Effect of starvation on global gene expression and proteolysis in rainbow trout (Oncorhynchus mykiss)

Abstract

Background: Fast, efficiently growing animals have increased protein synthesis and/or reduced protein degradation relative to slow, inefficiently growing animals. Consequently, minimizing the energetic cost of protein turnover is a strategic goal for enhancing animal growth. Characterization of gene expression profiles associated with protein turnover would allow us to identify genes that could potentially be used as molecular biomarkers to select for germplasm with improved protein accretion.

The Phenomics and Expression Quantitative Trait Locus Mapping of Brain Transcriptomes Regulating Adaptive Divergence in Lake Whitefish Species Pairs (Coregonus sp.)

“…eQTL of ribosomal protein genes (both 40S and 60S) were associated with two of these instances of overlap (on LG's 1m and 6m). Ribosomal proteins are integral components of the ribosome where they stabilize rRNA structure and regulate translocation of mRNA and tRNA, both of which are essential for optimal mRNA translation into protein (Melese and Xue 1995;Salem et al 2007). In much the same way that RNA-DNA ratios are commonly used to estimate growth and condition (Buckley et al 1999), we hypothesize that regulation of ribosomal protein genes is functionally related to growth rate and condition factor QTL through increased protein biosynthesis and turnover (Smith et al 2000).…”

Aspartic Cathepsin D Endopeptidase Contributes to Extracellular Digestion in Clawed Lobsters Homarus americanus and Homarus gammarus

“…6). This increase may reflect the physiological demand to digest protein on the first day after feeding, similar to aspartic proteinase genes in sea bass and rainbow trout (Salem et al 2007;Terova et al 2007). Regulation of digestive proteinases activity is achieved via transcriptional, post-transcriptional, and/or post-translational control.…”

Energy allocations to xenobiotic transport and biotransformation reactions in rainbow trout (Oncorhynchus mykiss) during energy intake restriction

“…Throughout their lifetime, teleost fish species can naturally experience periods of fasting and severely restricted energy intake during which body energy reserves are mobilized to meet a portion of energetic costs (Andersson et al 1985;Boujard et al 2000;Peragon et al 1999;Ruane et al 2002;Salem et al 2007). How energy partitioning in fish is affected when gross intake energy is reduced by change in diet quality or quantity is unknown, and is an area of active research pertinent to aquaculture as well as ecological and toxicological study (Azevedo et al 1998;Cho 1990, Furne et al 2008Lanno et al 1989).…”

“…Portioning within organisms may also be affected by factors which alter the availability of assimilated energy. Many teleost species annually undergo fasting and starvation periods during over-wintering, sexual maturation, and migration during which endogenous stores and body tissues are catabolized to meet energy demands (Andersson et al 1985;Peragon et al 1999;Boujard et al 2000;Ruane et al 2002;Salem et al 2007). In addition to natural periods of Contaminated aquatic habitats can harbor natural toxins as well as anthropogenic stressors which may degrade the quantity and quality of food they contain.…”

“…These results are in agreement with other literature on feed-deprived rainbow trout, in which BW decreased within 4 to 6 weeks, and reductions in LSI became significant within much shorter time frames (2 days to 3 weeks of dietary restriction) (Farbridge and Leatherland 1992;Vigano et al 1993;Blom et al 2001;Mattson et al 2001). The rapid change in LSI in early fasting is likely due to a cortisol-induced mobilization of liver glycogen and lipid stores; as trout fasted for 3 to 4 weeks exhibit enhanced gene expression of key enzymes in gluconeogenesis, and a down-regulation of glycolysis and the pentose phosphate pathways (Blom et al 2000;Simpkins and Hubert 2003;Johansen and Overturf 2006;Salem et al 2007). As the body adjusts to long-term fasting, visceral fat and muscle lipid stores begin to be catabolized for maintenance energy in preference to exhausting hepatic lipid stores; this can be exhibited as a resistance to further reductions in LSI that have been noted in past studies, and in the present study appears as little reduction in mean LSI of fasted fish after week 3 (Adams and McLean 1985;Farbridge and Leatherland 1992;Simpkins and Hubert 2003;Salem et al 2007).…”