Reproduction, Fertility and Development
Number 4 2013
In animal husbandry, freezing is widely used for the storage and transportation of embryos destined for transfer; however, high lipid content in embryos makes them sensitive to low temperatures. In this study, l-carnitine, an enhancer of lipid metabolism, has been successfully applied during embryo culture to improve development and freezing tolerance of bovine embryos. The use of l-carnitine offers a safe and non-invasive way to improve the efficacy of embryo-freezing technology in cattle.
The post hatching development (PHD) systems is a potential tool to verify the quality of in vitro produced embryos without transfer then for the recipient uterus. The study aimed to evaluate the efficiency of the system by comparing embryos produced in PHD system with the in vivo produced ones. The results showed that the system is not efficient enough to be use as a routine method for embryo evaluation.
As a valuable technology in assisted reproduction, egg freezing needs to be further evaluated, such as effects on cytoplasm quality and the nucleus. Through studying eggs frozen at different times after intracytoplasmic sperm injection or artificial activation, we found that differences in ploidy formation existed, whereas cytoskeleton assembly was not altered and there was no difference in blastocyst development compared with normal zygotes. We believe that proper freezing not only maintains the egg cytoskeleton but also contributes to eggs being able to maintain their reprogramming ability for spermatozoa during freezing, which could become a useful tool to monitor and optimize egg freezing.
Although it is well known that actin is involved in multiple processes during cell division, which also includes early embryo development, the molecular mechanism is still unclear. In the present study we found that inhibition of the actin nucleator Arp2/3 complex caused a decrease in actin within cells and the failure of embryo development. Our results indicate that the Arp2/3 complex is involved in mouse embryo development through the regulation of actin assembly.
The production of embryos using genetic material only from the father is difficult and the efficiency of this technique is extremely low in mammalian species. Mimicking several physiological processes during normal fertilisation, we treated bovine spermatozoa prior to the production of embryos and successfully improved their developmental capacity. Our results contribute to the understanding of the paternal contribution to embryonic development and to the production of transgenic animals.
Fetal growth is adversely affected by environmental hypoxia and oxidative stress in sheep flocks kept at high altitudes. The administration of antioxidant vitamins may prevent these effects. Because placental steroidogenesis is a key factor for fetal growth, we evaluated the effects of supplementation with vitamins C and E on plasma concentrations of progesterone and 17β-oestradiol in high-altitude pregnancies in sheep. The concentrations of both hormones were higher in the supplemented groups, favouring fetal development and, thus, also improving sheep production at high altitudes.
This research was focused on the Senegalese sole, a flatfish with high commercial value in Mediterranean aquaculture. The aim of this work was to characterise vasa gene to determine its usefulness as a molecular marker for germ cells during embryonic, larval development, juvenile and adulthood. We demonstrated that vasa products (mRNAs and proteins) allow germ cells identification establishing a suitable molecular tool for germinal cells biotechnology for Senegalese sole reproduction.
The aim of this study was to determine the effect of long-term estradiol-17β (E2) exposure (simulation of pathological states occurring with estrogen overproduction) on innervation pattern of ovaries in adult gilts. In the ovaries of E2-injected gilts, the disturbances in the development of follicles, an increase in the total population of nerve fibers, including fibers containing DβH, NPY, and GAL were observed. These results suggest that hyperestrogenism caused by endogenous or exogenous estrogens may affect the innervation pattern of ovaries and consequently their function(s) and further support the importance of estrogens as modulators of neuronal plasticity.
Melatonin, an indoleamine originally identified in the pineal gland, affects ovarian functions, and previous studies have suggested that melatonin is synthesised in the ovary. This study demonstrates that in rat oocytes, melatonin is synthesised from serotonin through the same pathway as in the pineal gland. Melatonin synthesised in the oocyte may be implicated in its own growth and/or maturation, for example, by acting as a calmodulin antagonist and/or an antioxidant.
Camelids are often wrongly considered as small bovine or big ovine in terms of nutritional requirements. Specific nutritional planes are essential for the reproductive management optimisation. Studies investigating the link between nutrition and reproductive performance are particularly needed in the male. The present study investigated the effect of different nutritional planes and found detrimental effects of energy excess on the biochemical characteristics of alpaca semen.
The specific roles of microRNAs in terms of germ cell development are largely unknown. The present study found that spindle formation and the actin cap were affected after microinjection of miR-335-5p or its inhibitor during mouse oocyte maturation. On the basis of the results of the present study, it appears that microRNA mir-335-5p may be involved in cytoskeleton dynamics in mouse oocyte meiosis.
Little is known about the use of mated bitches with in vivo-fertilised embryos as recipients for cloned embryos in dog cloning. Our study demonstrated successful production of cloned dogs with wild-type pups by using mated recipients as surrogate mothers. Thus, employing mated recipients could be a new method that may improve the efficiency of cloning in dogs and help with understanding the underlying mechanism of implantation.
The derivation of robust livestock embryonic stem cell lines, which promise a wide range of practical applications in agricultural biotechnology, including dissemination of elite genetics and sophisticated genome editing, has proven difficult to date. We examined the effect of small molecules that prevent differentiation of stem cells and methods of cryopreservation on long-term survival and retention of stem-cell characteristics of embryo-derived stem cells in the cow. We show that vitrification, which minimises cell damage, was effective for freezing cells, which could be maintained as stem cells for more than 240 days in culture.