EVALAUTION OF SOY PROTEIN'S EFFECTS ON LIPID METABOLISM THROUGH TARGETED QUANTITATIVE PCR IN JUVENILE RED DRUM, Sciaenops ocellatus

Two 12 week feeding trials were conducted to evaluate graded levels of fish meal replacement with soybean meal (SBM). In the first trial, brain, liver, and intestine samples were taken from experimental diets of a 0% SBM treatment and a 60% SBM treatment. RNA was isolated and sequenced on a HiSeq and subsequent transcriptomes were assembled with sequences identified by NCBI BLAST. By comparing transcript abundances and metabolic roles in tissues from each treatment (Figure 1), eight genes were identified as potential biomarkers indicative of a nutritionally derived physiological state with a strong effect on lipid metabolism.

The second feeding trial was conducted to evaluate four commercially available soy protein products at high inclusion levels. Four tanks of 35 fish were raised on each diet, as well as the 60% soybean meal diet from the first trial, and a natural diet as a positive control. Liver samples were taken in weeks 0, 2-5, and 9-12 for q-PCR assays to assess expression levels of the biomarker genes in determining the physiological state of the fish in comparison to the known performance trajectories developed in the first trial. Although no significant differences were observed in growth or feed consumption in the second trial, the NMR and qPCR profiles may indicate similar performance trends to the first trial, where a negative effect of increasing soybean meal inclusion was observed.