Semester

Summer

Date of Graduation

2020

Document Type

Dissertation

Degree Type

PhD

College

Davis College of Agriculture, Natural Resources and Design

Department

Animal and Nutritional Sciences

Committee Chair

Janet Tou

Committee Member

Vagner Benedito

Committee Member

Joseph Gigliotti

Committee Member

Kristen Matak

Abstract

Fishery resources are currently operating either near optimal yield or at levels with elevated risk for fish stock depletion. A solution for overcoming limitations of natural fish resources is through utilization of less desirable fish species and fish processing by-products. Water-soluble sarcoplasm proteins consist of 25 – 30% of protein in carp, are lost in wash water during processing and can be recovered and freeze-dried to produce a protein-rich powder (CSP). The objective of this project was to evaluate the protein quality and safety of CSP, assess diets consisting of CSP or commercial milk proteins effects on lipid metabolism, and to investigate distinct phenotypic and hepatic transcriptome responses to CSP, casein, and whey protein using a growing animal model. Results showed greater (p < 0.05) fecal amino acid excretion in casein-fed rats, but no significant differences in liver and muscle amino acid profiles among protein diets. All low protein diets supported growth within the normal range, but whey protein-fed rats had greater (p < 0.05) adiposity. In the liver, rats fed protein-free diet had the highest (p < 0.05) total hepatic lipid content and highest histological evidence of hepatocyte fat infiltration. Rats consuming CSP showed no differences in hepatic weight, fat infiltration, and lipid metabolism biomarkers compared to casein and whey-fed rats. RNA sequencing of hepatic tissue was performed to further investigate. Consumption of protein-free diet resulted in the greatest number (1,814) of differentially expressed genes compared to casein diet. Collectively, results indicate protein quality of CSP is comparable to casein.

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