Agricultural run-off is one of the leading sources of environmental pollution in the United States. One major pollutant within this is insecticides, and among these, neonicotinoids which have become the most used insecticide class across the world. Neonicotinoids act as an agonist on the nicotinic acetylcholine receptor (nAChR) in the central nervous system of insects. Neonicotinoids are perceived to have low toxicity on non-target organisms however recently extensive literature has been published showing various effects on non-target organisms. Clothianidin is one of the most applied compounds belonging to the neonicotinoid class, yet few studies have investigated its chronic effects on fishes. In the Midwest, one species that is at particular risk of exposure is rainbow trout (Oncorhynchus mykiss) as their habitats are often intertwined with agricultural practices. This study aimed to expose developing rainbow trout (15-100 days post fertilization) to chronic environmentally relevant concentrations of Clothianidin (0, 0.3, 3, 30 μg/L) and analyze the effects on gross spinal abnormality development, swimming performance, behavior, and kidney and muscle histology. Gross spinal abnormality development was analyzed upon mortality of individuals before 72 dpf. At 72 dpf, rainbow trout were randomly selected and euthanized for histological analysis, Swimming performance was conducted on individuals aged 72-93 days post fertilization (dpf), followed by behavioral analysis (97-100 dpf). The current study found that in the highest concentration group, swimming performance significantly decreased, and development of gross spinal abnormalities significantly increased compared to the control. Clothianidin exposure also caused a significant decrease in myofiber size in the lowest and highest concentration group and a significant increase in intermyofiber distance in the two highest concentration groups compared to the control. Chronic Clothianidin exposure did not alter behavior or kidney development. These data were mixed with similar studies which show the varying effects that Clothianidin has on nontarget organisms based on procedural methods, species, life stage, and concentration and duration of exposure.
Date of Degree
Master of Science (MS)
Program of Study
Science, Engineering and Technology
Schmid, Jacob. (2023). Effects of Chronic Clothianidin Exposure on Various Aspects of Oncorhynchus mykiss (rainbow trout) Development [Master’s thesis, Minnesota State University, Mankato]. Cornerstone: A Collection of Scholarly and Creative Works for Minnesota State University, Mankato. https://cornerstone.lib.mnsu.edu/etds/1389/
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