Piglet Production Research Articles

Production of piglets with sexed semen employing a non-surgical insemination technique

The aim of the present study was to ascertain whether multiparous sows could successfully be inseminated with sexed semen non-surgically. Spermatozoa were stained with Hoechst 33342 and separated flowcytometrically in X- and Y-chromosome bearing sperm populations employing the Beltsville Sperm Sexing Technology (BSST). After weaning, estrus was induced in sows with PMSG and hCG. Animals were inseminated once per estrus non-surgically with a specially designed catheter into the tip of the uterine horn, employing 50 × 10 6 of either sexed or non-sexed spermatozoa diluted in 2 ml Androhep™. Pregnant sows were allowed to go to term. Mean pregnancy rate from inseminations with unsexed spermatozoa was 54.5% whereas inseminations with sexed spermatozoa resulted in 33.3% pregnant sows. All but one piglet born after insemination with sexed semen were of the predicted sex. The sex of those piglets born after inseminations with non-sexed spermatozoa was 61.1% for male and 38.9% for female sex. It is concluded that non-surgically inseminations with flowcytometrically sexed spermatozoa can be conducted successfully.

Detection of rare Leydig cell hypoplasia in somatic cell cloned male piglets

In this investigation, 22 cloned male piglets were obtained by male fetal fibroblast-cell-derived nuclear transfer. Eighteen of the cloned animals died. The two cell lines did not differ significantly with regard to efficiency of live piglet production. The gross anatomy of the testes of male piglets that died was normal. However, one piglet displayed Leydig cell hypoplasia (LCH). No anatomical defects were detected in the testes of other cloned male piglets. TUNEL analysis of the testis with LCH revealed significant apoptosis in the Leydig cells, while apoptosis was rarely detected in Sertoli cells and spermatogonia. In contrast, testes from the remaining 17 piglets that died appeared normal in size, and their Sertoli and Leydig cell numbers were comparable to those in control piglet testes. Although cloned piglets were derived from fibroblasts obtained from the same fetus, phenotypic instability between cells used for the production of somatic cell cloned piglets suggests that abnormalities in male cloned piglets are caused not by technical problems and/or reprogramming effects, but rather by epigenetically and/or genetically damaged cell-specific effects.

Cross-sectional survey in pig breeding farms in Hesse, Germany: seroprevalence and risk factors of infections with Toxoplasma gondii, Sarcocystis spp. and Neospora caninum in sows

A cross-sectional survey was performed to estimate the prevalences of antibodies to Toxoplasma gondii (ELISA, IFAT), Sarcocystis spp. (ELISA, using S. miescheriana as antigen) and Neospora caninum (ELISA, immunoblotting) in sows from breeding farms in southern Hesse, Germany. A total of 2041 plasma samples of sows from 94 randomly selected farms was examined. Data on farm profiles, husbandry management and sows were collected by a questionnaire and exploratively analysed. For T. gondii the ELISA results agreed well with the results obtained by IFAT (kappa = 0.71). Antibodies to T. gondii were detected by ELISA in 19% of the sows. Sixty-nine percent of the farms had at least one seropositive sow, and a within-farm seroprevalence of ≥50% was observed in 14% of all farms. The prevalence of anti- T. gondii antibodies was positively correlated with the age of sows. The within-herd seroprevalence was significantly higher in farms with reproductive disorders than in those without such problems. On the farm level, the farm type ‘piglet production’ (versus ‘pedigree breeding’ or ‘farrow-to-finish’) was the only risk factor associated with the presence of T. gondii-seropositive sows. Antibodies to Sarcocystis spp. were found in 29% of the sows. Seventy-two percent of the farms harboured at least one seropositive sow, and a within-farm seroprevalence of ≥50% was detected in 23% of all farms. The seroprevalence increased significantly with the age of sows. On the farm level, only the farm type ‘piglet production’ (versus ‘pedigree breeding’) and the replacement of sows by purchasing (versus raising on the own farm) were identified as risk factors for seropositivity. Antibodies to N. caninum were detected in one sow using both the screening ELISA and the confirmatory immunoblotting technique. This may indicate the first natural N. caninum infection in pigs.

