Higher Embryonic Survival Research Articles

Aquaculture production of hatchling Hawaiian Bobtail Squid (Euprymna scolopes) is negatively impacted by decreasing environmental microbiome diversity.

AimsThe Hawaiian Bobtail Squid (Euprymna scolopes) is a model organism for investigating host–symbiont relationships. The current scientific focus is on the microbiome within E. scolopes, while very little is known about the microbiome of the tanks housing E. scolopes. We examined the hypothesis that bacterial communities and geochemistry within the squid tank environment correlate with the production of viable paralarval squid.Methods and ResultsTotal DNA was extracted from sediment and filtered water samples from ‘productive’ squid cohorts with high embryonic survival and paralarval hatching, ‘unproductive’ cohorts with low embryonic survival and paralarval hatching. As a control total DNA was extracted from environmental marine locations where E. scolopes is indigenous. Comparative analysis of the bacterial communities by the 16S rRNA gene was performed using next generation sequencing. Thirty‐eight differentially abundant genera were identified in the adult tank waters. The majority of the sequences represented unclassified, candidate or novel genera. The characterized genera included Aquicella, Woeseia and Ferruginibacter, with Hyphomicrobium and Rhizohapis were found to be more abundant in productive adult tank water. In addition, nitrate and pH covaried with productive cohorts, explaining 67% of the bacterial populations. The lower abundance of nitrate‐reducing bacteria in unproductive adult tank water could explain detected elevated nitrate levels.ConclusionsWe conclude that microbiome composition and water geochemistry can negatively affect E. scolopes reproductive physiology in closed tank systems, ultimately impacting host‐microbe research using these animals.Significance and Impact of studyThese results identify the tight relationship between the microbiome and geochemistry to E. scolopes. From this study, it may be possible to design probiotic counter‐measures to improve aquaculture conditions for E. scolopes.

Differential impacts of carp and salmon pituitary extracts on induced oogenesis, egg quality, molecular ontogeny and embryonic developmental competence in European eel.

Low egg quality and embryonic survival are critical challenges in aquaculture, where assisted reproduction procedures and other factors may impact egg quality. This includes European eel (Anguilla anguilla), where pituitary extract from carp (CPE) or salmon (SPE) is applied to override a dopaminergic inhibition of the neuroendocrine system, preventing gonadotropin secretion and gonadal development. The present study used either CPE or SPE to induce vitellogenesis in female European eel and compared impacts on egg quality and offspring developmental competence with emphasis on the maternal-to-zygotic transition (MZT). Females treated with SPE produced significantly higher proportions of floating eggs with fewer cleavage abnormalities and higher embryonic survival. These findings related successful embryogenesis to higher abundance of mRNA transcripts of genes involved in cell adhesion, activation of MZT, and immune response (dcbld1, epcam, oct4, igm) throughout embryonic development. The abundance of mRNA transcripts of cldnd, foxr1, cea, ccna1, ccnb1, ccnb2, zar1, oct4, and npm2 was relatively stable during the first eight hours, followed by a drop during MZT and low levels thereafter, indicating transfer and subsequent clearance of maternal mRNA. mRNA abundance of zar1, epcam, and dicer1 was associated with cleavage abnormalities, while mRNA abundance of zar1, sox2, foxr1, cldnd, phb2, neurod4, and neurog1 (before MZT) was associated with subsequent embryonic survival. In a second pattern, low initial mRNA abundance with an increase during MZT and higher levels persisting thereafter indicating the activation of zygotic transcription. mRNA abundance of ccna1, npm2, oct4, neurod4, and neurog1 during later embryonic development was associated with hatch success. A deviating pattern was observed for dcbld1, which mRNA levels followed the maternal-effect gene pattern but only for embryos from SPE treated females. Together, the differences in offspring production and performance reported in this study show that PE composition impacts egg quality and embryogenesis and in particular, the transition from initial maternal transcripts to zygotic transcription.

Mild hypothermia promotes the viability of in vitro-produced bovine blastocysts and their transcriptional expression of the cold-inducible transcription factor Rbm3 during in vitro culture.

