The camp analogue, dbcAMP can stimulate rabbit reproductive functions: I. Effect on ovarian folliculogenesis, ovulation and embryo production

The aim of our study was to test whether a reduction in dietary intake could improve in vitro embryo production in superovulated overfed dairy heifers. Cumulus–oocyte complexes of 16 Prim’ Holstein heifers (14 ± 1 months old) were collected by ovum pick-up (OPU), every 2 weeks following superovulation treatment with 250 μg FSH, before being matured and fertilized in vitro. Embryos were cultured in Synthetic Oviduct Fluid medium for 7 days. Heifers were fed with hay, soybean meal, barley, minerals and vitamins. From OPU 1 to 4 (period 1), all heifers received individually for 8 weeks a diet formulated for a 1000 g/day live-weight gain. From OPU 5 to 8 (period 2), the heifers were allocated to one of two diets (1000 or 600 g/day) for 8 weeks. Heifers’ growth rates were monitored and plasma concentrations of metabolites, metabolic and reproductive hormones were measured each week. Mean live-weight gain observed during period 1 was 950 ± 80 g/day (n = 16). In period 2 it was 730 ± 70 (n = 8) and 1300 ± 70 g/day (n = 8) for restricted and overfed groups respectively. When comparing period 1 and period 2 within groups, significant differences were found. In the restricted group, a higher blastocyst rate, greater proportions of grade 1–3 and grade 1 embryos, associated with higher estradiol at OPU and lower glucose and β-hydroxybutyrate, were observed in period 2 compared with period 1. Moreover, after 6 weeks of dietary restriction (OPU 7), numbers of day 7 total embryos, blastocysts and grade 1–3 embryos had significantly increased. On the contrary, in the overfed group, we observed more <8 mm follicles 2 days before superovulation treatment, higher insulin and IGF-I and lower nonesterified fatty acids in period 2 compared with period 1 (no significant difference between periods for embryo production). After 6 weeks of 1300 g/day live-weight gain (OPU 7), embryo production began to decrease. Whatever the group, oocyte collection did not differ between period 1 and 2. These data suggest that following a period of overfeeding, a short-term dietary intake restriction (6 weeks in our study) may improve blastocyst production and embryo quality when they are low. However, nutritional recommendations aiming to optimize both follicular growth and embryonic development may be different.

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Telomere Length in Norway Spruce during Somatic Embryogenesis and Cryopreservation

Plants ◽

10.3390/plants10020416 ◽

2021 ◽

Vol 10 (2) ◽

pp. 416

Author(s):

Tuija Aronen ◽

Susanna Virta ◽

Saila Varis

Keyword(s):

Somatic Embryogenesis ◽

Telomere Length ◽

Norway Spruce ◽

Genotypic Variation ◽

Production Capacity ◽

Stress Factors ◽

Embryo Production ◽

One Year ◽

Plant Telomeres

Telomeres i.e., termini of the eukaryotic chromosomes protect chromosomes during DNA replication. Shortening of telomeres, either due to stress or ageing is related to replicative cellular senescence. There is little information on the effect of biotechnological methods, such as tissue culture via somatic embryogenesis (SE) or cryopreservation on plant telomeres, even if these techniques are widely applied. The aim of the present study was to examine telomeres of Norway spruce (Picea abies (L.) Karst.) during SE initiation, proliferation, embryo maturation, and cryopreservation to reveal potential ageing or stress-related effects that could explain variation observed at SE process. Altogether, 33 genotypes from 25 families were studied. SE initiation containing several stress factors cause telomere shortening in Norway spruce. Following initiation, the telomere length of the embryogenic tissues (ETs) and embryos produced remains unchanged up to one year of culture, with remarkable genotypic variation. Being prolonged in vitro culture can, however, shorten the telomeres and should be avoided. This is achieved by successful cryopreservation treatment preserving telomere length. Somatic embryo production capacity of the ETs was observed to vary a lot not only among the genotypes, but also from one timepoint to another. No connection between embryo production and telomere length was found, so this variation remains unexplained.

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Laparoscopic Ovum Pick-Up Followed by In Vitro Embryo Production and Transfer in Assisted Breeding Programs for Ruminants

Animals ◽

10.3390/ani11010216 ◽

2021 ◽

Vol 11 (1) ◽

pp. 216

Author(s):

Hernan Baldassarre

Keyword(s):