Carcass quality and technological and sensory meat quality of once-bred gilts in a seasonal outdoor rearing system

Seasonal application of once-bred gilts for piglet and meat production outdoors could be a worthwhile alternative rearing form to normal commercial production. Compared with growing/finishing pigs, payment for sow carcasses is considerably reduced because of an assumed decrease in meat quality and processing properties. The purpose of this study was to compare maiden and once-bred gilts for carcass quality, and technological and sensory meat quality. The control group of 14 gilts (LW*L and LW*D) was reared indoors and slaughtered unmated at an average live weight of 145 kg. In contrast, 38 once-bred gilts of the same breeds were initially reared like the maiden control, inseminated and then housed outdoors from one month before farrowing until slaughter. Carcass traits, technological meat quality (pH, internal and surface reflectance, water holding capacity, commercial processing yield (total yield) and laboratory processing yield (Napole yield), WB shear force and chemical composition of M. longissimus dorsi were measured. Sensory meat quality (taste panel) of oven-baked M. longissimus dorsi and cured and smoked M. semimembranosus et adductor was investigated. Carcass quality traits such as higher lean meat content and lower backfat thickness were preferable with the once-bred gilts. For technological meat quality characteristics, once-bred gilts had lower thawing loss, Napole yield, dry matter and higher total work of WB shear force and intramuscular fat, compared to maiden gilts. In general, sensory meat quality was comparable between the two groups. In processed meat only, once-bred gilts had higher juiciness and salinity and unfavourable increased stringiness, compared to maiden gilts. Thus, once-bred gilts produce valuable carcasses and are suitable for an outdoor seasonal rearing system.

Effect of extra maternal feed supply in early gestation on sow and piglet performance and production and meat quality of growing/finishing pigs

The influence of differentiated extra maternal feed allowance during early gestation on maternal performance and postnatal development of the progeny from gilts and sows was investigated. Four different feed allowances of the same diet (Control [C], +35% [T35], +70% [T70], +100% [T100]) were assigned to 20 crossbred gilts (Swedish Landrace×Swedish Yorkshire), which continued as sows with the same feed allowance the following parity. The progeny was uniformly raised and slaughtered at a live weight of 110 kg. Additional maternal feed allowance resulted in significantly more weaned piglets per sow but not per gilt. Piglet numbers did not increase from T35 to T70/T100. Piglet birth weight did not increase due to maternal feeding. The intra-litter variation in piglet birth weights was similar between the treatments. Independent of the additional feed allowance, all gilts and sows had similar weights after weaning and had good body condition. The growth rate of progeny from sows was negatively related to maternal feed supply; for progeny from gilts, no clear trend of nutritional influence could be observed. Carcass and technological meat quality was not affected by maternal feeding treatment. Birth weight positively affected later growth performance (daily weight gain), carcass quality (lean meat content, back fat, proportion of muscles in ham/loin), whereas technological meat quality was unaffected.

Method for determination of relative relations between economical values and reproductive traits in production of piglets

Bringing into correlation values that by their nature have no joint measuring unit is complex, but these values have decisive effect on production and demand from the researcher to compare them in methodologically correct way and express them through certain value. Determining the expression of values using same measuring units opens many doors of all kinds of analyses and enables their evaluation and possibility for their combination in regard to investigation and inclusion of potential parameters as achievable values. In business activity, different factors of incoming parameters as variables are present, and expected outgoing result should be, more exactly, better in quality and quantity (in the sense of full use of existing capacities or performing of service). At the same time, complete procedure of methodological processing should, first of all, be simple and, secondly easy applicable as well as economical, more exactly profitable. Whole procedure is presented through orientation procedure of the production control procedure and it is carried out or performed in an objective and easy way using registered elements and parameters reaching the economical efficiency of the piglet production. This is complex methodological effort considering the zoological characteristics of the production line, traits and presence of certain variables as parameters of this production. In this paper, procedure of evaluation of components is presented and explained systematically, taking in consideration specific zoological and technological traits, and they were calculated into valuable measuring expressions and units.

