Never Fear, Chickens Are Here!

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 jobs, and then blog about their experience online.  Follow their adventures here on the Zoo’s website!

kalee_week4_picTom Jensen is attempting to save kiwis… with the help of chickens.

Dr. Jensen works at the San Diego Zoo Institute for Conservation Research as a research scientist. Originally from Denmark, he has made his love of birds well known here in California by doing all he can to help preserve his beloved avian friends. Dr. Jensen is currently working on the kiwi project. This project involves researching the causes for the species decline, the biological make up of the animal, and new methods of breeding the kiwis. Kiwis are an endangered species indigenous to New Zealand and, not surprisingly, look very similar to the fruit that shares their name, minus the neck, head, and leg bits of course. The causes for their dangerously low population include habitat loss and predation by non-native animals such as ferrets, dogs, and cats. The non-native predation that kiwis are experiencing is especially harmful because New Zealand is an island, which mean that the kiwi populations s under threat cannot migrate out of harms way. Luckily, Dr. Jensen and his chicken sidekicks are making their way towards saving these endangered birds.

Dr. Jensen explained that since a kiwi can only lay one large egg at a time, reproduction is a slow process. Also, it is too often the case that a breeding pair just does not produce an egg. When a species is rapidly becoming extinct, a slow reproduction rate can be detrimental to their chances of survival. To help the kiwi, Dr. Jensen is investigating the use of stem cells to increase the reproductive potential of these birds. He produces male kiwi reproductive cells (sperm) with the help of chicken eggs. First, he gathers stem cells from a kiwi (these cells can be obtained from blood). He then grows the stem cells in a culture, which usually consists of food for the cells and a medium or solution.
Once the stem cells have been cultured, they can be injected into a blood vessel inside of the chicken egg. To do this, the eggshell is sanded just enough to expose the membrane. (If you cannot visualize the membrane, just think of that thin, clear layer under the shell when you try to peel a boiled egg.) The stem cells are injected using a needle with a microscopically small tip. The egg is illuminated from the sides with high-power lights and if you look closely enough, you can see the tiny, partly formed heart beating.

Following this process, known as xenotransfer, the egg is placed back into the incubator to develop. These male chickens, when developed, should theoretically produce both kiwi and chicken sperm. The kiwi sperm are genetically “tagged” with a color marker, so that scientists can collect only the sperm they want. Once the sperm is collected, it could be used to artificially inseminate a kiwi ova, or egg. Then…. TADA! A baby kiwi would, hopefully, be born!

By making kiwis from chickens, Dr. Jensen hopes to preserve this exotic species by increasing the reproductive lifespan of genetically valuable individuals. His research will ultimately increase breeding success and enhance the genetic variation of kiwi populations in captivity, which will act as a safeguard against extinction. Genetic diversity is very important! If a species only has a few individuals left, many of these individuals might be closely related. When related animals breed with each other, it can result in genetically weaker offspring as a result of prone to genetic mutations. This that could make them less adequately adapted to the environment. Inbreeding can also increase the risk of genetic disease.

Why go to all this trouble? What does this research accomplish? As wildlife populations around the world continue to decline, science has the potential to help rescue endangered species. Dr. Jensen’s research is the cutting edge of conservation efforts. With the development of these new techniques, there is hope for kiwis. Further, Dr. Jensen and his team will be able to use the knowledge gained from the kiwi project and expand it to contribute to the breeding success of other endangered birds. As these techniques are refined, other research institutions and conservation organizations can look to their techniques as a model to solve their own reproductive challenges.

Kiwis are important, not just because they are cute, but because they are intertwined into the ecosystems that we share. In saving an endangered species, we are also preserving diversity and, in turn, saving the environment that we depend on. Every animal plays a role in sustaining the environment they inhabit. Kiwis are seed dispersers and help to control insect population. Without kiwis, New Zealand’s native ecosystems could collapse. The loss of just one species can cause, an entire ecosystem to suffer. As humans, we have a large roll to play in conserving both individual species and the ecosystems habitats is in which they live.

Kalee, Conservation Team
Week Four, Winter Session 2014

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