Embryo Weight Research Articles

The effects of GnRH analogue (buserelin) or hCG (Chorulon) on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs

The objectives of this study were to determine the effect of GnRH analogue (buserelin) or human chorionic gonadotrophin (hCG, Chorulon) treatment on Day 12 of pregnancy on ovarian function, plasma hormone concentrations, conceptus growth and placentation in ewes and ewe lambs. After oestrus synchronization with progestagen sponges and eCG, all the animals were mated with fertile rams. Both ewes and ewe lambs (20 per treatment group) were given either normal saline or 4 μg GnRH or 200 IU hCG on Day 12 post-mating. Pre- and post-treatment plasma hormone concentrations were determined in seven pregnant animals per treatment group in samples collected 1 h before and 0, 2, 4, 6, 8, 24, 48 and 72 h after treatment. Overall mean progesterone concentrations were higher ( P < 0.001) in ewes as compared with ewe lambs in saline-treated controls. GnRH or hCG treatment increased ( P < 0.001) mean plasma progesterone concentrations in both age groups, however, post-treatment concentrations were significantly ( P < 0.05) higher in ewes than in ewe lambs. Oestradiol concentrations were similar in the two control groups. In ewes, but not in ewe lambs, both GnRH and hCG treatments significantly ( P < 0.05) increased the mean oestradiol concentrations above pre-treatment levels. Moreover, post-treatment oestradiol concentrations in GnRH- and hCG-treated animals were significantly ( P < 0.05) higher than those in the saline-treated controls. LH release in response to GnRH treatment was greater ( P < 0.05) in ewes than in ewe lambs, whereas FSH release in ewes was less ( P < 0.05) than that of ewe lambs. The effects of GnRH or hCG on conceptus growth and placentation was determined at slaughter on Day 25. In ewes, GnRH treatment increased ( P < 0.05) luteal weight, amniotic sac width and length, and crown-rump length compared with controls, but had no effect on these parameters in ewe lambs. In ewes, hCG treatment also enhanced ( P < 0.05) luteal weight, amniotic sac width and length, crown-rump length, embryo weight and number of placentomes as compared with controls. In ewe lambs, there was no difference ( P < 0.05) between hCG and control groups in luteal weight, embryo weight and amniotic sac width but crown-rump length, amniotic sac length and the number of placentomes forming the placenta were greater ( P < 0.05). In conclusion, GnRH or hCG treatment on Day 12 of pregnancy can increase ovarian function, conceptus growth and placental attachment in ewes. However, these treatments were less effective in ewe lambs.

Reproductive traits in gilts housed individually or in groups during the first thirty days of gestation

Objectives: To compare pregnancy rate and number of embryos 30 days post mating in gilts group-housed in pens of three and gilts housed individually in gestation stalls. Other potential indicators of swine welfare examined included body weight, backfat thickness, lesions, lameness, display of stereotypies, and serum cortisol concentrations. Methods: After artificial insemination, Yorkshire × Landrace gilts were placed in gestation stalls (n = 14) or pens of three gilts each (n = 14 pens, 42 gilts) until 30 days post mating. Measures of welfare and performance assessed before mating and days 1, 3, 7, 14, and 28 post mating were compared between treatment groups. Gilts were euthanized and reproductive tracts were examined on day 30. Results: Group-housed gilts gained more body weight than gilts housed in stalls, but backfat thickness was similar between treatments. The proportion of gilts exhibiting stereotypies on day 28 was not affected by treatment. Lesion scores (0 to 5; 5 = severe) were higher for group-housed gilts and were highest during the first 7 days post mating. On day 30, lameness scores (0 to 5; 5 = severe) were higher in group-housed gilts, and serum cortisol concentration was higher in stall-housed gilts. Pregnancy rate on day 30 was lower for group-housed gilts. The numbers of ovulations and embryos, embryo weight, and crown-rump length were similar between groups. Implications: Indicators of welfare were differentially affected by type of gestation housing, and pregnancy rate was higher in gilts housed individually in stalls.