The effects of Sepiolite-SPLF on piglet and heavy pig production

In order to evaluate the effects of Sepiolite for Pig Liquid Feeding (Sepiolite-SPLF) on piglet and heavy pig production, two separate trials have been performed. In the first trial a total of 319 piglets from 32 litters was used. From the 6th day of life piglets belonging to 16 litters received a complementary feed containing Sepiolite-SPLF at 1% (Group B); the remaining piglets were fed a complementary feed without sepiolite addition (group A). At weaning (26 days of life), according to the dietary treatment of the suckling period, 80 piglets were homogeneously allocated to two groups fed up to 30 kg body weight a diet containing or not containing Sepiolite-SPLF at 1% (group B and Group A, respectively). In the second trial 330 barrows of the initial body weight of 60 kg were used. Animals were homogeneously allocated to two groups: a control group traditionally fed a soybean-maize based diet and a sepiolite group in which Sepiolite-SPLF was added at 1% (Group B). Pigs were slaughtered at about 170 kg body weight. In both trials daily weight gain, feed intake and pigs’ health were recorded.Weaned piglets on the sepiolite diet showed a highly significant (P<0.01) reduction of diarrhea score (1.55 vs. 2.03 points). At slaughtering the dietary inclusion of sepiolite resulted in a higher uniformity-degree of pigs as it was demonstrated by a higher (P<0.05) frequency of carcasses in the central class comprised between 133 and 145 kg (52% vs. 35%).

277ENERGY REQUIREMENT DURING DEVELOPMENT TO THE BLASTOCYST STAGE OF PORCINE EMBRYOS PRODUCED IN VITRO

A successful in vitro production (IVP) of porcine blastocysts, which enables piglet production after transfer to recipients, was reported (Kikuchi et al., 2002 Biol. Reprod. 66, 1033–1041). Generally, in the IVP system, both glucose and glutamine as energy sources were included in vitro culture (IVC) medium from Day 2 (Day 0=the day of in vitro fertilization) until Day 6. However, the exact requirement of these substances for the development to the blastocyst stage of IVP embryos has not yet been clarified. The objective of the present study was to evaluate whether these two substances are necessary for embryonic development to the blastocyst stage in culture during the period. Porcine cumulus-oocyte complexes were matured for 46h and fertilized in vitro as reported by Kikuchi et al. (see above). After removal of cumulus cells and spermatozoa, the oocytes were cultured subsequently in NCSU-37 supplemented with pyruvate and lactate (IVC-PyrLac) for 2 days. Then they were cultured until Day 6 in other IVC medium prepared as follows (1–6); Basic IVC medium (BM) was a modified NCSU-37 consisting of 108.7mM NaCl, 4.8mM KCl, 1.7mM CaCl2, 1.2mMKH2PO4, 1.2mM MgSO4, 25.1mM NaHCO3 and 4mgmL−1 fatty acid-free BSA. Then one or more of the following energy sources were supplemented to BM;; (1) 12mM sorbitol (SigmaUltra), 5.55mM glucose (Wako special grade) and 1.0mM glutamine (Sigma) (NCSU-37/Gln+), (2) 19.2mM sorbitol and 1.0mM glutamine (IVC-Sorbitol/Gln+); (3) 19.2mM mannitol (SigmaUltra) and 1.0mM glutamine (IVC-Mannitol/Gln+), (4) 12mM sorbitol and 5.55mM glucose (NCSU-37/Gln−); 5) 19.2mM sorbitol (IVC-Sorbitol/Gln−); and 6) 19.2mM mannitol (IVC-Mannitol/Gln−). The osmolarity of these media was adjusted to 283–285 osmolg−1. All embryos were fixed as whole mounts, stained and evaluated. The rate of blastocysts in NCSU-37/Gln+ (26.8%) was significantly higher (P&amp;lt;0.05; by analysis of variance and Duncan’s multiple range test) than those in IVC-Sorbitol/Gln+, IVC-Mannitol/Gln+ and NCSU-37/Gln− (19.0%, 17.0% and 15.5%, respectively). A remarkable decrease in the rates in IVC-Sorbitol/Gln− and IVC-Mannitol/Gln− (P&amp;lt;0.05; 1.4% and 2.0%, respectively) was observed. The cell numbers of NCSU-37/Gln+, IVC-Sorbitol/Gln+, IVC-Mannitol/Gln+ and NCSU-37/Gln− (55.5, 52.0, 49.6 and 58.7, respectively) had a tendency to be higher than those of IVC-Sorbitol/Gln− and IVC-Mannitol/Gln− (38.0 and 35.2, respectively). These results confirm that the supplementation of maturation medium with at least one energy source (glucose or glutamine) promotes embryonic development in vitro to the blastocyst stage, that the combination of both sources improves the chance of the embryonic survival, and that porcine embryos do not utilize sorbitol or mannitol as an energy source. The importance of glucose and glutamine is suggested for the development to the blastocyst stage of porcine IVP embryos.

