A METABOLOMIC ASSESSMENT OF CULTURED COBIA HEALTH IN RESPONSE TO DIETARY MANIPULATION
Tracey B. Schock1, Sarah E. Newton2, John Leffler3, and Daniel W. Bearden1
1. National Institute of Standards and Technology, Analytical Chemistry Division, Hollings Marine Laboratory, Charleston, South Carolina
2. University of Arkansas Pine Bluff, NOAA EPP Scholar
3. Marine Resources Research Institute, South Carolina Department of Natural Resources, Charleston, SC 29412
Aquaculture produces a significant source of protein for global human consumption. In February 2008, U.S. government agencies, the National Oceanic and Atmospheric Administration (NOAA) and the National Institute of Standards and Technology (NIST), sponsored a workshop to identify issues and technologies that are deemed necessary to enhance the U.S. aquaculture industry’s competitiveness. A priority objective resulting from the workshop was to evaluate the ability to improve human health attributes of farmed fish products through dietary manipulation. Commercial fish diets rely heavily on fish meal and fish oil, which can be costly. Alternative protein and lipid sources may provide nutritionally improved high performance growth and improved cost effectiveness. To address these concerns, a dietary study was conducted by the South Carolina Department of Natural Resources (SCDNR) on the finfish cobia, Rachycentron canadum. Juvenile cobia were raised on four different diets: a commericial diet (control), a diet with conventional levels of fish meal (FM100), a diet with a 50% reduction in fish meal (FM50), and a diet with 25% reduced fish meal (FM25). The experimental diets substituted varying amounts of soybean meal and poultry meal for fish meal. A total of 432 fish were stocked in 24 tanks (6 tanks/diet) in three recirculating aquaculture systems. Seventy-two fish (3 fish/tank) were sampled on Day 0, Day 66, and Day 98. Physical growth measurements were taken and serum was sampled prior to filet and organ collection for metabolomic analysis. In the current study, we examined cobia sera with NMR-based metabolomic techniques to assess the affect of decreasing dietary fish meal on the health of the cobia. Filtered sera 1H NMR spectra were analyzed by principal components analysis (PCA). Cobia fed reduced fish meal diets were metabolically different than control and FM100 diets in PC1. Tyrosine and betaine increased in cobia fed reduced fish meal diets, while glucose decreased. This data suggests that the cobia on lacking fish protein were in a state of malnutrition. Growth performance measurements on Day 98 corroborate this data with control and FM100 fed cobia weighing significantly more than the FM50 and FM25 fed cobia. The results show that metabolomic analysis is useful for understanding the effects of alternative diets in aquaculture studies.