Transcriptome and Fatty Acid Analysis of Florida Pompano (Trachinotus carolinus) cultured at different salinities

Authors: BRADSHAW II, DAVID - Harbor Branch Oceanographic Institute; KING, LAURA - Harbor Branch Oceanographic Institute; MCHENRY, BRANDON - Harbor Branch Oceanographic Institute; URIBE, VICTORIA - Harbor Branch Oceanographic Institute; KIRCHHOFF, NICOLE - Live Advantage Bait, Llc; PERRICONE, CARLIE - Harbor Branch Oceanographic Institute; RICHE, MARTIN - Harbor Branch Oceanographic Institute; MEJRI, SAHAR - Harbor Branch Oceanographic Institute; SEPÚLVEDA, MARIA - Purdue University; WILLS, PAUL - Harbor Branch Oceanographic Institute; RUPNIK, BRENT - Live Advantage Bait, Llc

Submitted to: Aquaculture America Conference
Publication Type: Abstract Only
Publication Acceptance Date: 2/20/2021
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: A major economic impediment to the aquaculture of marine finfish in land-based recirculating systems is maintaining the system salinity at a range for optimal growth. Florida Pompano (Trachinotus carolinus) are warm water, euryhaline, marine finfish shown to be a suitable candidate for low-salinity culture. Due to its popularity among sport and commercial fishers, high market value, and ability to readily consume pelleted feeds, the Florida Pompano has become a renewed target for commercialized aquaculture. Although the Florida Pompano has been successfully grown at various salinities, its optimal growth salinity has not yet been established. Studies have shown culturing at different salinities has an effect on digestion rates, feed utilization, and lipid biosynthesis. Identifying the optimal salinity for growth would result in decreased energy expenditure on maintaining homeostasis, since osmoregulation is a highly demanding process. This would allow for energy to be spent on the efficient use of nutrients. Our study was designed to determine how Florida Pompano larviculture at various salinities affects fish health with transcriptomics (RNA-seq) and fatty acid analysis. RNA-seq was used to identify genes actively transcribed and expressed at the time of sampling. After hatching in a salinity of ~ 30 ppt, larvae were reared in 345 L tanks at one of three salinities (10, 20, 30 ppt) in triplicate. Larvae samples for RNA-seq and fatty acid analysis were collected every three days until weaning. Samples for fatty acid composition were analyzed using a gas chromatography-mass spectrometry (GC/MS). RNA was extracted from homogenized whole-body samples using the Qiagen RNeasy Mini kit. Total RNA was sequenced on the Illumina HiSeq 2500 System. Raw sequences were filtered for low-quality sequences, aligned to a draft Florida Pompano genome, and quantified. Each sampling day was compared across salinities to establish the differentially expressed genes (DEGs) between salinities. These DEGs were functionally annotated to explore the functions that were different between salinities. We hypothesized that an upregulation of expression of osmoregulation genes would occur in fish not reared at their optimal salinity. These genes include those associated with ion exchange, extracellular matrix remodeling, and general stress. Exploring correlations between expressed genes and fatty acids may help highlight novel associations between un-annotated genes and fatty acid expression, which would provide targets for future research. By understanding the differential expression of fatty acid genes at specific salinities and developmental milestones, diets can be optimized to supply the lipids essential for all life stages. This study will help enable the optimization of Florida Pompano larviculture using information on the optimal salinity and fatty acid content for growth and facilitate more cost-effective rearing methods.