Pregnancy Rate ◽

Commercial Application ◽

Embryo Production ◽

Breeding Programs ◽

Sheep And Goats ◽

Embryo Recovery ◽

Marker Selection ◽

Holstein Calves ◽

In Vitro Embryo Production

The potential of laparoscopic ovum pick-up (LOPU) followed by in vitro embryo production (IVEP) as a tool for accelerated genetic programs in ruminants is reviewed in this article. In sheep and goats, the LOPU-IVEP platform offers the possibility of producing more offspring from elite females, as the procedure is minimally invasive and can be repeated more times and more frequently in the same animals compared with conventional surgical embryo recovery. On average, ~10 and ~14 viable oocytes are recovered by LOPU from sheep and goats, respectively, which results in 3–5 transferable embryos and >50% pregnancy rate after transfer. LOPU-IVEP has also been applied to prepubertal ruminants of 2–6 months of age, including bovine and buffalo calves. In dairy cattle, the technology has gained momentum in the past few years stemming from the development of genetic marker selection that has allowed predicting the production phenotype of dairy females from shortly after birth. In Holstein calves, we obtained an average of ~22 viable oocytes and ~20% transferable blastocyst rate, followed by >50% pregnancy rate after transfer, declaring the platform ready for commercial application. The present and future of this technology are discussed with a focus on improvements and research needed.

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Signalling pathways and mechanistic cues highlighted by transcriptomic analysis of primordial, primary, and secondary ovarian follicles in domestic cat

Scientific Reports ◽

10.1038/s41598-021-82051-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shauna Kehoe ◽

Katarina Jewgenow ◽

Paul R. Johnston ◽

Susan Mbedi ◽

Beate C. Braun

Keyword(s):

Gene Expression ◽

Transforming Growth Factor ◽

Ovarian Follicle ◽

Mammalian Species ◽

Expression Patterns ◽

Ovarian Follicles ◽

Domestic Cat ◽

Transcriptional Analysis ◽

Ovarian Folliculogenesis

AbstractIn vitro growth (IVG) of dormant primordial ovarian follicles aims to produce mature competent oocytes for assisted reproduction. Success is dependent on optimal in vitro conditions complemented with an understanding of oocyte and ovarian follicle development in vivo. Complete IVG has not been achieved in any other mammalian species besides mice. Furthermore, ovarian folliculogenesis remains sparsely understood overall. Here, gene expression patterns were characterised by RNA-sequencing in primordial (PrF), primary (PF), and secondary (SF) ovarian follicles from Felis catus (domestic cat) ovaries. Two major transitions were investigated: PrF-PF and PF-SF. Transcriptional analysis revealed a higher proportion in gene expression changes during the PrF-PF transition. Key influencing factors during this transition included the interaction between the extracellular matrix (ECM) and matrix metalloproteinase (MMPs) along with nuclear components such as, histone HIST1H1T (H1.6). Conserved signalling factors and expression patterns previously described during mammalian ovarian folliculogenesis were observed. Species-specific features during domestic cat ovarian folliculogenesis were also found. The signalling pathway terms “PI3K-Akt”, “transforming growth factor-β receptor”, “ErbB”, and “HIF-1” from the functional annotation analysis were studied. Some results highlighted mechanistic cues potentially involved in PrF development in the domestic cat. Overall, this study provides an insight into regulatory factors and pathways during preantral ovarian folliculogenesis in domestic cat.

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Evaluation of somatic embryo production during embryogenic tissue proliferation stage using morphology, maternal genotype, proliferation rate and tissue age of Pinus thunbergii Parl

Journal of Forestry Research ◽

10.1007/s11676-021-01311-1 ◽

2021 ◽

Author(s):

Tingyu Sun ◽

Yanli Wang ◽

Lihua Zhu ◽

Xiaowei Liu ◽

Qingtong Wang ◽

...

Keyword(s):

Somatic Embryo ◽

Soluble Sugars ◽

Pinus Thunbergii ◽

Proliferation Rate ◽

Histological Evaluation ◽

Embryogenic Tissue ◽

Cell Physiology ◽

Embryo Production ◽

Maternal Genotype ◽

Somatic Embryo Production

AbstractTo determine the optimal embryogenic capacity (somatic embryo production) of the selected elite nematode-resistant genotypes of Pinus thunbergii, variables such as embryogenic tissue (ET) morphology, maternal genotype, proliferation rate and tissue age were analyzed. ET morphology and histological evaluation of the proliferation stage showed a decrease in filamentous clump and protuberant surfaces and a decline in the acetocarmine-staining area, which indicates a decrease in somatic embryo production (SEP). Variations in cell physiology during the proliferation stage showed that SEP was positively correlated with soluble sugars and proteins, but negatively correlated with starch, peroxidase, and superoxidase. In addition, SEP was significantly (p < 0.001) affected by maternal genotype, tissue age and proliferation rate. Moreover, SEP was positively correlated with proliferation rate (r = 0.98, p < 0.001), but negatively correlated with tissue age (r = − 0.95, p < 0.001). In general, the results suggest that SEP could be assessed in ET proliferation stages by the apparent cell morphology, histology, proliferation rate and tissue age, which provides novel insights for evaluating the ET maturation capacity (number of somatic embryos) during the proliferation stage of P. thunbergii somatic embryogenesis.

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