Aquaculture Research Institute at University of Idaho in collaboration with USDA has genetically selected the several lines of rainbow trout (Oncorhynchus mykiss) that show higher growth rates when fed all plant protein diet (PPD) than non-selected lines of trout fed a fishmeal-based diet. We propose to test if feed intake and body weight variations during successive periods of feed deprivation (FD) and re-feeding (RF) are correlated using compensatory feeding regime and has examined the proteomics profile of these fish based on their feed efficiency phenotype during FD and RF periods.
We have used 1600 fish from 12 families of the selected trout lines, fed PPD (50% soy). Fish were tagged individually, reared in common environment, went through the first feeding challenge, alternate months of FD and RF for 4 months, and performance was recorded . Thereafter, fish were separated into four groups (1331 fish) based on individual performance during FD and RF challenge studies. Feed Conversion Ratio (FCR) was recorded for 3 months in all four groups followed by measuring the stability of response to the FD and RF periods (second feeding challenge) which was the same as the first one. Liver samples were collected after each month of the challenge and protein extraction and analysis were done down the line.
Figure 1: Heat map of the top twenty proteins from two-way ANOVA results using phenotype and sampling time.
The major goal of this study is to understand the underlying molecular mechanism on how some animal can conserve energy more efficiently compared to others and loose less weight over a feed deprivation period (FD-) and gain more weight over a re-feeding period (RF+). For that, a proteomics approach was taken to investigate such mechanisms at the protein level. We were able to detect ~3000 proteins in the liver tissue for each phenotype and as shown in our preliminary data in figure 1, there are multiple proteins with different responses to the feeding regimen identified in each group. A deep analysis of the results is ongoing and will be presented at the conference.