Changes in musculoskeletal structure and function associated with domestication in the turkey

Stover, Kristin

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Year:: 2017
Contributor:: Stover, Kristin (creator); Brainerd, Elizabeth (Advisor); Roberts, Thomas (Advisor); Gatesy, Stephen (Reader); Weinreich, Daniel (Reader); Brown University. Biology and Medicine: Ecological and Evolutionary Biology (sponsor)
Genre:: theses
Subject:: Bones--Growth; Domestication; Muscles; Musculoskeletal system; Animal locomotion; Allometry; Turkeys
Extent:: 18, 115 p.
DOI: https://doi.org/10.26300/ssqg-fe70

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Abstract:: Domestic species are an example of experimental evolution involving intentional selective breeding for particular traits. These species provide an opportunity to study varying rates of trait evolution, exaggerated phenotypes, and their potential tradeoffs with functionality. In particular, domestic turkeys have been selectively bred for high growth rate and increased muscle mass. It is unclear how artificial selection for meat production has affected the musculoskeletal system as a whole in these birds and what impact it has had on muscle performance and locomotor function. A multi-level, comparative approach was taken to investigate the structural and functional changes associated with domestication in the turkey. To characterize the morphological changes we used a combination of dissection, CT scans throughout ontogeny, biplanar x-ray and SEM imaging to compare wild and domestic turkey strains. I found that the pectoralis muscle mass of the domestic turkeys was 2.8 times that of their wild counterparts, leading to a more anterior center of mass position. Individual muscle mass was increased by increasing the number of muscle fibers, rather than size of the individual fibers. While the domestic turkey’s hind limb bones did not increase much in length, their polar moment of area, a measure of torsional strength, did increase with body mass. These results indicate that domestic turkeys are not simply an isometrically scaled up version of a wild turkey, and that both selection and developmental plasticity play a role in the musculoskeletal morphology of the domestic turkey. Additionally, I compared locomotor function and contractile mechanics of an individual muscle between turkey strains. The domestic turkey displayed a distinct gait from wild turkeys that included slow speeds, relatively low ground reaction forces, increased stride frequency and large lateral oscillations, similar to a shuffling gait seen in some human populations. Individual muscle performance differed in maximum contractile velocity, indicative of a shift in fiber type composition, and in force production per unit body mass, a scaling limitation in the large domestic turkeys. I conclude that artificial selection on structural traits in the domestic turkey has also had a major affect on the function of the musculoskeletal system.
Notes:: Thesis (Ph. D.)--Brown University, 2017

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Rights: In Copyright
Restrictions on Use: Collection is open for research.

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Stover, Kristin, "Changes in musculoskeletal structure and function associated with domestication in the turkey" (2017). Ecological and Evolutionary Biology Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.26300/ssqg-fe70

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Ecological and Evolutionary Biology Theses and Dissertations

Theses and Dissertations for the Ecological and Evolutionary Biology department.
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