Differential expression of two GH receptor mRNAs following temperature change in rainbow trout (Oncorhynchus mykiss)

The recent genome duplication in salmonids has led to the presence of two GH receptors (GHRs). As temperature is a determining factor in fish growth, this study aims to determine whether the growth-promoting effect of temperature may be related to a change in GHR gene expression in embryo and juvenile rainbow trout. During embryonic development, using real-time PCR, we showed that high temperatures (12 vs 4 degrees C) increased the amounts of GHR1 transcript up to the hatching stage. By contrast, whatever the stage examined, the levels of GHR2 mRNA were unaffected by the incubation temperature. Nevertheless, incubating eggs with GH led to an enhanced embryo weight only after hatching, suggesting that GHR was not able to mediate the growth-promoting effect of GH before hatching. For juveniles, the GH-binding capacities of fish liver reared at 8, 12 or 16 degrees C revealed that high temperatures led to a lower GH binding. To better understand whether temperature regulates GHR gene expressions independently of nutritional state, fish were reared at 8, 12 or 16 degrees C and either fed ad libitum or with the same ration (1.2% of body weight per day). In the muscle of fish fed ad libitum, a higher rearing temperature increased GHR1 (P<0.001) but not the GHR2 mRNA levels. When the fish were restricted, temperature no longer affected the levels of GHR1 and GHR2 transcript. In the liver of fish fed ad libitum, a higher rearing temperature increased both GHR1 and GHR2 mRNA levels (P<0.001), while in restricted fish, no difference was seen. In conclusion, the two GHR genes are differentially regulated following temperature change and this was related to the period of fish life (embryo or juvenile) and the tissue (liver or muscle). In juveniles, the GHR, by integrating the effect of temperature on plasma GH and nutritional state, could play a key role in the growth-promoting effect of temperature.

Effects of Carbon Source and Explant Type on Somatic Embryogenesis of Four Cacao Genotypes

The effects of five carbon sources (glucose, fructose, maltose, sorbitol, and sucrose) and two explant types (petals and staminodes) on cacao somatic embryogenesis was studied. No growth was observed on both types of explants cultured on sorbitol containing media and slow growth was obtained on media supplemented with maltose. Depending on the genotype, the percentage of explants producing one or more embryos ranged from 6% to 99%, 18% to 98%, and 3% to 82% on media containing glucose, fructose and sucrose respectively. Explants cultured continuously on maltose or sorbitol-containing media failed to produce embryos. Staminode explants produced 3 to 10 times more somatic embryos than petals. A strong genotypic effect on somatic embryogenesis was observed. Staminode explants of the Forastero clones Laranja and PSUSca 6 produced 2 to 30 times more somatic embryos than the Trinitarios UF 613 and ICS 16. During embryo maturation and conversion, no significant differences were observed among glucose, fructose, maltose, or sucrose for embryo weight, total shoot and root production. However, we found that all plantlets produced on glucose had shoots with normal cacao leaves while the other carbon sources sometimes produced plantlets with cotyledon-like leaves.

Injection of Somatic Cell Cytoplasm into Oocytes Before Intracytoplasmic Sperm Injection Impairs Full-Term Development and Increases Placental Weight in Mice1