Production of piglets derived from in vitro-produced blastocysts fertilized and cultured in chemically defined media: effects of theophylline, adenosine, and cysteine during in vitro fertilization.

To further develop defined conditions for in vitro fertilization (IVF) and in vitro culture (IVC) of in vitro-matured porcine oocytes, we evaluated the effects of theophylline, adenosine, and cysteine in a chemically defined medium during IVF. Viability to full term of in vitro-produced blastocysts after IVF and IVC in chemically defined medium was also investigated by embryo transfer to recipients. A chemically defined medium, porcine gamate medium (PGM), was modified from porcine zygote medium (PZM-4), which was previously established. PGM was used as a basal medium for IVF and PZM-4 was for the culture of presumptive zygotes. Addition of 2.5 mM theophylline to PGM significantly increased the percentage of male pronuclear formation compared with controls (no addition). Addition of 1 microM adenosine to PGM supplemented either with or without 2.5 mM theophylline significantly reduced the number of penetrated spermatozoa compared with controls (no addition of adenosine). Supplementation with 0.2 microM cysteine in PGM containing both 2.5 mM theophylline and 1 microM adenosine further increased the percentage of development to the blastocyst stage, compared with no supplementation of cysteine, but there was no difference in fertilization parameters, such as monospermy and pronuclear formation, regardless of presence or absence of theophylline and adenosine. When Day 5 blastocysts were transferred into four recipients (20-25 blastocysts per recipient), all recipients became pregnant and farrowed a total of 21 live piglets. The present results clearly demonstrate that porcine blastocysts can be produced by IVF and IVC in chemically defined media and that they can develop to full term after embryo transfer.

Population biology studies on Isospora suis in piglets.