In this study, we evaluated the effects of holding in vitro-produced bovine blastocysts under mild hypothermia (33°C or 35°C), by examining viability and hatching rates of day 7 blastocysts (day 0: in vitro fertilization) cultured for 6 days and transcriptional expression of cold-inducible transcription factors Cirp and Rbm3, implicated in mild hypothermia-induced cellular protection against various types of stress. In the normothermic control (38.5°C), viability of the embryos decreased rapidly after day 10, and most samples were degenerated on day 13. However, mild hypothermia, particularly at 33°C, resulted in maintenance of high embryonic survival rates until day 13 (77.1% on day 13) and significant increases in transcriptional expression of Rbm3 in day 11 embryos compared with those at 38.5°C. Thus, our results suggested that upregulation of Rbm3 may occur in response to mild hypothermia in many bovine embryos, providing insights into the effects of mild hypothermia on embryo quality.

Embryonic development characteristics and host mussel utilization of flat bitterling Acheilognathus rhombeus (Cyprinidae) during winter in Korea

This study aimed to investigate the embryonic development characteristics and host mussel utilization of Acheilognathus rhombeus to determine its adaptations or host utilization for improving survival during winter in the wild; the study was conducted from August 2014 to May 2015. Spawning of A. rhombeus occurred between mid-September and early November, peaking between late September and early October of 2014 when the water temperature was 19–21°C. The embryos of A. rhombeus were first found in early October of 2014 and remained inside the host mussel for 7 months. Development retardation and diapause in embryonic stages (stages C and D) occurred before eye pigmentation and continued until late March of 2015. Subsequently, the embryos resumed development (stage E) when the water temperature increased to about 10 °C. The positions during the development of A. rhombeus embryos in the mussels were mainly present in the farthest suprabranchial cavity and not in the water tube. The embryos were frequently found in the two inner demibranches of the four gills of the mussels regardless of their sex. We assume that embryonic diapause and use of suprabranchial cavity and inner demibranches of the gills of the mussels by A. rhombeus might be the optimal adaptation to maintain high embryonic survival in low water temperature during winter and to avoid interspecific competition.

Donor category and seasonal climate associated with embryo production and survival in multiple ovulation and embryo transfer programs in Holstein cattle

The present study investigated the effect of Holstein donor category (cows vs. heifers) and climate variation (hot vs. cooler season) on the efficiency of in vivo embryo production programs as well as embryo survival after transferred to Holstein recipient cows. A total of 1562 multiple ovulation (MO) procedures (cows: n = 609, and heifers: n = 953) and 4076 embryo transfers (ETs) performed in two dairy herds were evaluated. Donor cows had greater number of CLs (10.6 ± 0.6 vs. 7.5 ± 0.4; P < 0.0001) and ova/embryos recovered (7.6 ± 0.6 vs. 4.6 ± 0.4; P < 0.0001) compared with donor heifers. However, fertilization rate (47.9 vs. 82.4%; P < 0.0001) and proportion of transferable embryos (31.5 vs. 67.4%; P < 0.0001) were lower in donor cows than heifers, respectively. Regardless of donor category, the proportion of freezable embryos was less (P < 0.001) during hot season than in cooler season (21.4 vs. 32.8%). However, greater decline in the proportion of freezable embryos during the hot season was observed in cows (21.7 vs. 10.7%) compared with heifers (46.2 vs. 38.1%; P = 0.01). In contrast, the season on which the embryo was produced (hot or cool) did not affect pregnancy rate on Day 31 (30.5 vs. 31.7%; P = 0.45) and 45 (25.3 vs. 25.1%; P = 0.64) of pregnancy. Regardless of the season in which the embryos were produced, embryonic survival after transferring embryos retrieved from donor cows was greater on Days 31 (36.0 vs. 30.7%; P = 0.001) and 45 (28.3 vs. 23.1%; P = 0.001) of pregnancy when compared with embryos from donor heifers. In conclusion, MO embryo production efficiency decreased during the hot seasons both in cows and heifers; however, the decline was more pronounced in donor cows. Regardless of the embryo source, similar pregnancy rate was observed in the recipient that received embryos produced during the hot and cooler seasons. Curiously, embryos originating from donor cows had higher embryonic survival when transferred to recipient cows than embryos originating from heifers.