This study investigated the effects on fertilized embryo development of somatic cytoplasm after its injection into intact mouse oocytes. Mature oocytes collected from female B6D2F1 mice were injected with cumulus cell cytoplasm of different volumes and from different mouse strains (B6D2F1, ICR, and C57BL/6), or with embryonic cytoplasm. After culture for 1 h, B6D2F1 sperm were injected into those oocytes by intracytoplasmic sperm injection (ICSI). The oocytes were examined for pre- and postimplantation developmental competence. Increases in the volume of the somatic cytoplasm from onefold to fourfold resulted in an impairment of blastocyst development and full-term development (28% and 7%, respectively, vs. 96% and 63%, respectively, in the control group; P < 0.01). An increase in the volume of somatic cytoplasm reduced the expression of POU5F1 (more commonly known as OCT4) in expanded blastocysts. The frequency of embryos that developed to the blastocyst stage did not differ when B6D2F1 or ICR somatic cytoplasm was injected, but injection of C57BL/6 somatic cytoplasm induced a two-cell block in embryo development. Injection of the cytoplasm from fertilized embryos did not reduce the frequency of embryos attaining full-term development. Interestingly, somatic cytoplasm significantly increased the placental weight of ICSI embryos, even the injection of onefold cytoplasm (0.20 +/- 0.02 [n = 32] vs. 0.12 +/- 0.02 in the control group [n = 87]; P < 0.01). These findings indicate that the injection of somatic cytoplasm into oocytes before ICSI causes a decrease in preimplantation development, clearly impairs full-term development, and causes placental overgrowth in fertilized embryos. To our knowledge, placental overgrowth phenotypes are only caused by interspecies hybridization and cloning, and in genetically modified mice. Here, we report for the first time that somatic cytoplasm causes abnormal placentas in fertilized embryos. This study suggests that somatic cell cytoplasmic material is one cause of the low rate of full-term development in cloned mammals.

Effect of liquid effluents emitted from phosphatic fertilizer complex in Al-Qaim - Iraq, on some reproductive phenomenon in albino mice

Four groups of albino mice Mus musculus were given drinking water containing 25,50,75 and 100%(v/v) of the liquid effluents for two months , the fifth group were given tap water as a control experiments in order to determine the effect of effluents on some reproductive aspects.The results were as follows : 1- The fertility degree has been significantly decreased as a result of increase in the concentration of polluted water . 2- A significant reduction in the number and weight of embryo, and a significant increase in the percentage of dead embryo for each female has been found with increase in the percentage of polluted water . 3- A significant reduction in the number of births and their weights for each female with increase in the percentage of liquid effluents.

Percent Dry Weight of the Ovule Predicts Peach Seed Viability

Percent Dry Weight of the Ovule Predicts Peach Seed Viability

Effects of Ozone (O3) on Survival and Development of Chick Embryos After Gas Exposure In Ovo

We investigated the embryotoxicity of ozone (O3), after gas exposure in ovo, to chick embryos of the Lohmann‐Weiss strain. The main aim of the study is to reduce the microbiological content, particularly of Salmonella enteritides on the egg surface by the use of ozone in different concentrations and response times. The aim of our morphological study is to analyse the influence of gas exposure to the embryonal development of chick. Ozone has proved its worth as a disinfectant without the harmful adverse effects of formaldehyde. The chick embryo provides a useful and well‐defined model for analysis of toxicity of chemicals, particularly with regard to an alternative disinfectant: ozone. Embryotoxicity of ozone in developing chick embryos was studied by examining different parameters: deformities and pathohistology of heart, liver, kidney and spleen, weight, length and survival of embryo. After oviposition the eggs were transferred to a chamber filled with ozon‐oxygen‐mixture in a defined concentration (1% ‐ 5.22%). After achievement of the ozone concentration the eggs were incubated over various response times have 20, 30, 60 min or 17 h. After the incubator times of 18, 19 or 20 days we studied the development of the gas exposed embryos and unexposed controls. The organs were fixed in 4% formalin, embedded in paraffin, cut and stained with hematoxylin‐eosin. High ozone concentration over 5% and high response time of 1 hour provided low graded survival rates of 3.3–13.3%. There was significantly increase of the survival rate after decline of ozone concentration and response time of 90–100%. We found also a remarkable decrease of weight and length in fewer surviving gas exposed embryos with high ozone concentration and response time (Fig. 1.), compared with the normal development of gas‐exposed embryos with study of high survival rate (Fig. 2.). We calculated a 60% increase in the survival rate of embryos exposed to high ozone concentration without response time. In low ozone concentration (1.8%) with high response time of 17 hours the survival rate decreased to 10%. We found no signs of deformities and pathohistology of organs in our embryological examination. In conclusion, ozone has a dose‐dependent effect. The response time constitutes an important factor in the survival and growth of chick embryos after exposure to ozone in ovo. image [ High ozone concentration over 5% and high response time of 1 hour result in a low survival rate of 3,3% and the surviving embryo shows a decrease in body weight and length (right) in comparison to the biggest (left) and lowest (middle) unexposed embryo. ] image [ Height comparison between the unexposed controls (both embryos on the left side) with gas exposed embryos (both embryos on the right side) in a study with low ozone concentration of 1% and low response time of 20 minutes. There are no differences in body weight and length between the unexposed and exposed embryos. ]

High-frequency plant regeneration through cyclic secondary somatic embryogenesis in black pepper (Piper nigrum L.)