Isospora suis may cause disease and economic loss in intensive piglet production units. Field studies have shown that litter mates develop varying severeness of isosporosis although initial infection pressure is considered to be identical in a particular farrowing pen. Experimental studies were conducted to evaluate the course of isosporosis under controlled clinical conditions. Piglets artificially infected at the age of 3 days each with 104 sporulated I. suis oocysts suffered from diarrhea from 2 days post infection (dpi) until 9 dpi while oocyst excretion lasted from 6 to 13 dpi. A lower infection dose (1×103 oocysts) resulted in onset of diarrhea at 6 dpi with a prolonged period of disease (10 days) and of oocyst excretion (4-16 dpi). The application of only 100 oocysts within 24 hours after birth caused severe disease starting at 7 dpi. Clinical isosporosis lasted for 6 days and oocysts were excreted from 5 to 14 dpi. Infection at an age of 11 days induced mild diarrhea for a maximum period of 2 days and only few oocysts were detected at 4 to 6 dpi, in one piglet from 7 to 9 dpi. It is concluded that the course of isosporosis is less related to the infective dose than to the age of the piglets. Artificial infection of 30 % of a litter with 1x103 oocysts per piglet at the age of 3 days resulted in rapid spread of isosporosis across the whole litter. However, oocyst excretion and clinical disease was less pronounced on a litter base when only two piglets initially received a low dose of 100 oocysts. Thus, initial contamination of the farrowing pen is obviously related to the course of isosporosis in the respective litter.

Viable piglets generated from porcine oocytes matured in vitro and fertilized by intracytoplasmic sperm head injection.

Intracytoplasmic sperm injection (ICSI) of a nonmotile cell into the ooplasm for assisted fertilization is a highly specialized procedure for producing the next generation. The production of piglets by ICSI has succeeded when in vivo-matured oocytes have been used as recipients. Our objective was to generate viable piglets by using porcine oocytes matured in vitro and fertilized by ICSI after evaluating the efficacy of using donor spermatozoa in which the acrosome had been artificially removed by treatment with calcium ionophore A23187 (Ca-I). The rate of acrosomal loss in spermatozoa was increased significantly as the duration of treatment with 10 micro M Ca-I was prolonged for 30-120 min (Ca-I treated; 55.6-78.6%), whereas the rate was not different as the duration of incubation without Ca-I was prolonged for 30-120 min (control; 45.3-58.4%). On the sixth day of in vitro culture after injection of the sperm head and subsequent stimulation with an electrical pulse, the rates of blastocyst formation were not significantly different between the two groups: the rates for oocytes injected with Ca-I-treated sperm heads (incubated for 120 min) and for those injected with control sperm heads were 8.6% and 4.0%, respectively. The mean cell numbers of the blastocysts were not significantly different between the two groups (25.6 and 22.7, respectively). Within 2 h after the stimulation, the injected oocytes were transferred to estrous-synchronized recipients. The three recipients that received oocytes injected with Ca-I-treated sperm heads (77-150 oocytes per recipient) were not pregnant, whereas two of the four recipients given oocytes injected with control sperm heads (55-100 oocytes per recipient) were pregnant. One of these farrowed three (a male and two female) healthy piglets. The results demonstrate clearly that in vitro-matured oocytes injected with sperm heads are developmentally competent and can produce viable piglets. They also suggest that removal of the acrosome from the spermatozoon before injection does not affect the development of the blastocyst in vitro. This might not also improve the production of piglets in vivo.

Successful production of piglets derived from vitrified morulae and early blastocysts using a microdroplet method

This study was conducted to determine the efficiency of vitrification using the microdroplet (MD) method for early stage porcine embryos. Embryos at compacted morulae to early blastocyst stage were vitrified in a vitrification solution containing 40% (v/v) ethylene glycol, 0.6 M sucrose and 2% (w/v) polyethylene glycol in M2 (ESP) without any pretreatment. The equilibration and dilution were carried out in third and fourth steps, respectively, at 38 °C. The survivability of the cryopreserved embryos was assessed for both in vitro culture (Experiment 1) and by embryo transfer (Experiment 2). In Experiment 1, the embryos were vitrified within a microdroplet or 0.25 ml straw (ST) and fresh embryos were used as a control group. The survival rates after 24 h culture in the MD, ST and control groups were 21/23, 14/20 and 20/20, respectively. The hatching rates of the embryos after 48 h incubation were 14/23, 4/20 and 16/20, respectively. In Experiment 2, 171 vitrified embryos were transferred to 5 recipient gilts, and 17 healthy piglets were produced from 2 recipients (3 recipients aborted) in Group 1. In Group 2, 81 vitrified embryos and 16 fresh embryos in total were transferred to 4 recipient gilts, and 10 healthy piglets from the vitrified embryos were produced from 3 recipients. These results indicated that porcine embryos of compacted morulae to early blastocyst stage can survive cryopreservation using the microdroplet method without any special intracellular manipulation or treatment.

