Early Embryonic Loss Due to Heat Stress

Hansen, Peter J.

doi:10.1002/9781118833971.ch64

Cited by 8 publications

(8 citation statements)

References 97 publications

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“…Differences are reported in transcript abundance among embryos produced by IVF of oocytes collected in summer versus winter in bovine (Gendelman and Roth 2012a). Seasonal effects on blastocyst formation generally result in decreased competence of cleaved embryo development, rather than competence of the oocyte to cleave (Hansen 2015). Heat stress impairs augmentation of molecules essential for early embryonic development in the oocyte.…”

Section: Introductionmentioning

confidence: 99%

Developmental competence and expression profile of genes in buffalo (Bubalus bubalis) oocytes and embryos collected under different environmental stress

et al. 2016

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The study examined the effects of different environmental stress on developmental competence and the relative abundance (RA) of various gene transcripts in oocytes and embryos of buffalo. Oocytes collected during cold period (CP) and hot period (HP) were matured, fertilized and cultured in vitro to blastocyst hatching stage. The mRNA expression patterns of genes implicated in developmental competence (OCT-4, IGF-2R and GDF-9), heat shock (HSP-70.1), oxidative stress (MnSOD), metabolism (GLUT-1), pro-apoptosis (BAX) and anti-apoptosis (BCL-2) were evaluated in immature and matured oocytes as well as in pre-implantation stage embryos. Oocytes reaching MII stage, cleavage rates, blastocyst yield and hatching rates increased (P \ 0.05) during the CP. In MII oocytes and 2-cell embryos, the RA of OCT-4, IGF-2R, GDF-9, MnSOD and GLUT-1 decreased (P \ 0.05) during the HP. In 4-cell embryos, the RA of OCT-4, IGF-2R and BCL-2 decreased (P \ 0.05) in the HP, whereas GDF-9 increased (P \ 0.05). In 8-to 16-cell embryos, the RA of OCT-4 and BCL-2 decreased (P \ 0. 05) in the HP, whereas HSP-70.1 and BAX expression increased (P \ 0.05). In morula and blastocyst, the RA of OCT-4, IGF-2R and MnSOD decreased (P \ 0.05) during the HP, whereas HSP-70.1 was increased (P \ 0.05). In conclusion, deleterious seasonal effects induced at the GVstage carry-over to subsequent embryonic developmental stages and compromise oocyte developmental competence and quality of developed blastocysts.

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Section: Introductionmentioning

confidence: 99%

Developmental competence and expression profile of genes in buffalo (Bubalus bubalis) oocytes and embryos collected under different environmental stress

et al. 2016

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“…Results from both studies indicate that, the pro-apoptotic signals can be activated to initiate apoptosis at a later stage of embryo development after the embryonic genome activation. The caspase deoxyribonuclease and the resistance of mitochondrial depolarization at 2 cell results in inhibition of apoptosis or the presence of apoptosis at a lesser amount at 2 cell stage in cattle embryo (Hansen, 2015).…”

Section: ˚C)mentioning

confidence: 99%

145 the Role of Cell Apoptosis on in Vitro-Produced Beef Cattle Embryos

Nkadimeng

2017

Reprod. Fertil. Dev.

