Starvation-induced alterations in hepatic lysine metabolism in different families of rainbow trout (Oncorhynchus mykiss)

Abstract

Starvation Induced Alterations in Hepatic Lysine Metabolism in Different Families of Rainbow Trout (Oncorhynchus mykiss) Angela Higgins This study focused on lysine catabolism by the lysine α-ketoglutarate reductase (LKR) pathway in rainbow trout (RBT). Selective breeding based on feed efficiency in 2 strains (A and B) of RBT generated 2 families within each strain. Eight fish from each of the four families were randomly allotted to individual tanks. Fish were fed until satiation for 3 wks at which time four fish within each family were randomly selected for 2 wks of starvation. After the 2 wk starvation, all fish were harvested. Hepatic in-vitro LKR activity and lysine oxidation (LOX) were measured as was LKR mRNA abundance. Strain A exhibited a 55% reduction in LKR transcripts compared to strain B pooled across both feeding levels (P<0.01). LKR mRNA was decreased (P<0.01) in starved versus fed fish. No differences were detected for LKR activity and LOX between fed and starved fish, between strains or between families. LKR transcripts were positively correlated to weight gain (p<0.01). I'd like to thank Dr. Blemings for all his support and votes of confidence through the uncharted territory of real-time PCR and library screening. Thanks to all my committee members, Drs. Wilson, Panaccione and Rexroad for their time and guidance, Dr. Scott Gahr for showing me numerous lab techniques and assisting in my first library screening, Dr. Jeff Silverstein at the National Center for Cool and Coldwater Aquaculture, for collaborating with our lab and answering all my questions about fish genetics, Dr. Jianbo Yao for his excellent suggestions for improving my library construction, Dr. George Seidel for his superb statistical analysis, Juanita Engles for performing the lysine oxidation experiments, my fellow graduate students, Beth Stinefelt and Aaron Keiss, and our work study, Erin Schenck.