Untargeted metabolic profiling reveals distinct patterns of thermal sensitivity in two related notothenioids

Antarctic marine ectothermal animals may be affected more than temperate species by rising temperatures due to ongoing climate change. Their specialisation on stable cold temperatures makes them vulnerable to even small degrees of warming. Thus, addressing the impacts of warming on Antarctic organisms and identifying their potentially limited capacities to respond is of interest. The objective of the study was to determine changes in metabolite profiles related to temperature acclimation. In a long-term experiment adult fish of two Antarctic sister species Notothenia rossii and Notothenia coriiceps were acclimated to 0 °C and 5 °C for three months. Impacts and indicators of acclimation at the cellular level were determined from metabolite profiles quantified in gill tissue extracts using nuclear magnetic resonance (NMR) spectroscopy. Furthermore, the metabolite profiles of the two con-generic species were compared. NMR spectroscopy identified 37 metabolites that were present in each sample, but varied in their absolute concentration between species and between treatments. A decrease in amino acid levels indicated an increased amino acid catabolism after incubation to 5 °C. In addition, long term warming initiated shifts in organic osmolyte concentrations and modified membrane structure observed by altered levels of phospholipid compounds. Differences in the metabolite profile between the two notothenioid species can be related to their divergent lifestyles, especially their different rates of motor activity. Increased levels of the Krebs cycle intermediate succinate and a higher reduction of amino acid concentrations in warm-acclimated N. rossii showed that N. rossii is more affected by warming than N. coriiceps

Metabolite profiles of two Antarctic sister species (Notothenia rossii and Notothenia coriiceps) at different temperatures

Antarctic marine ectothermal animals may be affected more than temperate species by rising ocean water temperatures due to ongoing climate change. Their specialisation on stable cold temperatures make them vulnerable to even small degrees of warming. Thus, addressing the impacts of warming on Antarctic organisms and identifying their potentially limited capacities to respond is of particular interest. The objective of the study was to determine changes in metabolite profiles related to temperature exposure and acclimation. In a long-term experiment adult fish of two Antarctic sister species Notothenia rossii and Notothenia coriiceps were acclimated to 0 °C and 5 °C for three months. Impacts and indicators of acclimation at the cellular level were determined from metabolite profiles quantified in gill tissue extracts by using nuclear magnetic resonance (NMR) spectroscopy. Furthermore, the metabolite profiles of the two con-generic species were compared. NMR spectroscopy identified over 40 metabolites that were present in each sample, but varied in their absolute concentration between species and between treatments. Variations in the concentration of phospholipid compounds, amino acids and osmolytes suggested that warming caused changes in the cellular membrane structure. It also increased the catabolism of amino acids and initiated shifts in osmoregulation. Some differences in the metabolite profile between the two notothenioid species were related to their divergent lifestyles, especially their different rates of motor activity. Increased levels of the Krebs cycle intermediate succinate and falling amino acid levels in warm-acclimated N. rossii suggested that N. rossii is more sensitive to warming than N. coriiceps. Data are obtained from dried polar gill extracts, which were re-suspended in deuterated water (D2O) to a final concentration of 1 g frozen gill tissue/ml solvent. The D2O contained 0.05 wt.% of 3-(trimethylsilyl) propionic-2,2,3,3-d4 acid, sodium salt (TSP) (Sigma Aldrich, St. Louis, USA). TSP was used as chemical shift and quantification standard. For each sample 50 µl of the resuspended gill extracts were analysed

Lupin kernel meal as fishmeal replacement in formulated feeds for the Whiteleg Shrimp (Litopenaeus vannamei)

Rapidly expanding global aquaculture requires sustainable, local protein sources to supplement the use of fishmeal. Lupin seed meal (Lupinus angustifolius) was tested as sustainable diet component for Whiteleg shrimp (Litopenaeus vannamei). Controlled feeding experiments were conducted in a recirculating aquaculture system for eight weeks. Juvenile shrimps were provided formulated diets containing various levels of lupin meal inclusion (0, 100, 200 and 300 g kg−1) supplementing the fishmeal component, and a commercial feed as general reference. Shrimp survival, growth, metabolic and immune parameters were analysed. Survival did not differ significantly between groups. Growth performance was significantly impaired in shrimp fed diets containing more than 100 g kg−1 lupin meal. Lupin meal supplementation did not affect haemolymph protein content, whereas glucose and acylglyceride concentrations varied between treatments and were highest in animals fed the 100 g kg−1 lupin meal diet. Phenoloxidase activity was highest in shrimp fed 100 g kg−1 lupin meal diet indicating improved immune status. The present study indicates that low inclusion levels of lupin meal do not cause adverse effects and seem to stimulate the immune system of juvenile L. vannamei