Location: Natural Products Utilization Research
2015 Annual Report
Objectives
Objective 1: Develop management strategies to mitigate pre-harvest microbial-derived off-flavors in fish cultured in recirculating aquaculture systems (RAS) to reduce off-flavor delayed harvest.
Objective 2: Discover and develop management strategies to mitigate pre-harvest microbial-derived off-flavors in fish cultured in outdoor earthen ponds to reduce off-flavor delayed harvest.
Sub-objective 2.A.: Evaluate and identify the impact of split-pond production practices in reducing or enhancing the incidences and intensities of common pre-harvest off-flavors in channel catfish.
Sub-objective 2.B.: Further evaluation of biofloc technology (BFT) production systems for the benefits in managing common pre-harvest off-flavors in cultured finfish.
Sub-objective 2.C.: Evaluation of a biocontrol approach in reducing the abundance of common off-flavor producing cyanobacteria in catfish production ponds.
Approach
Develop management strategies to mitigate pre-harvest microbial-derived off-flavors in fish cultured in recirculating aquaculture systems (RAS) to reduce off-flavor delayed harvest. Discover and develop management strategies to mitigate pre-harvest microbial-derived off-flavors in fish cultured in outdoor earthen ponds to reduce off-flavor delayed harvest. Evaluate and identify the impact of split-pond production practices in reducing or enhancing the incidences and intensities of common pre-harvest off-flavors in channel catfish. Further evaluation of biofloc technology (BFT) production systems for the benefits in managing common pre-harvest off-flavors in cultured finfish. Evaluation of a biocontrol approach in reducing the abundance of common off-flavor producing cyanobacteria in catfish production ponds.
Progress Report
A relatively new design of outdoor, earthern aquaculture ponds referred to as partitioned aquaculture systems (PAS) or split-ponds is growing in acceptance and is used by aquaculturists for the production of channel catfish in the southeastern United States. However, no previous research on the composition of phytoplankton communities and the occurrence and intensities of common off-flavors in catfish such as “earthy” and “musty” within PAS has been performed. Preliminary analysis of collected water and fish samples during the first year of a two-year study have determined that both earthy and musty off-flavors can occur in catfish raised in split-ponds, and these off-flavor episodes can mimic the intensities observed in commercial earthen ponds (non-partitioned).
In order to verify previous research, water and fillet samples collected from biofloc technology (BFT) systems used to culture channel catfish were analyzed for the presence and concentrations of common off-flavor (e.g., earthy-musty) compounds and to identify the potential microbial sources of the common off-flavors. The benefits of using BFT systems to culture channel catfish were further demonstrated by the observed significant reductions in the intensities of earthy-musty off-flavors in fish flesh during the production grow-out period as compared to catfish cultured in earthen ponds. While the microorganisms responsible for the earthy-musty compounds have not yet been identified, certain bacteria such as actinomycetes and planktonic cyanobacteria, which are associated with the production of earthy and musty compounds in recirculating aquaculture systems (RAS) and catfish aquaculture ponds, respectively, appear to be unlikely sources due to their very low abundance in the BFT systems.
Accomplishments
Review Publications
Green, B.W., Schrader, K., Perschbacher, P.W. 2014. Effect of stocking biomass on solids, phytoplankton communities, common off-flavors, and production parameters in a channel catfish biofloc technology production system. Aquaculture Research. 45(9):1442-1458.
Meepagala, K.M., Schrader, K. 2014. Antibacterial activity of acylglucinol derivatives against Flavobacterium columnare. Journal of Agricultural Chemistry and Environment. 3:89-95.
Tan, C.-X, Schrader, K.K., Khan, I.A., Rimando, A.M. 2015. Activities of wogonin analogs and other flavones against Flavobacterium columnare. Chemistry and Biodiversity. 2015;12:259-272.
Green, B.W., Schrader, K.K. 2015. Effect of stocking large channel catfish in a biofloc technology production system on production and incidence of common microbial off-flavor compounds. Journal of Aquaculture Research and Development. 6:314. Available:http://dx.doi.org/10.4172/2155-9546.1000314
Schrader, K., Harries, M.D., Page, P. 2015. Temperature effects on biomass, geosmin, and 2-methylisoborneol production and cellular activity by Nocardia spp. and Streptomyces spp. isolated from rainbow trout recirculating aquaculture systems. Journal of Industrial Microbiology and Biotechnology. 42:759-767.
