<div><strong>Background: </strong>Vitamin A has potentially harmful effects on the development of chick embryos even at very low dose concentration. Vitamin A different doses cause embryotoxic and teratogenic effects on the developing of the chick embryo. Hence, due to teratogenicity of this vitamin it can be used with utmost caution during pregnancy. &nbsp; &nbsp; &nbsp;<br />
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<strong>Methods:</strong> Fertile chicken eggs (obtained from local hatchery) were injected with three doses of Vitamin A (15 IU/ml, 30 IU/ml, 75 IU/ml) into the center of the egg yolk. Morphometric parameters as mortality rate, body weight (g), crown rump length (mm) of embryo and Frequency % of different anomalies gross malformations were measured. Whole chicken samples were taken by 4<sup>th</sup>, 8<sup>th</sup> and 18th incubation day. Daam, Hox and Tbx genes expression profile were analyzed.<br />
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<strong>Result:</strong> Dose-dependent defects and embryo lethality in the chick embryos developed when exposed to higher concentrations. Our study record for the first time the duplication in the heart, brain and eye. Also showed duplication of the neck forming S-shaped showed in some malformed chick embryos. The three investigated genes showed different fluctuations confirming the malformations detected.</div>


<div>Impact of Vitamin A on the Expression Profile of Development-Controlling Genes in Chick Embryos</div>


<div style="text-align: justify;">Blood cells are responsible for constant maintenance and immune protection of every cell type of the body and this relentless and brutal work requires cells that have the greatest powers of self-renewal and are designated as Hematopoietic progenitor cells (HPCs).Peripheral blood stem cells in circulation have become the most common source of hematopoietic stem cells intended for transplantation after minimal manipulation. Homeo box (Hox), sonic hedgehog (SHH), and Wingless-type MMTV integration site family (Wnt) are known to modulate the self-renewal and expansion of hematopoietic progenitor/stem cells in humans and mice. Unlike cytokines, Hox, SHH, and Wnt are highly conserved among species from flies to humans but studies regarding the self-renewal and expansion of the HSC are extremely limited in dogs.</div>

Impact of Vitamin A on the Expression Profile of Development-Controlling Genes in Chick Embryos

Real-time Expression of Stemness and Self-Renewal Genes in Canine Hematopoietic Progenitor Cells