Project Proposal: Recommendation of an Alternative Fish Species
to be Used for 17β-estradiol Experiments in
Fish Reproduction Laboratories
Author: Elissa Dodson
Time Period: 7 weeks
University of Idaho
Department of Biology, Fish Reproduction Labs
Date: October 09, 2006
With the acceptance of this proposal an alternative laboratory fish species will be recommended for experiments that fish reproduction scientists need to conduct. Fish reproduction scientists need to investigate the effects of 17β-estradiol (the female sex
hormone) on male Rainbow Trout and several generations of their offspring. Due to the difficulties of conducting multigenerational experiments on Rainbow Trout, an alternative species is needed to act as a model fish for these experiments. In my final report I will present my recommendation of the ideal species to use and describe the necessary care techniques needed to raise and breed this species.
Rainbow Trout (Oncorhynchus mykiss) are the most widespread trout in the state of
Idaho and occur naturally in most major drainages. This species has had extensive commercial impact, being introduced to at least 45 countries for food or sport (Root 1994). Over the past several years the health and reproductive rate of Rainbow Trout has been threatened by chemicals being released from industrial and agricultural sources. It has become evident that a large number of these industrial and agricultural chemicals are estrogenic, and that some of these chemicals are widespread aquatic pollutants (Jobling et al. 1996). Estrogen is known as the female sex hormone, and is responsible for the development of female secondary sex characteristics. It has been shown in a variety of experiments that some prenatally male salmonids (the family that Rainbow Trout belong to), when exposed to a certain dosage of estrogenic chemicals, can develop as
physiological females (Afonso et al., 2002). Many sources suggest that these estrogenic chemicals can also lead to health defects in humans (Pryor).
17β-estradiol is the natural form of the female sex hormone that represents the estrogen derivative in humans. It has critical impact on reproductive and sexual functioning, interfering with the normal functioning of estrogen in the body (Stavroudis 1995). It has been shown to affect a number of fish by feminizing the males and disrupting egg production (Patyna 1999). As research on this topic continues, scientists now want to conduct experiments studying the effect that 17β-estradiol has on male
Rainbow Trout over successive generations. Unfortunately, Rainbow Trout have a lifespan of 6-8 years and are not sexually mature until 1-5 years, making it difficult to raise and breed several generations of Rainbow Trout in a laboratory setting. In response to this obstacle it has been proposed that an alternative fish species be chosen to conduct experiments on.
Three species of fish are commonly used in laboratories as model species for other fish. All of these species have previously been used in similar experiments involving the effects of estrogenic chemicals. These model species include the Fathead Minnow (Pimephales promelas), the Zebra Fish (Danio rerio), and the Japanese Medaka
(Oryzias latipes). In the final report these species will be investigated and one of them will be chosen as the ideal model fish for the multigenerational 17β-estradiol experiments.
A large number of industrial and agricultural chemicals are becoming widespread aquatic pollutants. One of these chemicals is estrogen, the female sex hormone. This chemical has been known to cause prenatally male fish to develop female secondary characteristics and disrupt egg production. Researchers involved in the fish reproduction field want an investigation on the effects of 17β-estradiol, the natural form of estrogen, on male
Rainbow Trout and their offspring. Due to the long lifespan of Rainbow Trout, it is impractical to do multigenerational research on these fish. This creates a need for an alternative fish species for laboratory experiments.
The primary objectives of this project are:
1. To conduct secondary research in order to find an alternative fish species to
use instead of Rainbow Trout in the proposed multigenerational 17β-estradiol
2. To conduct secondary research in order to discover the necessary care
techniques needed to raise and breed these fish in a small laboratory.
3. To turn in a final report that presents the ideal alternative fish species, and
also includes the necessary information about raising and breeding this species.