A high-frequency plantlet regeneration protocol was developed for black pepper (Piper nigrum L.) through cyclic secondary somatic embryogenesis. Secondary embryos formed from the radicular end of the primary somatic embryos which were originally derived from micropylar tissues of germinating seeds on growth regulator-free SH medium in the absence of light. The process of secondary embryogenesis continued in a cyclic manner from the root pole of newly formed embryos resulting in clumps of somatic embryos. Strength of the medium and sucrose concentration influenced the process of secondary embryogenesis and fresh weight of somatic embryo clumps. Full-strength SH medium supplemented with 1.5% sucrose produced significantly higher fresh weight and numbers of secondary somatic embryos while 3.0 and 4.5% sucrose in the medium favored further development of proliferated embryos into plantlets. Ontogeny of secondary embryos was established by histological analysis. Secondary embryogenic potential was influenced by the developmental stage of the explanted somatic embryo and stages up to "torpedo" were more suitable. A single-flask system was standardized for proliferation, maturation, germination and conversion of secondary somatic embryos in suspension cultures. The system of cyclic secondary somatic embryogenesis in black pepper described here represents a permanent source of embryogenic material that can be used for genetic manipulations of this crop species.

Embryonic Growth of Chicks under the Influence of Electric Field

Eggs from layer-type breeder flocks (Leghorn and Baladi, King Saud University) between 40 and 45 weeks of age were used in 2 trials to study the effects of electric field (EF) during incubation on embryonic growth and egg water loss. The incubator was divided into two compartments for the control and EF treatments. Two aluminum plates were fitted to the inside walls, face to face, in the EF compartment and connected to a step up electric transformer. The level of the EF was 30 kV/m, 60Hz. Eggs were set in an incubator on trays either in the control or EF during 18 d of incubation. EF incubation increased egg weight loss, and embryonic weight when expressed on an absolute value, percentage of egg weight, and daily weight gain by approximately 14.3, 50, 49.4, and 46.2%, in Leghorn, and 9.6, 14.7, 14.6, and 14.9%, in Baladi eggs, respectively. There were significant interactions between incubation treatment and age of the embryo on egg weight loss and embryo weight. EF incubation had significantly higher percentage of water loss and embryo weight at 16 and 14 d of incubation and older in Leghorn eggs, respectively and at 15 d of incubation and older in Baladi eggs, when compared with their counterparts of the control incubation treatment. It was concluded that the exposure of chicken eggs to EF of 30 kV/m, 60Hz, during incubation increased the egg water loss, and embryonic growth.

Toxic effects of paroxetine on sexual and reproductive functions of rats

This study determined some appropriate parameters to detect male and female reproductive, endocrine, and teratological toxicity besides genotoxic effects of paroxetine. Several parameters concerning fertility were measured in male and female rats given oral doses of paroxetine ( 0.36mg/100g b.wt./day) for a month. In addition, estimation of the drug residues in male, female and fetus were carried out. There were alterations in serum concentration of gonadotraphins: FSH, LH, PRL and in the sex hormones : testosterone, progesterone and estradiol in male and female rats. These alterations were accompanied by sperm reduction, sperm abnormalities, irregular shaped of seminiferous tubules, hypertrophy of geominal cells and structural chromosomal aberrations in male rats. A reduction in mating and fertility indices were observed with an increase in the number of resorbed fetuses, and a decrease in body weight and crown rump length of rat embryos.

