Metabolic and immune responses of Chinook salmon (Oncorhynchus tshawytscha) smolts to a short‐term poly (I:C) challenge

Abstract

Polyinosinic:polycytidylic acid [poly (I:C)] was administered in vivo to Chinook salmon (Oncorhynchus tshawytscha) post‐smolts to determine the immune responses on haematological and cellular functional parameters, including spleen (SP), head kidney (HK) and red blood cell (RBC) cytokine expression, as well as serum metabolomics. Poly (I:C) in vivo (24 h exposure) did not affect fish haematological parameters, leucocyte phagocytic activity and phagocytic index, reactive oxygen species and nitric oxide production. Gas chromatography–mass spectrometry–based metabolomics revealed that poly (I:C) significantly altered the serum biochemistry profile of 25 metabolites. Metabolites involved in the branched‐chain amino acid/glutathione and transsulphuration pathways and phospholipid metabolism accumulated in poly (I:C)–treated fish, whereas those involved in the glycolytic and energy metabolism pathways were downregulated. At cytokine transcript level, poly (I:C) induced a significant upregulation of antiviral ifnγ in HK and Mx1 protein in HK, SP and RBCs. This study provides evidence for poly (I:C)–induced, immune‐related biomarkers at metabolic and molecular levels in farmed O. tshawytscha in vivo. These findings provide insights into short‐term effects of poly (I:C) at haematological, innate and adaptive immunity and metabolic levels, setting the stage for future studies.

Haematological and metabolic profiles associated with age and sex in giant kokopu (Galaxias argenteus) (Gmelin 1789) broodstock

“…Furthermore, liver levels of NEAA, 1‐aminocyclopropane‐1‐carboxylic acid and serine were co‐influenced by age and sex. The authors recently detected 1‐aminocyclopropane‐1‐carboxylic acid in fish serum (Lulijwa et al ., 2020). Its physiological importance currently remains unresolved in fish.…”

“…Slide smears were prepared using 10 μl of fresh plain blood following the protocol of previous work (Lulijwa et al ., 2020). Slides were air‐dried overnight, fixed with methanol and stained with Giemsa (51,811,826, Sigma‐Aldrich, Auckland, New Zealand).…”

“…Fish liver, muscle and serum metabolites were extracted and derivatized according to detailed standard protocols reported elsewhere (Lulijwa et al ., 2020; Villas‐Boas et al ., 2011; Young et al ., 2019). Briefly, metabolites were co‐extracted with 20 μl L‐alanine‐2,3,3,3‐d4 (d 4 alanine 10 mM) as an internal standard in a cold methanol:water (MeOH:H 2 O) solution in series of 50% and 80% methanol.…”

“…Fish liver, muscle and serum metabolites were extracted and derivatized according to detailed standard protocols reported elsewhere (Lulijwa et al, 2020;Villas-Boas et al, 2011;Young et al, 2019).…”

Molecular cloning, identification and expression analysis of MDA5/MAVS/TRAF3/TANK/TBK1, five pivotal molecules of RLR signalling pathway in turbot ( Scophthalmus maximus )

“…The TANK expression pattern result in turbot revealed high expression level in liver followed by kidney; however, no similar work has been yet carried out which need further information to compare the tissue-specific expression of TANK in teleosts. The expression pattern of TBK1 gene in turbot was similar to that in Dicentrarchus labrax in gonad and brain (Valero et al, 2015), followed by Larimichthys crocea in brain, gills, heart and intestine (Zhang et al, 2015) with little In several previous and recent studies, it is evidently reported that there is an involvement of the fish PRRs genes under viral infection and induction conditions such as poly (I:C) and TRBIV (Andresen et al, 2020;Go et al, 2016;Li et al, 2020;Lü et al, 2005;Lulijwa et al, 2020;Su et al, 2011;Xiao et al, 2011). immunology (Fortier et al, 2004).…”