444. Embryonic survival in prolific ewes

Introduction: A significant proportion of potential lambs are lost (commonly 15–20%) between ovulation and birth. Little is currently known about factors associated with multiple birth capacity of the uterus which are essential to convert gains in ovulation rate to live lambs. The relationship between maternal uterine and hormonal environment as well as the heritability of embryonic survival (ES) in prolific ewes is investigated. Methods: Litter size (LS) from known ovulation rate (OR) records (n = 6393) collected over 16 years were assessed for heritability with ASREML analysis and to identify the pedigree of outliers. From this flock, closely related high ovulation rate ewes with significantly different litter sizes (High ES; OR2.6/LS2.4 v. Low ES; OR2.9/LS1.6) were selected. Uterine anatomy collected from Day 14 cyclic (n = 5 High and n = 5 Low ES) and Day 16 pregnant ewes (n = 14 high and n = 10 Low) as well as systemic concentrations of hormones indicative of uterine (activin-A, follistatin) and ovarian (inhibin-{α}, progesterone) function were compared. Results and Discussion: ASREML analysis reported ES to be a trait of low repeatability (r = 0.10) and even lower heritability (h2 = 0.04). However, pedigrees of outlier animals indicated a segregation pattern consistent with a single autosomal gene with a major effect on enhanced ES. No anatomical differences between high and low ES ewes were discerned. However, significant differences for circulating levels of activin-A (depressed), time of activin-A peak (earlier), follistatin (elevated), progesterone (early rise) and inhibin-{α} (depressed) concentrations were found around the time of oestrus in High v. Low ES ewes. Given the involvement of activin-A in injury-induced inflammation, these results suggest a role for the activin-follistatin system, possibly through increased residency of immune cells and cytokine activation, for increasing ES in prolific ewes. Acknowledgements; Norma Hudson and Stan Lun for progesterone and inhibin-{α} assays.

Macroenvironment effects on oocytes and embryos in swine

As in other domestic mammals, the interaction between genotype and environment in swine has profound effects on the ultimate phenotype of the individual born. Interactions within the litter in utero add an additional level of complexity in a litter-bearing species like the pig. Nutritional manipulations during the preovulatory period affect the maturity of the follicle and enclosed oocyte, and the metabolic and endocrine mechanisms potentially mediating these effects have been described. Extensive research on lactational catabolism in the first parity sow has established an association between the development of immature follicles and oocytes, and the reduced fertility of these sows when bred at the first postweaning estrus. This negative impact of lactational catabolism appears to be exaggerated in contemporary dam-lines by a minimal delay between weaning and first estrus, further limiting the maturity of the follicle and oocyte at the time of ovulation. Metabolic programming may induce gender-specific loss of embryos by Day 30 and affects embryonic development directly, without significant effects on placental size. In contrast, inadvertent crowding of embryos in utero, particularly evident in a sub-population of mature sows with high ovulation rates and moderate to high embryonic survival to Day 30, significantly limits placental development of crowded litters. However, even at Day 30, moderate crowding in utero also appears to affect myogenesis in the embryo in a gender-specific manner. In the absence of compensatory placental growth after Day 30, classic measures of IUGR are evident in surviving fetuses at Day 90 and at term.

122 INTRACELLULAR ICE FORMATION IN VITRIFIED MOUSE MORULAE DURING WARMING

Vitrification is an ice-free cryopreservation method. However, ice can form during warming if the concentration of cryoprotectant is insufficient. For the best use of vitrified embryos, it is important to know the condition in which intracellular ice (ICI) is formed, since ICI is fatal to the cell. So, we tried to estimate the conditions in which ICI forms in vitrified embryos during warming. Compacted morulae were obtained from ICR mice. Vitrification solutions were prepared by diluting ethylene glycol (EG) with FS solution (PB1 medium containing 30% Ficoll and 0.5 M sucrose) at 10, 20, 30, 40, and 50% (EFS10, EFS20, EFS30, EFS40, and EFS50, respectively). Morulae were treated with the solutions for 30, 60, or 120 s at 25�C, loaded in a straw, and vitrified using liquid nitrogen. The sample was warmed by various methods. The survival of embryos was assessed by their ability to develop to expanded blastocysts in culture. The difference in survival was analyzed by the chi-square test. In addition, the morphology of damaged embryos was examined to estimate the type of injury. It was confirmed that 20% or more EG was necessary to prevent the formation of extracellular ice during cooling without embryos. In the rapid warming protocol (control), in which vitrified samples were directly immersed in 25�C water, high embryonic survival was obtained with EFS30 (79–88%) and EFS40 (96–99%), but not with EFS20 (12–45%) and EFS50 (0–14%). This suggests that embryos vitrified with EFS20 were injured by ICI, whereas those vitrified with EFS50 were injured by the chemical toxicity of the solution. When embryos vitrified with EFS30 and EFS40 were warmed slowly by holding the straw in air at 25�C for 120 s, the survival rate decreased significantly (44–64%), probably because the cytoplasm of the embryos that had vitrified in a state of supercooling devitrified during slow warming. To estimate the condition in which ICI forms, embryos vitrified with EFS30 and EFS40 were kept at intermediate temperatures for various times before being warmed in 25�C water. Compared with control, survival rates decreased significantly by keeping samples for 3 min at -80�C (27–65%), -60�C (16–39%), -40�C (6–26%), or -20�C (33–46%). These results suggest that ICI forms at a wide range of temperatures between -80�C and -20�C, but more likely forms at temperatures between -60�C and -40�C. When the holding time was prolonged to 1 h and 24 h, the survival decreased further (0–58% and 0–14%, respectively). This shows that ICI forms not only quickly but also slowly at an intermediate temperature. From the morphological examination, embryos that should be injured by ICI swelled at recovery in PB1 medium and collapsed in culture, whereas those that should be injured by the toxicity of solution underwent decompaction after culture. This observation reinforces our supposition that slowly warmed embryos are injured by ICI.