Toxic effects of paroxetine on sexual and reproductive functions of rats

This study determined some appropriate parameters to detect male and female reproductive, endocrine, and teratological toxicity besides genotoxic effects of paroxetine. Several parameters concerning fertility were measured in male and female rats given oral doses of paroxetine ( 0.36mg/100g b.wt./day) for a month. In addition, estimation of the drug residues in male, female and fetus were carried out. There were alterations in serum concentration of gonadotraphins: FSH, LH, PRL and in the sex hormones : testosterone, progesterone and estradiol in male and female rats. These alterations were accompanied by sperm reduction, sperm abnormalities, irregular shaped of seminiferous tubules, hypertrophy of geominal cells and structural chromosomal aberrations in male rats. A reduction in mating and fertility indices were observed with an increase in the number of resorbed fetuses, and a decrease in body weight and crown rump length of rat embryos.

Comparison of three lines of broiler breeders differing in ascites susceptibility or growth rate. 1. Relationship between acoustic resonance data and embryonic or hatching parameters

Ascites is a prevalent cardiovascular disease among modern broilers with negative impacts on production and animal welfare. The peak of mortality due to ascites occurs at the end of the growing period, but the etiology of this problem may start during embryonic development. A few recent reports have demonstrated that the signs of ascites susceptibility are manifested during the late stages of incubation. In the current study, we used a nondestructive method based on egg acoustic resonance parameters [resonant frequency (RF) and damping] to establish a relationship between embryo physiological events during early development in broiler eggs and susceptibility to ascites. The hatching eggs of 3 broiler lines differing in ascites susceptibility were used for this study: ascites-resistant dam line (DAR), ascites-sensitive dam line (DAS), and ascites-sensitive sire line (SASL). These lines were selected on the basis of fast growth, high breast meat yield, and ascites induction at low temperatures such that the order of ascites susceptibility in terms of mortality was SASL >> DAS > DAR. Eggs were incubated under standard conditions in forced-draft incubators. We measured egg weights at setting, albumen pH, Haugh units (HU) at setting, and embryo weights at d 11 and 18, at internal pipping (IP), and at hatch. The durations of IP, external pipping (EP), and hatching were also determined. At 2 hourly periods during incubation, egg RF and damping were also measured. There were differences in egg weights between DAR and SASL vs. DAS, but albumen HU, albumen pH, and the ratio of yolk weight to egg weight were similar. There were differences in RF, damping, embryonic growth rates, and hatching events. Changes in resonant frequency and damping, which certainly suggest eggshell differences among lines, were not totally related to variations in physiological events during early and late embryonic development. A comparison between DAR and DAS, between DAS and SASL, or DAR and SASL indicates that sensitivity to ascites and selection for rapid growth rate in ascites-sensitive lines have different effects on embryonic parameters. We concluded that the sensitivity of broiler breeders to ascites does not influence egg internal quality, but the occurrence of ascites sensitivity in broilers could not be reliably predicted by early in ovo acoustic resonance parameters and hatching events.

Effects of Dietary Administration of CL-20 on Japanese QuailCoturnix coturnix japonica

Hexanitrohexaazaisowurtzitane, or CL-20, is an emerging highly energetic compound currently under consideration for military applications. With the anticipated wide use of CL-20, there is the potential for soil and groundwater contamination resulting in adverse toxicologic effects on environmental receptors. Presently, there is a lack of data describing the toxic effects of CL-20 on avian species. The present study describes the effect of CL-20 on Japanese quail (Coturnix coturnix japonica) modified from standard toxicity test guidelines. First, a 14-day subacute assay was adopted using repeated gavage doses (0, 307, 964, 2439, 3475, or 5304 mg CL-20/kg body weight (BW)/d for 5 days followed by no CL-20 exposure (vehicle only) for 10 days. Second, a subchronic feeding assay (0, 11, 114, or 1085 mg CL-20/kg feed) was done for 42 days. During both studies, no overt toxicity was observed in the CL-20-treated birds. During the first 5 days of the subacute study, CL-20-exposed birds showed a dose-dependent decrease in BW gain, whereas increased liver weight, plasma sodium, and creatinine levels were observed in birds receiving the highest dose tested. For the subchronic study, embryo weights were significantly decreased in a dose-dependent manner. Embryos from CL-20-exposed birds were observed to have multiple cranial and facial deformities, beak curvatures, possible mid-brain enlargement, and classic one-sided development with micro-opthalamia (nonstatistical comparisons with control embryos). A trend toward decreased number of eggs laid per female bird was also observed. We conclude that CL-20 (or its degradation products) elicits few effects in adults but may affect avian development, although these preliminary findings should be confirmed.