Effect of service sire and validity of repeatability model in litter size and farrowing interval of Finnish Landrace and Large White populations

Data from the Finnish litter-recording scheme were used to find out the effect of service sire on litter size, and to determine whether the assumptions of repeatability model are filled or not in the breeding value estimation of litter size and farrowing interval. Data contained litter records of 6514 Finnish Large White and 9154 Landrace pigs born between 1985 and 2000. Pedigree information was traced back to 1983. (Co)variance components were estimated by the restricted maximum likelihood method using three different statistical models. Variances due to direct animal effects and the service sire, and the covariance between them, were analysed initially using paternal effect model for the first parity litter size records. The same approach was subsequently extended to multiple records per sow by including the permanent environment for dams also. Genetic correlations among different parities were estimated using a multitrait animal model without service sire effects. The effects of model modifications on ranking of selection candidates were studied by comparing pedigree indices of young boars born in 1998 or later. Estimated variance components for both traits were similar across breeds. Heritability estimates ranged between 0.11 and 0.15 for total number of piglets born per litter and between 0.04 and 0.16 for farrowing interval, with estimates being considerably higher within the first two parities than later parities. The proportions of variance due to service sire effect on litter size were extremely low, and the genetic correlation between direct and service sire effects varied around zero. In spite of close correlations of litter sizes across different parities, it appeared that the genetic correlations between the first and later were lower than the correlations between later parities. All genetic correlations for farrowing interval among different parities were lower than one. In conclusion, the first and later parities of litter size, and all the parities of farrowing interval should be treated as separate traits in breeding value estimation. Although the effect of service sire is low, it should still be considered in the statistical model as a random environmental effect to get efficient tool for phenotypic selection of AI boars due to poor piglet production.

Efficient heating of piglet nests

Abstract. The impact of hovers (closed nests) in the farrowing pen on energy consumption was studied. The hovers were equipped with electric heating tube, sensor, and automatically controlled heat regulation. They reduce energy losses and provide a warm environment for piglets, as well as a thermally suitable farrowing unit for sows. Temperature wise, hovers provide a high level of comfort for both. During the two-year experimental period, electricity usage was measured from farrowing to weaning during 60 lactations standardised to 28 days. On average, the electricity consumption was 42.68 kWh per lactation (51.51 kWh in winter and 33.65 kWh during summer season). Major part of the energy was used in the first week of lactation (41.45 %). After that, the weekly usage of energy decreased (29.26 %, 19.89 %, 9.40 % from the second to the fourth week, respectively) because of the decreased needs for supplemental heating and increased self produced warmth of older piglets. The calculation of total costs for heating showed that nearly 100.21 EUR per farrowing pen were saved annually compared to the system without hovers and without heat regulation, a common practice in piglet production.

Production of piglets using intracytoplasmic sperm injection (ICSI) with flowcytometrically sorted boar semen and artificially activated oocytes

