Effect of Transport Density on Greater Amberjack (Seriola dumerili) Stress, Metabolism, Antioxidant Capacity and Immunity

Abstract

This study sought to characterize the effect of density stress on greater amberjack (Seriola dumerili) survival to determine an optimal transport density. To achieve this, this experiment simulated the transport conditions of fish (body length: 4.09 ± 1.00 cm; weight: 0.9 ± 0.05 g) using closed oxygen transport at 5 different densities (D1 = 1.125 kg/m3, D2 = 2.25 kg/m3, D3 = 3.375 kg/m3, D4 = 4.5 kg/m3, and D5 = 6.75 kg/m3) for 8 hours, after which biochemical indicators, stress, metabolism, and antioxidant capacity were evaluated. After 8h, only the D1 and D3 groups exhibited survival rates above 90%. The pH of the water decreased with density, whereas the ammonia nitrogen and nitrite increased with density. Cortisol (COR) levels were not significantly different among all the groups, but tended to increase with increasing density. In this study, COR is a relatively stable index with the increase in density, but in D3 group, the change of COR will not cause the change of immune-related genes, so COR can inhibit the expression of immune genes within a certain density. The D3 density group exhibited the highest catalase (CAT) and glutathione peroxidase glutathione peroxidase (GSH‐PX) levels. In addition, the expression levels of immune related factor interleukin-1β (IL-1β), tumor necrosis factor (TNF-α), major histocompatibility complex (MHC-1) and nuclear factor kappa-B (NF-KB1) were the lowest in D3 density group. The density of fish during transportation significantly affects water quality, metabolism, and immunity. During transportation, assuming that the plastic bags are airtight to ensure aerobic conditions and that the transportation time is within 8 h, transport density should be maintained at approximately 3.375 kg/m3.

Alternative splicing plays a nonredundant role in greater amberjack (Seriola dumerili) in the adaptation to ambient salinity fluctuations

“…In our previous study, we sequenced the transcriptomes for two osmoregulatory tissues, gills and kidney, for greater amberjack juveniles reared under different salinity regimes: 10, 30 and 40 parts per thousand (ppt) (National Center for Biotechnology Information (NCBI) accession number: GSE220485) (Liu et al, 2023). Here, we re-used these RNA-seq data to investigate the role of AS regulations in greater amberjack in response to ambient salinity changes.…”

“…To further investigate the different roles between AS and gene expression in modulating salinity oscillation tolerance in greater amberjack, we compared the more exon-inclusive DSGs to the up-regulated differentially expressed genes (DEGs) under each treatment scenario. The DEGs were detected following the same criteria described in our previous study (Liu et al, 2023). GO enrichment analyses were then conducted for 1) the genes specifically regulated by differential AS (DS-specific genes), and 2) genes specifically regulated by differential expression (DE-specific genes).…”

“…Here, we re-used these RNA-seq data to investigate the role of AS regulations in greater amberjack in response to ambient salinity changes. Following the data preprocessing pipeline described in Liu et al (2023), adapter contamination and low-quality reads were filtered out using Trim Galore v. 0.6.6 (Krueger, 2012) with a quality score cut-off of 25 and a read-length threshold of 50 bp. A genome index was constructed for the reference genome of greater amberjack (NCBI GCA_002260705.1) by the hisat2-built utility of HISAT2 package v. 2.2.1 (Kim et al, 2019).…”

“…To access the functional importance of the DSGs, an OrgDb database was first built for greater amberjack using the R package AnnotationForge v. 1.38.1 (Carlson and Pages, 2017), based on the gene annotations obtained in our previous study (Liu et al, 2023). For both gills and kidney, Gene Ontology (GO) enrichment analysis was carried out for the DSGs via the enrichGO function of clusterProfiler package v. 4.6.2 (Wu et al, 2021).…”

“…2021; Lu et al, 2022;Lacy et al, 2023;Röthig et al, 2023). For example, the increased water salinity was found to disrupt the normal energy allocation, and physiological and metabolic processes of fish, such as grass carp (Ctenopharyngodon idella) and African catfish (Clarias gariepinus), and finally inhibit their growth and survival (Smyth and Elliott, 2016;Zidan et al, 2022;Liu et al, 2023). Moreover, salinity change-induced biodiversity loss of plankton, macroalgae, coral reef, and seagrass may cause trophic collapse of marine ecosystem and lead to drops in fishery yield, which threaten ecosystem functions and food supply to human (Röthig et al, 2023).…”