Effect of intensity of eggshell pigment and illuminated incubation on hatchability of brown eggs

1. The effects of intensity of brown eggshell pigment (light (LBP), medium (MBP) and dark (DBP)) and light intensity during incubation (low and high, 900 to 1380 and 1430 to 2080 lux, respectively) on eggshell characteristics, embryonic growth, hatchability traits, chick hatching weight and hatching time were investigated using eggs from a meat-type breeder (Hybro) flock at 32, 36 and 41 weeks of age in three trials. 2. With eggs of similar weights the intensity of brown pigment was not associated with eggshell weight and thickness, and did not influence embryo weight and egg weight loss during incubation. 3. The shade of brown pigment of eggs laid by young hens influenced the percentage hatchability (HP) of eggs incubated under light. Illuminated incubation improved HP of LBP eggs (compared with MBP and DBP eggs) from 32- and 36-week-old hens, but had no significant effect on HP of eggs from 41-week-old hens. 4. Light intensity during incubation did not influence egg weight loss. High intensity of light during incubation reduced HP and increased early death percentage (EDP) in the LBP and MBP groups, and did not influence HP and EDP in the DBP group. 5. Brown eggshell pigment and intensity of light during incubation did not influence hatching time. 6. It is concluded that the shade of brown pigment, intensity of light during incubation and age of the breeder hens influenced the hatchability performance of embryos from brown eggs. Light during incubation improved the hatchability of embryos in light brown eggs laid by young hens and the shade of brown pigment of eggs laid by older hens did not influence hatchability under illuminated incubation. 7. High intensity of light during incubation reduced hatchability of light and medium brown eggs, but not the dark brown eggs.

Effects of turning duration during incubation on embryo growth, utilization of albumen, and stress regulation

Eggs from Cobb broiler breeders were incubated for 18 d. Eggs were not turned (T0) or were turned until 9 (T9), 12 (T12), 15 (T15), or 18 (T18) d. First, the effects of turning on embryo and albumen weights were studied. Samples of eggs were opened at d 9, 12, 15, and 18 for embryo and albumen weighing. The results show that embryos from unturned eggs had lower weights and higher remaining albumen weights than those from turned eggs. At d 18, albumen utilization was completed in the T12, T15, and T18 groups only. Also, further turning until d 15 and 18 increased embryo weights. The responsiveness of the embryo after adrenocorticotropic hormone (ACTH) injection was studied to test stress control in embryos. Blood samples were collected from embryos at 60 and 150 min after injection at d 12, 15, and 18 and were analyzed for corticosterone concentrations. The results showed that basal corticosterone levels increased with embryo age. At 60 min after ACTH injection, corticosterone levels were lower at d 12 than at d 15 and 18. At 150 min after ACTH injection, corticosterone levels followed different trends according to incubation stage and turning duration. The highest basal corticosterone levels were obtained with the T15 group at d 15 and 18. Also at d 18, corticosterone levels in the T15 group were the highest at 150 min after ACTH injection. We concluded that egg turning was required during incubation until d 12, at least, and should not be stopped until after d 15.

