The source and nature of zona lytic factors during zona escape of hamster blastocyts were investigated. When cultured in hamster embryo culture medium (HECM)-2h, all 8-cell embryos (n = 135) developed to zona escaped-blastocysts with complete zona lysis. In addition, 2-cell embryos, when co-cultured with zona escaping-blastocysts (at a ratio of 1:10), exhibited zona lysis. Various other embryos...

(1) Background: The binding sites of melatonin, as a multifunctional molecule, have been identified in human, porcine, and bovine samples. However, the binding sites and mechanisms of melatonin have not been reported in sheep; (2) Methods: Cumulus-oocyte complexes (COCs) were cultured in TCM-199 supplemented with melatonin at concentrations of 0, 10-3, 10-5, 10-7, 10-9, and 10-11 M. Melatonin r...

Embryonic diapause (ED) is a temporary arrest of embryo development and is characterized by delayed implantation in the uterus. ED occurs in blastocysts of less than 2% of mammalian species, including the mouse (Mus musculus). If ED were an evolutionarily conserved phenomenon, then it should be inducible in blastocysts of normally non-diapausing mammals, such as domestic species. To prove this ...

Sheep embryos were examined with the electron microscope in order to characterize their organelles and the changes that occur during the preimplantation period. The first sign of differentiation of trophoblast cells was the appearance of junctions between external cells at the 16-cell stage. Nucleoli developed a granular component suggesting the synthesis of ribosomal RNA at the 16-cell stage a...

Because twin (and sometimes triplet) births commonly occur in sheep, interactions between foetuses of opposite sex may occur during life in utero and affect adult productive or reproductive performance. This was investigated by comparing growth, milk production and reproductive features of female lambs born as twins with a sister (FF) or a brother (FM) or born as triplets with two sisters (FFF)...

Pregnancies obtained by Assisted Reproductive Technologies (ART) are associated with limited maternal nutrient uptake. Our previous studies shown that in vitro culture of sheep embryos is associated with vascularization defects in their placentae and consequent reduction of embryo growth. Autophagy is a pro-survival cellular mechanism triggered by nutrient insufficiency. Therefore, the goal of ...

Research into physiology and embryology has provided a basis for the development of technologies that increase productivity of farm animals through enhanced control of reproductive function. Progestagens, alone or in combination with luteolysins, are used to control the time of oestrus in cattle, sheep and pigs, thus permitting better use of artificial insemination, providing synchronised recip...

the use of donated embryos has offered hope for infertile couples who have no other means to have children. in iran, fertility centers use fertile couples as embryo donors. in this paper, the advantages and disadvantages of this procedure will be discussed. we conclude that embryo-donation should be performed with frozen embryos thus preventing healthy donors from being harmed by fertility drug...

Overnourishing the singleton-bearing adolescent sheep throughout pregnancy promotes maternal tissue synthesis at the expense of the nutrient requirements of the gravid uterus. Consequently, the growth of the placenta is impaired and results in the premature delivery of low-birth-weight lambs relative to moderately fed adolescents of equivalent age. To establish if this phenomenon is unique to t...

BACKGROUND It has been suggested that trophoblast attachment requires co-expression of integrin alpha V beta 3 and its ligand osteopontin at the fetal-maternal interface. Until now the expression patterns of integrin alpha V beta 3 and osteopontin in the pregnant bovine uterus were unknown. The objectives of this study were to localize integrin alpha V beta 3 and osteopontin in bovine and sheep...