9 day old Chick Embryo (Part 1)

In order to conduct a comparative study of embryonic anatomy, I needed a few chick embryos to compare with the mouse and lizard embryos. I incubated three fertilized eggs at 37 degrees Celcius for 9-11 days (rotating the eggs 3x daily).

Below is a 9 day old chick embryo. It was euthanized ethically according to IUCAC protocol.

Chick embryo head (left lateral view)

Below is the hindlimb and tail (caudal vertebrae).

Chick embryo caudal vertebrae and hindlimb (left lateral view)

Chick embryo neck, torso and forelimbs (left lateral view)

Below is the chick embryo's forelimb. After the skeletal prep the derived bone structure in the forelimb should become apparent.

Left forelimb of a chick embryo (left lateral view)

Here are the chick embryo's legs.

Chick embryo hindlimbs and tail (right lateral view)

Here is the chick embryo's heart. 

Chick embryo heart and auricles

From the back side, you can see the auricles, which are located upwards towards the aorta.

Chick embryo heart, auricles and aorta

Next, I placed the chick embryo in a 50 ml conical tube of ethanol. After that, it will go into Alcian blue stain for 1 day at room temp It will be covered in foil to keep the light out.

9 day old chick embryo

After letting the chick embryo sit for 1 day in Alcian blue, I noticed the stain was too dark. Next time, I will only let it sit for ~5 hours. Even after destaining the embryo for a day and a half in ethanol, the stain was still too dark. I will find out later if this is representative of the dominance of cartilage in the embryo (with little bone present), or an artifact of the staining.

Chick embryo in Alcian Blue staining solution

I also let the chick sit for 4 hours in 0.8% KOH in a 1% Alizarin red solution. The chick skeleton became very floppy and I was immediately concerned that it would fall apart. In the future, I will use 0.4% KOH or even 0.2%, while reducing the time of exposure greatly. 

Chick embryo skeletal prep and Alcian Blue staining

Here is the base of the skull, the atlas, the axis and other cervical vertebrate. 

Chick embryo cervical vertebrae

The sternum began to detach from the left side, despite using lower levels of KOH. 

Chick embryo ribcage and vertebrae (right lateral view)

Below is the os coxae, the femur and the knee. 

Right hindlimb: femur and knee of the chick embryo

Here is another shot of the knee, with the patella and the distal femur showing. 

Chick embryo distal femur, patella, tibia and fibula (superior view)

Below is the rib cage.

Thoracic vertebrae and ribs of a chick embryo (dorsal/right lateral view)

Next, I will put the chick embryos into Alizarin red staining solution.

All embryos were treated ethically according to IUCAC protocol. 

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