Influence of Precalving Feed Allowance on Periparturient Metabolic and Hormonal Responses and Milk Production in Grazing Dairy Cows

Fifty-two multiparous dairy cows were allocated to 4 treatments consuming 5.4, 8.2, 10.0, or 11.0 kg/d of pasture dry matter per cow for 27±9.6 d precalving. This equated to 1.3, 1.9, 2.4, and 2.6% of body weight (BW; not including the conceptus weight). Following calving, all cows were fed ad libitum on pasture. Blood was sampled 17 d precalving, on day of calving, and on d 1, 2, 3, 4, 7, 14, 28, and 35 postcalving. Results suggest that the near-term grazing dairy cow requires 1.05 MJ of ME/kg of BW0.75 and that previous estimates of energy requirements were underestimated. Precalving plasma concentrations of glucose, insulin-like growth factor-1, and leptin increased quadratically with increasing pasture intake. This was associated with precalving plasma concentrations of growth hormone that declined linearly, and concentrations of nonesterified fatty acids and β-hydroxybutyrate that declined quadratically with increasing dry matter intake (DMI). Postcalving plasma concentrations of these metabolites showed no lasting effect of precalving feeding. The effect of precalving nutrition on milk production was small, and other than milk fat, was confined to wk 1 postcalving. Milk fat yield increased with increasing precalving DMI and calving body condition score until wk 3 post-calving, after which treatment effects were not evident. These results indicate that the level of feeding in grazing dairy cows during the last month before calving has only small effects on cow metabolic and hormonal status, and on milk production in the first 5 wk of lactation.

139 INJECTION OF SOMATIC CELL CYTOPLASM INTO OOCYTES BEFORE ICSI IMPAIRED FULL-TERM DEVELOPMENT AND INCREASED PLACENTA WEIGHT IN MICE

During the process of somatic cell nuclear transfer, cytoplasm is introduced into the enucleated oocytes, in addition to the genomic material, regardless of the electrofusion methods (Wilmut et al. 1997) or direct injection of somatic nucleus by the Honolulu method (Wakayama et al. 1998). Only 1 to 2% of cloned embryos, however, develop to term with many incidences of developmental anomalies. These cloning failures may be explained by incomplete reprogramming of the donor cell genome, although it is not yet clear whether cytoplasmic materials of the somatic cell also have an affect on development of the cloned embryo. In an attempt to answer this question, this study investigates the effects of somatic cytoplasm of different mouse strains and cytoplasm of fertilized embryos at different stage by injecting them into intact mouse oocytes before intracytoplasmic sperm injection (ICSI). Mature oocytes collected from B6D2F1 female after 14 to 16 h of hCG injection were injected with (1) B6D2F1 cumulus cell cytoplasm with different volumes (collected by 2 to 3 �m of injection pipette and piezo pulses), (2) cumulus cell cytoplasm from different mouse strains (B6D2F1, ICR, C57BL/6), (3) cytoplasm of 1- to 8-cell embryos. After subsequent culture for 1 h, B6D2F1 sperm were injected into those oocytes and examined for preimplantation developmental competence. The total number of cells, inner cell mass (ICM), and expression of Oct4 in expanded blastocysts were also examined. In order to examine the effects of somatic cytoplasm on full-term development, we transferred 2-cell embryos at 24 h or morula and blastocysts at 72 h after ICSI to the oviduct or uterus of surrogate mothers (ICR) on Day 1 or 3 of pseudopregnancy. The control group received a sham injection with PVP before ICSI. The results showed that an increase the volume of cytoplasm from 1-fold to 4-fold (equivalent with the volume of 1 cumulus cell) resulted in impairing full-term development (28 and 7%, respectively, vs. 56 to 63% in the control group, P &lt; 0.01). There was no difference in the frequency of embryos developing to the blastocyts stage between B6D2F1 and ICR somatic cytoplasms at the same volume. However, C57BL/6 somatic cytoplasm induced the 2-cell block to B6D2F2 embryos. Fertilized embryo cytoplasm did not reduce the frequency of blastocyst stage and full-term development. Interestingly, we found that somatic cytoplasm increased the placenta weight of ICSI embryo (0.2002 � 0.03, n = 32; vs. 0.1198 � 0.02 in control group, n = 87; P &lt; 0.01). We also obtained placenta with no fetus when the volume of somatic cytoplasm was the same size as cumulus cell. We found that an increase in the volume of somatic cytoplasm led to low expression of Oct4 in expanded blastocysts. These findings indicated that injection of somatic cytoplasm into oocytes before ICSI decreased the preimplantation development, clearly impaired full-term development, and caused placental overgrowth in fertilized embryos. This study suggested that somatic cell cytoplasmic material is one cause of the low rate of full-term development of cloned animals.

