Aquaculture produces a significant source of protein for global human consumption. Commercial fish diets rely heavily on fishmeal 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 fishmeal (FM100), a diet with a 50% reduction in fishmeal (FM50), and a diet with 25% of the conventional level of fishmeal (FM25). The experimental diets substituted varying amounts of soybean meal and poultry meal for fishmeal. A total of 432 fish were stocked in 24 1.4 m3 tanks (6 tanks/diet) in three recirculating aquaculture systems in a randomized block design. 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 effect of decreasing dietary fishmeal on the health of the cobia. Filtered sera 1H NMR spectra were analyzed by principal components analysis (PCA). Cobia fed reduced fishmeal diets (FM50/FM25) were metabolically different than Control and FM100 diets in PC1. In particular, tyrosine and betaine increased in cobia fed reduced fishmeal diets, while glucose decreased. These data suggest that the cobia lacking fish protein were not receiving the necessary nutritional components required for energy and growth. Over time lactate contributed to the enriched growth of the FM100 diets through endogenous lactic acid bacteria enhanced by dietary components (corn starch and reduced marine oil).
Citation: Food Chemistry
Pub Type: Journals
Aquaculture, Cobia, Diet, Fishmeal, NMR, Nuclear Magnetic Resonance, Metabolomics, Rachycentron canadum