METABOLOMICS ANALYSIS OF EFFECTS OF FEEDS WITH VARYING SOY CONCENTRATION IN RED DRUM (SCIAENOPS OCELLATUS)
Unique biochemical and physiological insight into the effects of different dietary regimes can be discovered through the use of metabolomics analysis. In metabolomics, small-molecule metabolites that comprise the metabolome are measured in tissues, biofluids or whole body samples using analytical techniques such as nuclear magnetic resonance (NMR). The effect that various feeds have on the fish metabolome can affect the physiological status of the individuals, both in a transitory manner and in a longer-term health status manner. This information may lead to better feed formulations for fish growth or resiliancy1.
In this study, we have used nuclear magnetic resonance (NMR)-based metabolomics protocols to assess the response of juvenile red drum (Sciaenops ocellatus) (initial weight: 45 g) to experimental diets with varying levels of soy protein, ranging from 0% soybean meal up to 60% soybean meal. The experiment design included 5 experimental diets, plus a commercial pelleted feed for standardization in an indoor recirculating aquaculture seawater system (twenty-four 1,600 L tanks with sand filters). Individual fish were sampled weekly for 12 weeks with collection of plasma, muscle, liver and intestine, using a robust collection protocol suitable for these types of studies. Six fish were sampled from each tank (n=6). Nearly 2,000 samples were analyzed, along with quality control samples, using NMR-based metabolomics for this time course study.
Mild, but statistically significant effects in feed consumption, weight gain and final weight were observed. However, the time course of the metabolome showed that the adjustment to new diets was progressive with stabilization of the metabolome in the 9 to 12 week time frame. In addition, even with mild differences in classical measures, the metabolomic fingerprints showed that the diets placed the fish in clearly distinguishable metabolomic states. The detailed analysis of the metabolites that lead to these differences shows the impact of the diet on metabolic pathways, leading to potential improvements in feed formulations.
1. (a) Schock, T. B.; Newton, S.; Brenkert, K.; Leffler, J.; Bearden, D. W., An NMR-based metabolomic assessment of cultured cobia health in response to dietary manipulation. Food Chemistry 2012, 133 (1), 90-101; (b) Schock, T. B.; Duke, J.; Goodson, A.; Weldon, D.; Brunson, J.; Leffler, J. W.; Bearden, D. W., Evaluation of Pacific White Shrimp (Litopenaeus vannamei) Health during a Superintensive Aquaculture Growout Using NMR-Based Metabolomics. PLoS ONE 2013, 8 (3), e59521. (c) Simpson, M. J, and Bearden, D.W. : "Environmental Metabolomics: NMR Techniques", eMagRes, Vol 2: 549-560. DOI 10.1002/9780470034590.emrstm1352, (2013).