Effects of Low-Frequency Magnetic Fields on Different Parameters of Embryo of Gallus Domesticus

The possible impact of magnetic fields on biological entities is an important but highly controversial issue. We studied the body weight, cranial development (external diameters), and brain weight of embryos subjected to magnetic fields of different intensities.Throughout their development, chick embryos were exposed to 50 Hz magnetic fields of 1 μT, 0.5 mT, or 1 mT intensity. The parameters were studied at 15 and 21 days of incubation.At 15 days of incubation, body weight was significantly lower vs. controls in all treated embryos: the transverse cranial diameter was increased vs. controls at all intensities used except for 1 mT; the vertical cranial diameter was greater vs. controls in all embryos exposed to 1 mT, whereas it was smaller in those exposed to 1 μT or 0.5 mT.At 21 days of incubation, the body weight and cranial diameters of treated embryos were all smaller vs. controls, with a significance that depended on the intensity of the magnetic field.There were no differences in brain weight between treated and control embryos, either at 15 or 21 days of incubation.These data support the hypothesis that magnetic fields may affect embryonic development.

Embryonic and fetal development in a commercial dam-line genotype

During depopulation of a breeding unit within Swine Graphics Enterprises, extensive data were collected and used to examine relationships among ovulation rate, the pattern of prenatal loss, and placental and fetal development. Groups of Large White × Landrace females ( n = 447) were slaughtered between day 20–30, 50–55 or 85–90 of gestation, with approximately equal numbers of animals representing gilts and parity 1 (G/P1), parity 2–3 (P2/3), and parity >4 (P4+). Ovulation rate and embryo number were recorded for all animals. With the exception of the G/P1 animals, embryonic and placental weight were recorded for four conceptuses per sow on day 20–30; on day 85–90 two conceptuses per sow were dissected to determine placental and fetal development. Ovulation rate (22.7 ± 0.2 overall) was higher ( P < 0.05) in P2/3 (23.6 ± 0.4) and P4+ (24.7 ± 0.4) than in G/P1 (20.2 ± 0.5). Embryonic/fetal survival was 61.8 ± 2.1% at day 20–30, 50.2 ± 2.2% at day 50–55 and 48.7 ± 1.9% at day 85–90 and the number of surviving conceptuses was higher ( P < 0.05) in the P2/3 sows than in other parity groups. There was no relationship between ovulation rate and number of live embryos at day 20–30 or 85–90. At day 20–30 and 85–90, embryo weight was positively correlated with placental weight, but neither placental weight nor embryonic/fetal weight was correlated with number of viable embryos. A parity by gestation day interaction existed; placental weight for P4+ (3.42 ± 0.43 g) was less than for P2/3 (7.55 ± 0.40 g) at day 20–30 ( P < 0.0001), whereas at day 85–90, placental weight of P2/3 (209.5 ± 8.5 g) was less ( P = 0.05) than both G/P1 (235.7 ± 7.3 g) and P4+ (235.4 ± 7.1 g). At day 85–90, fetal brain weight, relative to body weight ( R 2 = 0.61, P < 0.0001), and fetal brain:liver weight ratio ( R 2 = 0.35; P < 0.0001) were negatively related to mean fetal weight, and brain:liver weight ratio showed a trend towards a relationship with number of viable fetuses ( P = 0.08). Parity also affected brain:liver weight ratio ( P = 0.01). Clearly, high ovulation rates in the higher parity sows have the potential to cause excessive in utero crowding of conceptuses in the post-implantation period. Even with moderate crowding, increased brain:liver weight ratios in smaller fetuses in late gestation indicate that uterine capacity impacts fetal development as well as the number of surviving fetuses.