The purpose of the present study was to develop a protocol for the successful production of piglets employing intracytoplasmic sperm injection (ICSI) with flowcytometrically sexed spermatozoa and artificially activated porcine oocytes. In vitro matured oocytes were fertilized by ICSI using non-sorted frozen/thawed epididymal semen. Oocytes were either activated by CaCl 2, Ca 2+-ionophore or electrical pulse. Activation and fertilization rates of sperm injected oocytes stimulated by CaCl 2-injection were significantly higher than those without activation (70.4% versus 45.9%; 49.9% versus 33.2%, respectively; P<0.001). Activation rate of sham injected oocytes increased in parallel (11.2% versus 26.3%, P<0.05), parthenogenetic development remained low (2.8% versus 8%). Co-incubation in Ca 2+-ionophore did not improve activation rates as compared to non-activated oocytes (44.8% versus 42.5%). Fertilization rate decreased as compared to non-treated sperm injected oocytes (36.8% versus 24.5%, P<0.05). Activation of oocytes with a single electrical pulse resulted in significantly higher activation rates in all groups of oocytes as compared to non-stimulated ones (sperm injected oocytes: 65.6% versus 43.1%, P<0.001; sham injected oocytes: 48.5% versus 5.6%, P<0.001; control oocytes: 50.7% versus 0.0%, P<0.001). Fertilization rates (32.3% versus 48.2%) and parthenogenetic development (0.7% versus 38.9%, 0.0% versus 30.9%, P<0.001) increased significantly in parallel. In addition, in four replicates of flowcytometrically sorted Y-chromosome bearing spermatozoa were injected into in vivo matured oocytes, activated with 1.2 pl of a 30 mM CaCl 2 solution. On average 85.3 fertilized oocytes were transferred surgically into four recipients. Pregnancies delivered a total of 13 male piglets. These are the first piglets born from ICSI with sorted spermatozoa.

The role of Isospora suis as a pathogen in conventional piglet production in Germany.

In order to evaluate the prevalence of Isospora suis in conventional piglet production in Germany, pooled faecal samples from 327 pig litters from 18 pig production units (20–320 sows each) were examined. At least 10 litters from each farm were investigated. I. suis was present on 83% of the farms and 42.5% of the litters, the infection rate being highest in the third week of age (48.2%). I. suis was found more frequently in samples of diarrhoea than in firm faeces (49.2% compared to 22.2%). Twenty naturally infected piglets from six of these farms underwent examination post mortem, including histology, virology and bacteriology. Histological examination revealed atrophy of the villi in various degrees, mild crypt hyperplasia, fusion of the villi, metaplastic epithelium, erosions and necrosis, especially in the medium and the posterior jejunum and in the ileum. Asexual and sexual developmental stages of the parasite were found in varying numbers in the epithelium of the whole of the small intestine. Bacteria and viruses were mostly excluded as the cause of diarrhoea, and it was concluded that I. suis was the primary pathogen inducing distinct changes and clinical symptoms of diarrhoea.

Successful piglet production after transfer of blastocysts produced by a modified in vitro system.

