted with high perinatal piglet losses which are mainly contributed to factors associated with the progress of piglet expulsion. Therefore the aim of this study was to identify sow- and piglet factors affecting the duration of the expulsive stage of farrowing and piglet birth intervals in spontaneous farrowing sows originating from five different breeds. In total 211 litters were investigated. Breed affected duration of the expulsive stage significantly: the shortest duration was found in Large White x Meishan F2 crossbred litters and the longest duration in Dutch Landrace litters. No effect of parity on the duration of the expulsive stage was found. An increase in littersize (P<0.01), an increase in number of stillborn piglets per litter (P<0.05) and a decrease of gestation length (P<0.05, independently of littersize) all resulted in an increased duration of the expulsive stage of farrowing. A curvilinear relationship between birth interval and rank (relative position in the birth order) of the piglets was found. Besides that, piglet birth intervals increased with an increasing birth weight (P<0.001). Stillborn (P<0.01) and posteriorly presented (P<0.05) piglets were delivered after significantly longer birth intervals than liveborn and anteriorly presented piglets. The results on sow- and piglet factors affecting duration of the expulsive stage and piglet birth intervals obtained in this study contribute to an increased insight into (patho) physiological aspects of perinatal mortality in pigs.     

Sow level risk factors for early piglet mortality and crushing in organic outdoor production

Piglet mortality is a major problem in organic pig production affecting both farm economy and animal welfare. Knowledge is scarce on the risk factors of piglet mortality in Danish commercial organic pig production. The objectives of this study were to evaluate season, litter size, parity, sow body condition and stillborn littermates as risk factors for early piglet mortality and crushing of liveborn piglets from parturition until castration at day 3 to 5 postpartum (pp). The study was conducted over a 1-year period in nine commercial Danish organic pig herds practicing outdoor farrowing all year round. Data included recordings on 3393 farrowings with 50 284 liveborn piglets of which 14.8% died before castration. A subset of the dead piglets were collected and necropsied to identify crushed piglets. The average number of liveborn piglets per litter was 14.8 (SD=3.7) and the average time from parturition until castration was 4.1 (SD=1.7) days. A negative binomial regression analysis was used to model the effect of the predictive variables on the early piglet mortality accounting for different time periods from parturition to castration. An increase in maternal body condition score (BCS) and parity significantly increased the risk of dying between parturition and castration. Early mortality was found to be lowest during spring (March to May) and highest during summer (June to August). Being born into a litter with one or more stillborn littermates increased the risk of early mortality. The risk factors for crushing of piglets were evaluated using a logistic analysis. A significant effect of parity and litter size was found where the odds of at least one piglet in a litter with mortality was diagnosed as crushed increased with increasing parity and litter size. In conclusion, being born during summer (June to August), high parity and maternal BCS and stillborn littermates were found to be risk factors for piglet mortality between parturition and castration. In addition, parity and increasing litter size were found to be risk factors for crushing of piglets in litters with mortality.     

Climatic effects on sow fertility and piglet survival under influence of a moderate climate

Although the climate in Germany is moderate, heat stress conditions may occur during summer months. However, it is unknown to what extent sow fertility and piglet survival are affected under moderate climatic conditions in indoor systems. Therefore, this study estimated effects of temperature and temperature–humidity index (THI) on sow fertility and piglet survival under practical husbandry conditions. Temperature and relative humidity were recorded in six piglet-producing farms in Lower Saxony, Germany, from July 2011 to August 2012. Based on that, the THI was calculated. In one farrowing, waiting and servicing unit of each farm two data loggers were installed. Reproductive parameters of 8279 successful inseminations and 10 369 litters including total number of piglets born, liveborn, stillborn and weaned piglets as well as pre-weaning mortality were evaluated. The effects of temperature and THI on reproductive parameters were estimated for varying periods after breeding and before and after farrowing, respectively. Average daily temperature across all units ranged from 15.6°C to 29.0°C, and average THI from 62.4 to 75.1. Season and parity significantly affected total number of piglets born, number of liveborn, stillborn and weaned piglets (P<0.001). The number of piglets born increased with rising temperature and THI in the 1^st week post breeding. Higher temperatures and THI values before farrowing resulted in a reduced number of liveborn piglets. Elevated temperature and THI values after farrowing were associated with a greater number of weaned piglets. The pre-weaning mortality significantly decreased with increasing temperature and THI values after farrowing (P<0.05). In conclusion, temperature and THI affected the reproductive performance of the sows and the survival of the piglets in different ways. While increased climatic values at the time of breeding positively affected the total number of piglets born, increased values at the time of farrowing had negative impacts on the reproductive performance of the sows. Piglets benefited from higher temperature and THI values after farrowing.     

A novel approach to intrauterine viral inoculation of swine using PCV type 2 as a model

Experimentally intrauterine (IU) viral inoculation has been commonly used to circumvent maternal interference with transplacental infection of fetuses and to assess the effect of viral infection on fetal development or reproductive parameters. However, IU inoculation requires surgical procedures such as laparatomy and surgical incision of the uterus. Post-surgical complications, that frequently result in abortion or fetal death, have been a major disadvantage. An animal trial was conducted to evaluate the non-surgical procedure of ultrasound needle-guided transabdominal injection for IU inoculation of porcine circovirus type 2 (PCV2) since this virus has been reported to cause reproductive failure in pigs. Two groups of seven pregnant sows at mid- and late-gestation, respectively, were inoculated with PCV2 using an ultrasound needle-guided technique that delivered PCV2 directly into one of the fluid-filled fetal compartments. The effect of transabdominal in utero virus challenge on fetuses and sows was assessed until term. While five of six sham-inoculated control sows had no or minimal adverse affects from in utero injection, 10 of 14 virus-inoculated sows had dead and/or stillborn piglets and PCV2 infection was evident by polymerase chain reaction and/or immunohistochemistry. These results supported previous field and experimental observations that PCV2 may cause reproductive failure. In conclusion, ultrasound needle-guided transabdominal injection was a safe and efficient method for IU inoculation of virus in pigs.     

