Cracking Open the Secrets

Zoo InternQuest is a seven-week career exploration program for San Diego County high school juniors and seniors. Students have the unique opportunity to meet professionals working for the San Diego Zoo, Safari Park, and Institute for Conservation Research, learn about their jobs, and then blog about their experience online.  Follow their adventures here on the Zoo’s website!

Zoo InternQuest visited the Reproductive Physiology Department at the San Diego Zoo Institute for Conservation Research, where egg-static interns were able to open up fertilized chicken eggs in the lab and get a peek inside. The leader of our expedition was Dr. Tom Jensen, whose great love of kiwis (the bird, not the fruit) led him to study the conservation research of endangered birds.

Our presenters Dr. Tom Jensen, Scientist, and Ms. Kaitlin Croyle, intern, both from the Reproductive Physiology Division at the San Diego Institute for Conservation Research, explained the complicated processes of sexing eggs works. Dr. Jensen addressed a problem that many people overlook: since San Diego does not experience real winters, how are birds supposed to know when it is breeding season? Dr. Jensen said that the best way to deal with this is to control the bird's estrogen levels. By using a pump device affixed to an individual bird, researchers can periodically inject hormones with minimal stress to the animal.

Our presenters Dr. Tom Jensen, Scientist, and Ms. Kaitlin Croyle, intern, both from the Reproductive Physiology Division at the San Diego Institute for Conservation Research, explained the complicated processes of sexing eggs works. Dr. Jensen addressed a problem that many people overlook: since San Diego does not experience real winters, how are birds supposed to know when it is breeding season? Dr. Jensen said that the best way to deal with this is to control the bird’s estrogen levels. By using a pump device affixed to an individual bird, researchers can periodically inject hormones with minimal stress to the animal.

Dr. Jensen showed InternQuest a variety of eggs he has worked with. Some examples include the blue crane and the brown kiwi. There was even an egg from a turtle. According to Ms. Croyle, the team is working on applying these techniques to reptiles, many of who are also endangered species.

Dr. Jensen showed InternQuest a variety of eggs he has worked with. Some examples include the blue crane and the brown kiwi. There was even an egg from a turtle. According to Ms. Croyle, the team is working on applying these techniques to reptiles, many of who are also endangered species.

In the Reproductive Physiology Department, we were shown a variety of eggs that researchers work with, such as kiwi eggs. Kiwis have the biggest egg-to-body-size ratio of any bird species. Some kiwi eggs are 20% of the mother's body weight. Yet, despite this, kiwis are able to lay 100 eggs in a lifetime! These birds historically lacked predators in their native New Zealand habitat but due to the introduction of predators, such as dogs and cats, the eggs are now vulnerable when incubating.

In the Reproductive Physiology Department, we were shown a variety of eggs that researchers work with, such as kiwi eggs. (Sabrina is holding one of the eggs they showed us.) Kiwis have the biggest egg-to-body-size ratio of any bird species. Some kiwi eggs are 20% of the mother’s body weight. Yet, despite this, kiwis are able to lay 100 eggs in a lifetime! These birds historically lacked predators in their native New Zealand habitat but due to the introduction of predators, such as dogs and cats, the eggs are now vulnerable when incubating.

My fellow intern Tori is using a sanding belt to open up her chicken egg. At the Reproductive Physiology Department, we all had the opportunity to try this process with a power sander. With a light touch, one can sand down a small section off of an egg’s shell, leaving only the membrane to keep the egg from leaking. This allows researchers to have access to the life inside the egg. Luckily, all of the interns were successful on the first try!

My fellow intern Tori is using a sanding belt to open up her chicken egg. At the Reproductive Physiology Department, we all had the opportunity to try this process with a power sander. With a light touch, one can sand down a small section off of an egg’s shell, leaving only the membrane to keep the egg from leaking. This allows researchers to have access to the life inside the egg. Luckily, all of the interns were successful on the first try!