Porcine in vitro production (IVP) systems, including in vitro maturation (IVM) and in vitro fertilization (IVF) of oocytes and their subsequent in vitro culture (IVC), have been modified by many researchers, but are still at a low level because of a low developmental rate of embryos to the blastocyst stage and their poor qualities. Our objectives were to establish reliable IVP procedures for porcine blastocysts and to examine the ability of the blastocysts to develop to term after transfer to recipients. Porcine cumulus-oocyte complexes were matured in vitro under 5% O(2) or 20% O(2), fertilized in vitro under 5% O(2), and subsequently cultured under 5% O(2) in 1) IVC medium supplemented with glucose (IVC-Glu) from Day 0 (the day of IVF) to Day 6; 2) IVC-Glu from Days 0 to 2, then IVC medium supplemented with pyruvate and lactate (IVC-PyrLac) from Days 2 to 6; 3) IVC-PyrLac from Days 0 to 2, then IVC-Glu from Days 2 to 6; and 4) IVC-PyrLac from Days 0 to 6. There were no significant differences in blastocyst formation rates on Day 6 between the 5% O(2) and 20% O(2) conditions (19.9% and 14.0%, respectively). However, the quality of blastocysts, as evaluated by the total cell number, was better after IVM under 5% O(2) than under 20% O(2) (mean cell number, 43.5 and 37.8, respectively). When IVP embryos were cultured in IVC-PyrLac from Days 0 to 2 and subsequently in IVC-Glu from Days 2 to 6, the rate of blastocyst formation (25.3%) and cell number (48.7) were higher than the rates (5.8% to 18.1%) and numbers (35.4 to 37.1) with the IVC-Glu then IVC-Glu, the IVC-Glu then IVC-PyrLac, and the IVC-PyrLac then IVC-PyrLac regimens, respectively. We then prepared conditioned medium (CM) from culture of porcine oviductal epithelial cells for 2 days in IVC-PyrLac and evaluated its effect on development to the blastocyst stage. Cultivation in CM for the first 2 days, followed by IVC-Glu for a further 4 days, had a significantly greater effect in increasing the number of cells in the blastocyst (58.3) than did in IVC-PyrLac (48.4). Finally, we evaluated the ability of blastocysts, generated by IVM under 5% O(2) and IVC in CM, to develop to term. When Day 5 expanding blastocysts (mean cell number, 49.7) were transferred to an estrus-synchronized recipient (50 blastocysts per recipient), the recipient remained pregnant and farrowed eight normal piglets. Furthermore, when Day 6 expanded blastocysts (mean cell number, 80.2) were transferred to two estrus-synchronized recipients, both gilts remained pregnant and farrowed a total of 11 piglets. These results suggest that an excellent piglet production system can be established by using this modified IVP system, which produces high-quality porcine blastocysts. This system has advantages for the generation of cloned and transgenic pigs.

The effects of clinoptilolite on piglet and heavy pig production

To evaluate the effects of clinoptilolite on piglet and heavy pig production two separated trials have been performed. In the first trial 40 pigs of the initial body weight of 55 kg were used. Animals were homogeneously allocated to two groups: a control group traditionally fed and a clinoptilolite group in which feed contained the additive at 2%. Pigs were slaughtered at about 160 kg body weight. Blood samples were taken to determine blood urea nitrogen (BUN). In the second trial a total of 116 piglets from 12 litters was used. Six litters were fed from the 7th day of life a diet containing clinoptilolite at 2%. According to the dietary treatment of the suckling period, 84 weaned piglets were homogeneously allocated to two groups fed up to 33 kg body weight a diet containing or not clinoptilolite at 2%. In both trials daily weight gain, feed intake and pigs’ health were regularly recorded. The dietary inclusion of clinoptilolite at 2% did not resulted in any modification either of growing performances or of uraemia. Piglets on clinoptilolite diet showed a significant (P<0.05) improvement of faecal dry matter content. At slaughtering the dietary inclusion of clinoptilolite resulted in a trend towards an improvement of lean cuts yield and in a significant increase (P<0.05) of the ratio between lean and fat cuts. From our data it is suggested that clinoptilolite does not impair pig growing performances, determines a higher dry matter content of piglet faeces and improves carcass quality of heavy pigs with particular regard to lean cuts yield and lean to fat cuts ratio.

Influence of the variation of the reproduction cycle period of sows on economical efficiency of piglet production

In this paper, economic efficiency of the piglet production depending on the total annual cost of sow keeping varying per reproduction cycle was investigated. Investigation refers to the determination of the cost of feeding day per live born and reared piglet in conditions of different duration of nonreproductive period in reproduction cycle. Economical efficiency includes good production technology with production result - piglet that enables profit.

A pig with a luminous nose

A litter of transgenic piglets, genetically modified to contain a functional copy of a fluorescent gene found in jellyfish, has been successfully generated by researchers from the University of Missouri, Columbia. The animals all have bright yellow noses and hooves, shown above, a visual indication of successful gene expression. One of the major obstacles to successful transplantation of pig organs to human donors is the likelihood of rejection. It is believed that generation of transgenic pigs would allow specific immune responses to be overcome. The production of these yellow-nosed piglets, published in Animal Biotechnology, is an important demonstration that the technology can work. PoN