Thesis
Stress response and implications for white sturgeon (Acipenser transmontanus) cultivation: qualitative differentiation of soft and hard caviar and cortisol detection
Washington State University
Master of Science (MS), Washington State University
2011
Handle:
https://hdl.handle.net/2376/100774
Abstract
White sturgeon (Acipenser transmontanus) are frequently exposed to stress under aquaculture conditions. Practices that are common in aquaculture include: high stocking densities, handling, confinement, transportation, water temperature and pollution. All these stressful management practices can affect reproduction. Cortisol is one of the major “stress-related” hormones and its increased plasma levels have often been determined to indicate short term responses to stress. Here, white sturgeon (Acipenser transmontanus) caviar and roe were studied to test the hypothesis that stress, as reflected by cortisol levels, affect egg quality, making them soft. Cortisol levels were predicted using infrared spectroscopy and correlated with softening in sturgeon roe and caviar. Scanning Electron Microscopy (SEM) was used to examine any differences in envelope layers in roe and caviar. Linear models were constructed using singular value decomposition (SVD) from the training data. These linear models were used to predict hardness of caviar from the tasting spectra. Results indicated that FTIR spectral features could be correlated with hardness of sturgeon caviar with accuracy of 80-90%. Additionally, correlation between spectral features, cortisol signature, and caviar hardness was also found. Founding from SEM indicated extra layers in envelope layer in the sturgeon egg. Eggs rated to be soft had thicker envelope compared to eggs rated hard. Average envelope thicknesses were 51.6µm, 64.8µm and 70.8µm for hardness of 3,4,5 of 5 point scale respectively which suggests that softer eggs have thicker envelopes. The results indicated that there are bio-markers for hardness in caviar, but we cannot determine if there is a cortisol connection.
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Details
- Title
- Stress response and implications for white sturgeon (Acipenser transmontanus) cultivation
- Creators
- Beata Vixie
- Contributors
- Barbara Rasco (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Food Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; Pullman, Wash. :
- Identifiers
- 99900525005701842
- Language
- English
- Resource Type
- Thesis