Evidence-based Embryo Cryopreservation

Cryopreservation of mammalian animal embryos was first developed using mouse embryos in 1972 and has since been applied to human embryos to utilize surplus embryos in in-vitro fertilization programs: the slow freezing method in the first half of the 1980's and vitrification in the 1990's. Recently, the protocol of vitrification for human embryos has been improved by the ultra-rapid vitrification method in which the rate of cooling is highly improved. It is mainly used as an effective basic technique for cryopreservation of human embryos in current clinical IVF programs due to the extremely high embryonic survival rate after storage.

Thiamine Status in Adult Salmonines in the Great Lakes

AbstractIn 1996 and again in 1999, hatchery personnel noted that some Lake Michigan coho salmon Oncorhynchus kisutch from fall spawning runs on the Platte River weir exhibited abnormal wiggling behavior that was similar to the behavior exhibited by thiamine‐deficient Atlantic salmon Salmo salar, from the Baltic Sea. Samples of eggs or gonads, muscle, and liver from salmon and lake trout Salvelinus namaycush exhibiting abnormal behaviors were collected to determine the extent to which the behaviors were related to a thiamine deficiency. We compared these values with those found in normally behaving fish that produced offspring with high embryonic survival. In all adult fish exhibiting abnormal behavior, tissue residues of thiamine were among the lowest observed in the Great Lakes. Where embryonic survival was assessed, abnormal adult behavior was also associated with very high levels of offspring mortality due to early mortality syndrome. While the overall ecological significance remains to be determined, it appears that adult fish also exhibit neurological dysfunction and mortality associated with thiamine deficiency.

Developmental capacity of ovine zygotes following microinjection of h FVIII-cDNA

The mammary gland of transgenic livestock has recently been shown to be an appropriate site for the production of recombinant human pharmaceutical proteins in biologically active forms. The purpose of our experiments was to generate transgenic sheep in which the human blood clotting factor VIII gene (hFVIII) is expressed in the ovine mammary gland. A total of 920 zygotes was recovered in 119 surgical collections from superovulated donors with a recovery rate of 83.4% (zygotes per corpora lutea). A total of 471 zygotes were microinjected with either the metallothionein human blood clotting factor VIII cDNA (MT-FVIII) or β-lactoglobulin FVIII cDNA (β-Lac VFIII). One to four microinjected zygotes were transferred to 130 recipients of which 76 (58.5%) were diagnosed as pregnant and delivered a total of 124 lambs. Pregnancy rate was significantly increased when four zygotes had been transferred per recipient (70.8% vs. 47.8% to 58.4%). Three transgenic lambs were identified by southern blot analysis (2 males, 1 female). Preliminary culture experiments revealed that microinjection did not impair in vitro development of ovine zygotes. These data indicate that microinjection of FVIII gene constructs into ovine zygotes is compatible with high embryonic survival rates, but the low percentage of transgenic offspring needs further study.