This information will then be used by primary researchers to actually conduct
Secondary research will be conducted in order to accomplish the main objective of this project. The majority of this research will be obtained from peer reviewed scientific journal articles. These articles will provide information on Rainbow Trout life history, the known effects of estradiol, and relevant experiments that have been previously conducted on alternative laboratory fish species. The possible species will be evaluated using length of lifespan, age of maturation, ease of handling, and general knowledge of the species and the ideal fish species will be identified based on these comparisons. When the alternative fish species is chosen I will also research the raising and breeding techniques needed using manuals provided by pet stores and researchers.
Oct Oct 23-Nov Nov
9-19 Oct 20 Nov 2 Nov 3 6-24 13 Dec 6
Secondary Research X X
Progress Report X
Write section of Final Report X
Submit section of Final Report X
Write Final Report X
Oral Report X
Submit Final Report X
Name Title Rate Number of Hours Amount
Elissa Dodson Student Researcher $9.00 / hr 70 $630.00
Project Total $630.00
As a senior biology major at the University of Idaho, I have taken numerous relevant courses including General Ecology & Field Biology, Conservation Biology, and Organic Chemistry. As an undergraduate I have conducted several research projects and designed my own experiment involving zooplankton egg banks. Through this experience I have gained a strong understanding of how to successfully conduct secondary research on a variety of topics. These writing intensive biology classes and projects have also given me experience in learning how to properly write final reports and incorporate secondary research into the text. With this experience and knowledge I am competent to conduct the secondary research required in this project, and to present the resulting information in a comprehensive final report.
As more industries increase the flow of estrogenic chemicals into the environment, it becomes essential to know how these chemicals are affecting the ecosystems that are exposed to them. Fish are especially vulnerable to these pollutants and can act as models for how the chemicals could affect humans.
Due to their popularity for food and game, many researchers are focusing on how Rainbow Trout are affected by 17β-estradiol. Because 17β-estradiol is the natural
analogue of estrogen it has been chosen as the experimental chemical. Previous studies have already shown that this chemical has tendencies to turn prenatally male fish into physiological females and to affect egg production. Studies are now needed to investigate how many generations these affects can be passed onto. Since rainbow trout have such long lifespans, an alternative fish species needs to be found that is better suited
for lab experiments. The problem is to find the ideal fish species to use. When this proposal is approved, I will provide a recommendation of alternative fish species backed by thorough secondary research. Researchers will then be able to take this recommendation and implement it into actual experiments. The results from these experiments can then be used to affect industry regulations to promote a safer environment for both fish and humans. By approving this proposal you will be aiding the gain of information necessary to improve the quality of the ecosystems that surround us.
Afonso, L.O.B., Smith, J.L., Ikonomou, M.G. and Devlin, R.H. 2002. Y-chromosomal DNA markers for discrimination of chemical substance and effluent effects on sexual differentiation in salmon. Environmental Health Perspectives
Jobling, S., Sheahan, D., Osborne, J.A., Matthiessen, P. and Sumpter, J.P. 1996. Inhibition of testicular growth in rainbow trout (oncorhynchus mykiss) exposed to
estrogenic aklkylphenolic chemicals. Environmental Toxicology and Chemistry, 15, 194-
Patyna, P.J., Davi, R.A., Parkerton, T.F., Brown, R.P. and Cooper, K.R. 1999. A proposed multigeneration protocol for Japanese medaka (Oryzias latipes) to evaluate
effects of endocrine disruptors. The Science of the Total Environment, 233 pp. 211-220
Pryor, K. Environmental estrogens: The invisible threat that surrounds us. Vitamin Research News 02 October 2006. <http://www.vrp.com/art/417.asp>
Root, Laurie. 1994. Rainbow Trout (Oncorhynchus mykiss). S.D. Department Game,
http://www.northern.edu/natsource/FISH/Rainbo1.htm> Fish and Parks. 5 October 2006. <
Stavroudis, Chris. Jan 1995. Health and Safety: The Topic is Estrogenic Chemicals. WAAC Newsletter, 17 (1). Pp. 9