During the egg sanding process, there could be an "egg-cident," like applying too much pressure to the sander. The egg membrane could burst and egg yolk could fly everywhere! Dr. Jensen’s students have a good sense of humor, which is why there is an "egg-mergency" kit in the laboratory. It is equipped with salt, pepper, a pretend frying pan and cleaning supplies, so Reproductive Physiology staff are never unprepared.

During the egg sanding process, there could be an “egg-cident,” like applying too much pressure to the sander. The egg membrane could burst and egg yolk could fly everywhere! Dr. Jensen’s students have a good sense of humor, which is why there is an “egg-mergency” kit in the laboratory. It is equipped with salt, pepper, a pretend frying pan and cleaning supplies, so Reproductive Physiology staff are never unprepared.

Dr. Jensen, Scientist demonstrated the procedure for peeling back the membrane just beneath the eggshell. He explains to us the anatomy of a fertilized egg that is in stage twelve of development.

Dr. Jensen, Scientist demonstrated the procedure for peeling back the membrane just beneath the eggshell. He explains to us the anatomy of a fertilized egg that is in stage twelve of development.

Ms. Croyle, an intern and a master’s student from Cal State San Marcos works with Dr. Jensen on current projects including one very interesting one: making kiwis from chickens. It may sound bizarre, but the Reproductive Physiology team is researching spermatogonia, which are sperm stem cells. Despite the species barrier, it may be possible to use chickens to produce kiwi sperm, which can then be used in artificial insemination. This research might save the kiwi and other endangered species from extinction!

Ms. Croyle, an intern and a master’s student from Cal State San Marcos works with Dr. Jensen on current projects including one very interesting one: making kiwis from chickens. It may sound bizarre, but the Reproductive Physiology team is researching spermatogonia, which are sperm stem cells. Despite the species barrier, it may be possible to use chickens to produce kiwi sperm, which can then be used in artificial insemination. This research might save the kiwi and other endangered species from extinction!

Dr. Jensen showed interns how to carefully remove the egg’s membrane after the shell had been sanded. Using tweezers and a microscope connected to a camera, Reproductive Physiology personnel are able to get an inside look at life within the shell, note the stage of development, and take blood samples.

Dr. Jensen showed interns how to carefully remove the egg’s membrane after the shell had been sanded. Using tweezers and a microscope connected to a camera, Reproductive Physiology personnel are able to get an inside look at life within the shell, note the stage of development, and take blood samples.

Dr. Jensen showed InternQuest a variety of eggs he has worked with. Some examples include the blue crane and the brown kiwi. There was even an egg from a turtle. According to Ms. Croyle, the team is working on applying these techniques to reptiles, many of who are also endangered species.

Dr. Jensen showed InternQuest a variety of eggs he has worked with. Some examples include the blue crane and the brown kiwi. There was even an egg from a turtle. According to Ms. Croyle, the team is working on applying these techniques to reptiles, many of who are also endangered species.

Here is a close-up of my chicken egg just after I removed the membrane. As Dr. Jensen put it, the veins that envelop the yolk serve as a lunchbox for the developing embryo. It delivers nutrients to the soon-to-be chick to help it grow.

Here is a close-up of my chicken egg just after I removed the membrane. As Dr. Jensen put it, the veins that envelop the yolk serve as a lunchbox for the developing embryo. It delivers nutrients to the soon-to-be chick to help it grow.

My fellow interns (from left to right) Tori, Sabrina, Kalee, and Sabrina. They all successfully completed the process of opening up a chicken egg. Using posters that were created by Dr. Jensen and posted in the lab, we were able to determine what stage our eggs were in. When we finished, we all gave our chicken eggs a name.

My fellow interns (from left to right) Tori, Sabrina, Kalee, and Sabrina. They all successfully completed the process of opening up a chicken egg. Using posters that were created by Dr. Jensen and posted in the lab, we were able to determine what stage our eggs were in. When we finished, we all gave our chicken eggs a name.

Samantha, Photography Team
Week Four, Winter Session 2014

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