Type of Document Master's Thesis Author Blevins, Sarah URN etd-08172009-214911 Title Characterizing Compensatory Effects of Silymarin on Gossypol Toxicosis in Lines of Chickens Divergently Selected for Humoral Immune Response Degree Master of Science Department Animal and Poultry Sciences Advisory Committee
Advisor Name Title Lewis, Ronald M. Committee Chair Blodgett, Dennis J. Committee Member Ehrich, Marion F. Committee Member Siegel, Paul B. Committee Member Keywords
- Humoral Immunity
Date of Defense 2009-08-04 Availability unrestricted AbstractFeed costs are approximately 70% of total production cost for poultry producers.
Poultry diets in the United States generally consist of 2 grains: corn and soybean meal.
In recent years, the cost of these grains has dramatically increased. Due to these price
increases, producers seek alternative feeds that provide adequate nutrition, and are also
more affordable than “traditional” grains. Cottonseed meal is one alternative that is both
affordable and an excellent source of crude protein. However, cottonseed meal contains
gossypol, a pigment toxic to chickens.
This study had two main objectives. The first objective was to determine if
silymarin, an extract from milk thistle, could offset or prevent gossypol toxicosis. The
second objective was to determine if divergent selection for humoral immune response
would have an impact on the ability of the chicken to cope with gossypol toxicosis. Two
preliminary studies were conducted. One determined basal activities of liver
detoxification enzymes at various ages. The other determined concentrations of gossypol
and silymarin that should be added to the diet to elicit a response. The information
gathered from the second preliminary study was used to conduct the final experiment.
In the final experiment, chickens from each of 2 lines selected for humoral
immunity were exposed to diets containing gossypol, silymarin, gossypol and silymarin,
and a control. Humoral immunity had no impact on the ability of the chicken to cope
with gossypol toxicosis. Silymarin did not alleviate gossypol toxicosis. Future studies
will focus on using a lower gossypol concentration in the diet.
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