BackgroundTGF-β signaling pathways regulate several crucial processes in female reproduction. AKT is a non-SMAD signaling pathway regulated by TGF-β ligands essential for oocyte maturation and early embryonic development in the mouse, but its regulatory role in bovine early embryonic development is not well established. Previously, we demonstrated a stimulatory role for follistatin (a binding protein for specific members of TGF-β superfamily) in early bovine embryonic development. The objectives of the present studies were to determine the functional role of AKT signaling in bovine early embryonic development and embryotrophic actions of follistatin.MethodsWe used AKT inhibitors III and IV as pharmacological inhibitors of AKT signaling pathway during the first 72 h of in vitro embryo culture. Effects of AKT inhibition on early embryonic development and AKT phosphorylation were investigated in the presence or absence of exogenous follistatin.ResultsPharmacological inhibition of AKT signaling resulted in a significant reduction in early embryo cleavage, and development to the 8- to 16-cell and blastocyst stages (d7). Treatment with exogenous follistatin increased AKT phosphorylation and rescued the inhibitory effect of AKT inhibitors III and IV on AKT phosphorylation and early embryonic development.ConclusionsCollectively, results suggest a potential requirement of AKT for bovine early embryonic development, and suggest a potential role for follistatin in regulation of AKT signaling in early bovine embryos.Electronic supplementary materialThe online version of this article (10.1186/s12958-017-0318-6) contains supplementary material, which is available to authorized users.

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A study of the histology of the epididymis of seventeen adult buffalo bulls ranging from 2 to 4 years of age was carried out. Tissues were collected at slaughter, fixed in formalin and paraffin sectioned. The histologic structure of 8 regions of the epididymis is described, and compared with descriptions of the epididymis of other species.

Contents:The periodic acid-Schiff (PAS) reactive materials of epididymal and ejaculated spermatozoa have been studied in Friesian bulls, buffalo bulls, rams and camels. In the four species, the cytoplasmic droplets displayed strong PAS reaction which did n o t appear t o change markedly during epididymal transit. Only in ram a slight reduction was noted in cauda epididymal and vas deferens spermatozoa. In Friesian bulls, the acrosomes of epididymal spermatozoa exhibited moderate PAS reaction which increased on passage t o the vas deferens and after ejaculation. In the buffalo the reaction increased in cauda epididymal and vas deferens spermatozoa but returned again to mderate on ejaculation. In the camel the acrosomes of caput spermatozoa showed strong reaction which was sharply reduced on passage beyond. Meanwhile in rams the acrosomes of spermatozoa obtained f r o m any level of the genital tract exhibited weak PAS reaction. The postnuclear reagions, middle pieces and tails of bull, buffalo, ram and camel spermatozoa showed varying degrees of PAS reaction. The pattern of change during transit of spermatozoa differed f r o m species to another which might be related to the nature of maturational processes. Inhalt: PAS-reaktive Polysaccharide in Saugetierspermien wahrend der Passage durch den Nebenhoden PAS-positive Reaktionen von Nebenhodenspermien und ejakulierten Spermien wurden an Friesian-und Biiffelbullen, Schafbocken und Kamelhengsten untersucht. In allen 4 Spezies zeigten die Cytoplasmatropfchen starke Reaktion, die sich wahrend der Nebenhodenpassage nicht merklich veranderte. Nur beim Schafiock wurde eine geringfugzge schwachere Reaktion bei Spermien aus dem Nebenhodenschwanz und dem Vas deferens beobachtet. Bei Friesianbullen zeigte das Akrosom der Nebenhodenspermien eine mittelstarke PAS-Reaktion, die nach Passage durch den Samenleiter und nach der Ejakulation weiter verstarkt war. Beim Biiffel war die Reaktion in der Cauda und Vas deferens verstarkt, in ejakulierten Spermien aber wieder schwacher. Beim Kame1 war das Akrosom der Caput-Spermien stark positiv, bei der nachfolgenden Passage nahm die Reaktion deutlich ab. Das Akrosom der Schafspermien war in allen Organabschnitten nur schwach angefarbt. Bei allen vier untersuchten Spezies zeigten die anderen Spermienbereiche (postnukleare Region, Mittelstiick, Schwanz) sehr unterschiedliche Reaktionen. Die Veranderungen whhrend er Nebenhodenpassage waren zwischen den Spezies unterschiedlich und vermutlich abhangzg von Unterschieden in den Reifungsprozessen. US.