Administration of GnRH at estrus influences pregnancy rates, serum concentrations of LH, FSH, estradiol-17 beta, pregnancy-specific protein B, and progesterone, proportion of luteal cell types, and in vitro production of progesterone in dairy cows

Four experiments were conducted to examine effects of GnRH administered at estrus on various reproductive characteristics in repeat-breeding dairy cows (eligible for third service). In Exp. 1, cows (n = 8 per group) received (i.m.) either saline or 50, 100, or 250 micrograms of GnRH at 12 h after onset of estrus. There was a positive linear (P < .05) effect of dose on concentrations of LH, but not of FSH, in serum at 2 h after the injection. Concentrations of progesterone (P4) were higher (P = .10) through 16 d after estrus in nonpregnant cows that returned to estrus 18 to 24 d after GnRH treatment than in nonpregnant cows given saline. Likewise, among cows with elevated concentrations of P4 through 30 d after estrus (diagnosed pregnant by increased concentrations of pregnancy-specific protein B; PSPB), P4 was higher (P = .10) in those given GnRH than in those given saline. In Exp. 2, concentrations of LH, FSH, and estradiol-17 beta (E2) were similar among 12 cows during the periestrual period before they received (i.m.) 100 micrograms of GnRH or saline at estrus. Concentrations of P4 after estrus were increased 2 d earlier (P < .05) in GnRH- than in saline-treated cows. Among cows with elevated concentrations of P4 and PSPB through 40 d after AI, P4 was higher (P < .05) in those given GnRH than in those given saline. In Exp. 1 and 2, a greater proportion (43 vs 14%; P = .07) of cows given GnRH was pregnant 42 to 56 d after estrus than of those given saline, but calving rate was similar (27 vs 14%). In Exp. 3, average number of LH pulses per 8 h was similar between saline- and GnRH-treated cows on d 1, 3, and 8, but overall concentrations of LH were reduced (P < .05) in GnRH-treated cows. Concentrations and number of pulses of FSH were increased (P < .05) on d 8 after treatment with GnRH. Concentrations of P4 were increased earlier (P < .05) after estrus in GnRH-treated (69 +/- 12 h) than in saline-treated cows (126 +/- 12 h), with higher (P < .05) concentrations of P4 on d 4 to 8. In Exp. 4, eight cows received either 100 micrograms of GnRH or saline at 12 h after onset of estrus (d 0) in a cross-over design.(ABSTRACT TRUNCATED AT 400 WORDS)

Variation in developmental biology of pink salmon (Oncorhynchus gorbuscha) in British Columbia

Pink salmon stocks in British Columbia spawning from August through October were surveyed for variation in developmental biology from 1983 to 1985. Pink salmon in the even-year broodline tended to have higher embryonic survival and proportionately better embryonic and alevin growth at a low incubation temperature (4 °C) than did those in the odd-year broodline. Within a broodline, late-spawning stocks had slightly faster fry emergence timing than did early spawning stocks. Stocks within broodlines had different trends in alevin and fry size with respect to incubation temperature. Pink salmon in the even-year broodline appeared to be better adapted to a colder environment than those in the odd-year broodline. This may reflect a different recent origin of the two broodlines.

POSTMATING FEEDING LEVEL EFFECTS ON CONCEPTION RATE AND EMBRYONIC SURVIVAL IN GILTS

One hundred and twenty-eight gilts were used to evaluate the effect of reducing the level of feeding at estrus on conception rate and embryonic survival. Within each of 4 yr, 16 Yorkshire and 16 Lacombe gilts were penned individually in a piggery, fed 2 kg of diet once daily and 11 days after being observed in estrus were fed 2.5 kg of diet (H). The gilts were mated on the first (day 0) and second day of estrus with two boars of the other breed. On day 1 feed intake was reduced to 1.5 kg (L) per day for one-half of the gilts of each breed. On day 11 the feeding level was switched for one-half of the gilts in each of the two groups to give four feeding level treatments of HH, HL, LH and LL. All gilts were slaughtered between days 30 and 35. The breeds did not differ in average daily gain (ADG), conception rate, or embryonic survival. The Yorkshire gilts had fewer (P &lt; 0.01) corpora lutea (12.0 vs. 13.1) and fetuses (9.3 vs. 11.1) than the Lacombe gilts. The HH and LH gilts had higher ADG than HL and LL gilts (P &lt; 0.01). The HH, HL and LH gilts had higher (P &lt; 0.01) conception rates than the LL gilts (87.1, 86.2 and 87.1% vs. 64.3%, respectively). The numbers of corpora lutea and fetuses were not significantly different among treatments. However, when the H and L treatments to day 10 were compared, the L gilts had more fetuses (11.0 vs. 9.5) and a higher embryonic survival (86.2 vs. 75.8%) than the H gilts (P &lt; 0.05). A body weight maintenance feeding level for 10 days after mating appeared to improve embryonic survival. Key words: Gilts, feed restriction, conception rate, embryonic survival