Courtesy of Deena Scoville' 20

Scoville '20

January 21, 2019

Student Spotlight on Deena Scoville ’20: Researching the Persistency of Lay in Chickens

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With the world population set to grow by an estimated 25 percent over the course of the next four decades, the need to increase food production is becoming an increasingly pressing issue. In response, the egg production industry is prioritizing increasing production, especially as eggs are one of the most affordable sources of protein.

Deena Scoville ’20, an animal science major and education minor in the College of Agriculture and Life Sciences, is working towards understanding the variability in egg production amongst chickens.

Scoville has been studying the persistency of lay in chickens under the mentorship of Ph.D. student Laurie Fracoeur. “Egg laying chickens are typically only kept for one year because their egg production decreases significantly after one year,” Scoville said.

Scoville’s research aims to identify attributes of good egg layers that will have optimal egg production during their second year of lay. Egg production has been recorded daily and blood samples have been collected monthly for each bird. Her project has been ongoing since this past summer.

“Our lab focuses on ovarian follicle development in chickens at the molecular level and how it relates to the whole organism,” Scoville said. Follicle development is the process by which an ovarian follicle, a small sac of fluid which contains immature eggs, matures. Since chickens have short ovarian cycles, they make good models to study follicle development, Scoville said.

Scoville emphasized the presence of variability, noting that some chickens continue to lay eggs at high efficiencies past their first year, a phenomenon called “persistency of lay.”

“One of the project’s difficulties early on was collecting and getting a sufficient volume of blood from each bird,” Scoville said. Blood was drawn from the brachial vein, located between the biceps and triceps muscles of the wing.

“Another difficulty of drawing blood from chickens is that hematomas (swelling of clotted blood within the tissues) form easily, and once one forms, blood cannot be collected from that vein,” Scoville said. With more experience and practice, collecting the necessary blood volume from each bird has grown easier she said.

“This project is set to run till January of 2020. At the completion of this experiment, we plan to analyze egg production, hormone profiles and gene expression between high efficiency layers and low efficiency layers,” Scoville said. Layer efficiency will be determined by calculating the number of eggs laid by each bird in a given amount of time.

In order to potentially help correlate early levels of hormones in the hens with layer efficiency, they will measure hormone levels.

Scoville also hopes to identify differentially expressed genes between chickens of varying layer efficiency, using RNA sequencing. If a certain genetic marker could be identified that promotes a longer period of egg production, then chicken breeders could utilize this information when making decisions on which traits to select for the next generation.

“Hopefully, this will shed light on the ovarian factors which influence egg production in order to improve the economic value and sustainability of an already very efficient model,” Scoville said.