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Successful in vitro development of embryos is dependent upon maintenance of cellular function in the embryonic microenvironment. Exposure of pre-implantation embryos to a variety of cellular stresses can induce apoptosis in all or a fraction of blastomeres. Among the conditions that can induce apoptosis in cattle embryo production in vitro are heat shock, media composition, oxygen levels, and tumour necrosis factor (TNF)-α. The aim of the study was therefore to evaluate the in vitro culture environment of embryos in terms of cell apoptosis through caspase and DNA fragmentation evaluation. A total of 1200 immature oocytes were collected at slaughter from indigenous South African cow ovaries. The cumulus-oocyte complexes were randomly allocated into 2 maturation temperatures, 39°C and 41°C (200/temperature /replicated 6 times), and cultured in M199 + FSH-LH-oestradiol medium under oil at 100% humidity and 5% CO2 for 24 h. Postmaturation, oocytes were subjected to normal subsequent embryo conditions (Rynkowska et al. 2011 Biotechnol. Comput. Biol. Bionanotechnol. 92, 45–53). All matured oocytes were fertilized for 6 h with frozen-thawed Nguni bull semen from 10 bulls replicated 5 times at a concentration of 265 × 106 sperm cells/mL in Bracket and Oliphant medium under oil. The presumptive zygotes from each treatment were cultured into SOF-BSA medium under oil and incubated at 39°C for assessment of cleavage rate post IVF. Produced embryos were divided into 3 groups: 2–4 cell, ≥8 cell embryos, and blastocyst. Two- to four-cell embryos were removed at Day 2, ≥8 cell at Day 5 (mainly 8-cell, morula, and cavitated blastocyst), and expanded blastocyst at Day 7 of embryo culture to determine caspase activity and DNA fragmentation for evidence of apoptosis. Caspase was performed using colourimetric assay on a 96-well microplate reader and monitored at 450 nm reference filter. The DNA fragmentation was examined using the TUNEL assay method and imaging was done using the Alexa Fluor® 488 emission at 519 nm. Data were analysed using SAS 9.2 software (SAS Institute Inc., Cary, NC, USA), and Shapiro-Wilks test was used on the standardized residuals to test for deviations from normality, means of significant effects were compared using Student’s t-l.s.d. at the 95% confidence interval. There was no significant difference on the cleavage rates [39°C (72.0 ± 22.70) and 41°C (67.2 ± 18.9)] and blastocysts [39°C (11.4 ± 2.6) and 41°C (11.2 ± 6.3)] from both maturation temperatures. Caspase activity showed no significant difference on 2–4 cell [39°C (0.015 ± 0.001) and 41°C (0.016 ± 0.002)] and ≥8 cell embryos at both temperatures [39°C (0.022 ± 0.007a) and 41°C (0.032 ± 0.013)]. However, blastocyst differed significantly at both temperatures [39°C (0.037 ± 0.012) and 41°C (0.053 ± 0.005)]. A higher (P < 0.05) DNA fragmentation was observed at 2–4 cell (6.5 ± 2.9), ≥8 cell (13.3 ± 3.1), and blastocyst (48.0 ± 8.2) for embryos produced from 41°C matured oocytes compared to the 39°C maturation group [2–4 cell (2.2 ± 1.2), ≥8 cell (4.5 ± 1.9), and blastocyst (9.7 ± 6.7)]. It is therefore concluded that embryos produced from 41°C matured oocytes can have the same developmental capacity as the 39°C maturation group. Moreover, both temperatures can show signs of apoptosis, however, with more apoptosis evidence in the 41°C than the 39°C maturation group.

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“…Due to hormonal imbalance, the follicular steroidogenic activity is altered and may be suggested that it mostly causes the lowering of fertility in buffalo (Ali, 2015). In addition to hormonal changes, environmental heat stress and type of housing provided to the animal can also serve as effective source of embryonic losses (Hansen, 2014;Dash et al, 2016). An earlier study shows that embryonic mortality was higher between days 31 and 55 of gestation in dairy cattle (Forar et al, 1996).…”

Section: Introductionmentioning

confidence: 99%

Long Term Administration of Exogenous Oxytocin: Effects on Pregnancy Rate, and Embryonic and Fetal Losses in Nili-Ravi Buffaloes

2020

THE JAPS

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It is a common perception among dairy farmers in Pakistan that oxytocin (OT) injection negatively effects on buffalo reproduction parameters. Therefore, current study was conducted to investigate the outcomes of OT on numbers of AI per conception, pregnancy rate, embryonic and fetal losses (EFL). For this purpose, Nili-Ravi buffaloes (n=23) were randomly divided into three groups, G1; n=7 (control), G2; n=8 (low dose 10 i.u.) and G3; n=8 (high dose 30 i.u.). The OT injection was given twice daily at morning and evening milking until 154 days post calving. At heat, AI was performed. Ultrasonography and blood sampling were done on days 30, 45 and 60 post AI to monitor pregnancy and progesterone, respectively. Results showed significant (P≤0.05) increase of AI services per conception in G2 & G3 as compared to G1. Furthermore, results revealed that chances of the animals to become pregnant were 0.227 and 0.094 times in low (G2) and high doses (G3) in comparison to control (G1), respectively, and was lower significantly (P≤0.05). Similarly, pregnancy rate was remained unaffected and was non-significant (P>0.05) on day 45 vs day 30. However, it was significantly (P≤0.05) lower on day 60 vs day 30. Overall, pregnancy rate was decreased (P≤0.05) in oxytocin treatments comparable to control. Parity and days in milk had no significant effect on pregnancy rate among treatments (G1, G2 and G3), respectively. Moreover, EFL losses were non-significant (P>0.05) among treatments but losses trend was more in G2 & G3 parallel to G1. Result also showed non-significant (P>0.05) decrease in P4 on days 30 and 45 while significant (P≤0.05) on day 60 in G2 & G3 as compared to G1 among treatment groups. It may be concluded that long term OT injections of both low and high doses cause significant losses in terms of increase in AI services per conception and decrease pregnancy rate with higher EFL in Nili-Ravi buffaloes.

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Early Embryonic Loss Due to Heat Stress

Cited by 8 publications

References 97 publications

Developmental competence and expression profile of genes in buffalo (Bubalus bubalis) oocytes and embryos collected under different environmental stress

Developmental competence and expression profile of genes in buffalo (Bubalus bubalis) oocytes and embryos collected under different environmental stress

145 the Role of Cell Apoptosis on in Vitro-Produced Beef Cattle Embryos

Long Term Administration of Exogenous Oxytocin: Effects on Pregnancy Rate, and Embryonic and Fetal Losses in Nili-Ravi Buffaloes

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