The transmission of campylobacter in piggeries; an epidemiological study

The campylobacter infection of 10 sows and their piglets was monitored. These pigs werekept on two multiplier farms. Rectal faeces samples were taken from the sows shortly beforelittering and at different intervals after littering. Swab samples of rectal content were taken fromsix piglets per sow at different intervals after birth. Nine sows were shown to be infected withcampylobacter before litter and all sows after litter, with an average colony count of 4·1in log N g^–1 of faeces. Half of the piglets became infected withcampylobacter during the first week of life and 85%, after four weeks. Two genetic subtypingmethods (ERIC-PCR and RFLP) were used to study the relationships between campylobacterisolates from sows and piglets. A large diversity of campylobacter subtypes was found.Nevertheless, piglets and their mothers often harboured campylobacter isolates with identicalgenetic subtyping profiles, suggesting that piglets become infected via their mothers. However,observed similarities in genetic subtyping profiles between campylobacters isolated on differentfarms made this difficult to prove.     

Supplying sows energy on the expected day of farrowing improves farrowing kinetics and newborn piglet performance in the first 24 h after birth

The farrowing process is one of the most energy-demanding activities for the modern hyperprolific sow. This study evaluated the effects of supply of energy on the expected date of farrowing on the farrowing kinetics and piglets’ performance during the first 24 h after birth. A total of 80 sows were used. The sows and their respective litters were considered as the experimental unit. On the expected day of farrowing, the sows were allocated to one of the following groups: sows that did not have access to feed from farrowing induction until the end of the farrowing process (CON, n = 40); sows fed 500 g of energetic supplement, which consisted of 250 g of the basal lactation diet plus 250 g of cane sugar, 18 h after farrowing induction (SUP, n = 40). The farrowing duration, farrowing assistance, birth interval, number of total born, stillborn and mummified piglets were recorded for each sow. Piglets were weighed individually at birth and 24 h later. The interval from birth to first suckle was evaluated individually for each piglet in 16 randomly selected litters (eight litters per treatment group). Blood glucose concentrations of six sows were measured shortly after expulsion of the first piglet. Farrowing duration, farrowing assistance and stillborn rate tended to be greater (P = 0.06, P = 0.09 and P = 0.07, respectively) in sows from the CON group compared to sows from the SUP group. However, there was no difference (P > 0.05) between the groups for birth interval. Colostrum intake was greater (P < 0.05) for piglets from the SUP group compared to piglets from the CON group. Additionally, BW gain of the piglets suckling the SUP group was greater (P < 0.05) than those suckling the CON group at 24 h after birth. The blood glucose concentrations during the expulsive stage of farrowing were greater (P < 0.05) in the SUP group than for sows from the CON group. In conclusion, supplying modern hyperprolific sows energy on the expected day of farrowing is a valuable nutritional intervention to improve the farrowing kinetics and piglets’ performance in early life.     

Sows exposed to octylphenol in early gestation: No estrogenic effects in male piglets, but increased rate of stillbirth

Octylphenol is an industrial chemical with estrogenic effects both in vitro and in vivo. In this study the effects of short-term intramuscular exposure to 0.1 mg/kg of body weight and 1.0 mg/kg of body weight in early gestation were evaluated in pregnant sows with respect to reproductive parameters in the newborn male piglets, as compared with male piglets from unexposed control sows. The male piglets were examined immediately after birth with respect to the macroscopic appearance of the reproductive organs and testosterone concentration in serum. It was not possible to identify any estrogenic effects in the newborn male piglets. However, in the sows exposed at the highest level of octylphenol, there was an increased number of stillborn piglets and an increased proportion of sows with stillborn piglets in the litter (P < 0.05). This was an unexpected finding which has not been reported previously.     

A novel method for the production of transgenic cloned pigs: electroporation-mediated gene transfer to non-cultured cells and subsequent selection with puromycin

Puromycin N-acetyl transferase gene (pac), of which the gene product catalyzes antibiotic puromycin (an effective inhibitor of protein synthesis), has been widely used as a dominant selection marker in embryonic stem (ES) cell-mediated transgenesis. The present study is the first to report on the usefulness of puromycin for production of enhanced green fluorescent protein (EGFP) transgenic piglets after somatic cell cloning and embryo transfer. Somatic cells isolated from porcine fetuses at 73 days of gestation were immediately electroporated with a transgene (pCAG-EGFPac) carrying both EGFP cDNA and pac. This procedure aims to avoid aging effects thought to be generated during cell culture. The recombinant cells were selected with puromycin at a low concentration (2 microg/ml), cultured for 7 days, and then screened for EGFP expression before somatic cell cloning. The manipulated embryos were transplanted into the oviducts of 14 foster mother sows. Four of the foster sows became pregnant and nine piglets were delivered. Of the nine piglets, eight died shortly after birth and one grew healthy after weaning. Results indicate that puromycin can be used for the selection of recombinant cells from noncultured cells, and moreover, may confer the production of genetically engineered newborns via nuclear transfer techniques in pigs.