Cellular and morphological characterization of blastoderms from freshly laid broiler eggs

Abstract

The pioneering study of Eyal-Giladi and Kochav (EG&K; Eyal-Giladi and Kochav, 1976) on the early developmental stages-from fertilization, through oviposition, to the gastrulation process-set the standard for characterizing chicken embryos, and has been used in numerous studies over the years. During uterine development, the chicken embryo undergoes dramatic changes, extremely rapid cell cycles, massive cell death, and axial determination processes. However, once the egg is laid, the temperature drops and the embryo enters into a diapause-like state. This phenomenon is utilized to store fertile eggs prior to incubation. The ability to resume development to hatching, following storage, relies on several factors, including the number of living cells and the embryonic developmental stage. These factors are highly influenced by the storage conditions-mainly duration and temperature. Thus, to study the effects of storage conditions on embryonic viability, a comprehensive characterization of the starting point-shortly after oviposition-is needed. In this study, we characterized freshly laid broiler eggs from Ross 308 flocks for embryonic developmental stage, total cell count, and cell viability. Using the novel high-resolution episcopic microscopy (HREM) system, we show, for the first time, high-resolution 3D morphological models of blastoderms which allow for highly accurate embryonic staging. Staging was also done under a dissecting microscope thus allowing for a direct side-by-side comparison of the two methods. Analysis of freshly laid blastomeres showed that the total nucleus count increases with developmental stage from ∼60,000 at stage X EG&K to ∼130,000 at stage XIII EG&K, whereas the proportion of mitotic index and dying cells at oviposition are ∼2% and ∼5%, respectively. Moreover, staging embryos from young and old flocks revealed that the blastoderms of the old flocks are more developed. Specifically, the predominant embryonic stages were XI and XII EG&K in young and old flocks, respectively. Collectively, we characterized parameters that can serve to analyze the maladaptive effects of prolonged storage under various conditions on embryo survival.

Pre-Incubation and Turning During Long Storage as a Method of Improving Hatchability and Chick Quality of Japanese Quail Eggs

“…Otherwise, it may result in a reduction in the quality of the obtained chicks. In general, the quality of chicks obtained from eggs of the older quail flock was lower, which confirms previous studies in chickens (Tona et al, 2003(Tona et al, , 2004Pokhrel et al, 2018). As a consequence of the SPIDES study used in this study, the quality of the chicks did In conclusion, to obtain a higher number of high quality quail chicks from eggs stored for 12 d, it is recommended to use PI, particularly in line with the scheme of the discussed EG SPIDES profile with the concomitant T every 12 h. Application of the EG SPIDES profile improves hatchability but it contributes to prolongation of the HW duration, which may impede clutch organization in hatcheries.…”

The Tomato BLADE ON PETIOLE and TERMINATING FLOWER Regulate Leaf Axil Patterning Along the Proximal-Distal Axes

“…SlBOP2 and SlBOP3 expression was decreased to less than 40% of WT levels, while SlBOP1 transcript was reduced to 60% of WT levels (Supplementary Figure S2 ). To study the impact of SlBOP reduced expression on the axil phenotype, we utilized High Resolution Episcopic Microscopy (HREM (( Weninger and Mohun, 2007 ; Pokhrel et al, 2017 ) to create three dimensional (3D) reconstructions of WT and 35S:amiR- SlBOP1-3 leaf axils ( Figure 1 ). Altered morphology of the 35S:amiR- SlBOP1-3 leaf axil in comparison to WT, was evident in the HERM 3D images.…”

“…Tissues were fixed overnight in 4% paraformaldehyde (PFA) (v/v), rinsed in PBS buffer and dehydrated through an ethanol series up to 95% ethanol. Fixed and dehydrated tissues were infiltrated with catalyzed monomer A of the JB-4 embedding kit (Electron Microscopy Sciences) containing eosin and acridin orange dyes as previously described ( Weninger and Mohun, 2007 ; Pokhrel et al, 2017 ). Samples were incubated for 7 days on a revolving shaker at room temperature in the dark.…”

High-Resolution Episcopic Microscopy (HREM): Looking Back on 13 Years of Successful Generation of Digital Volume Data of Organic Material for 3D Visualisation and 3D Display

“…Chick embryos of very early to late developmental stages were already examined, as shown in Figure 2. Embryos of the blastoderm stage [90,91] were used for researching the effect that the storage of eggs has on embryonic development and viability. Embryos of late developmental stages have been successfully used for analysing the effect of hemodynamic alterations on the topology and remodelling of the cardiac outflow [72], and for producing metric definition of the dimensions of the great intrathoracic arteries to serve as reference data for such studies [73].…”