Stressors Due to Handling Impair Gut Immunity in Meagre (Argyrosomus regius): The Compensatory Role of Dietary L-Tryptophan

Abstract

In the context of intensive aquaculture, meagre ( Argyrosomus regius ) is one of the most important new aquaculture species in Southern Europe and several studies are focused on the optimization of its culture. Nevertheless, stressors such as handling during transport or culture maintenance may affect the immune system, thereby impairing some immune responses or provoking cellular damage. One strategy that has been used to avert this type of negative stress response is the supplementation of amino acids to improve resistance to stress. In this experiment, meagre (105.0 ± 2.6 g, mean ± standard deviation) juveniles were fed two diets for a period of 7 days, the first a commercial diet supplemented with 1% tryptophan (Trp) and second, the same commercial diet without tryptophan supplementation (control group). The effects of two types of handling stressors (air exposure and confinement/netting) on fish fed both diets was evaluated in terms of gene expression of the selected gut immunity markers, such as (1) innate immune response processes: c3 complement ( c3 ), lysozyme ( lys ), and cyclooxygenase ( cox2 ); (2) humoral immune response processes: interferon type 1 ( ifn1 ), mx protein ( mxp ), interleukin 1b ( il-1b ), tumor necrosis factor 1a ( tnf1a ), and interleukin 10 ( il-10 ); (3) antimicrobial peptides: defensin ( def ), hepcidin ( hep ), piscidin ( pis ), and a marker for mitochondrial respiration: glyceraldehyde 3-phosphate dehydrogenase ( gapdh ). Samples of the anterior intestine were collected at 1 and 6 h post-stress (hps). Results showed that in fish fed 1% Trp, the air exposure resulted in an upregulation of gene expression at 6 hps for c3 , lys , cox2 , ifn1 , mxp , il-10 and gapdh , and il-1b and pis . The confinement/netting test for fish fed 1% Trp resulted in an upregulation of c3 and mxp and a downregulation of cox2 , ifn1 , il-1b , tnf1a , il-10 , def , hep , and gapdh at both post-stress times (1 and 6 hps). According to the present study, dietary supplementation with 1% Trp may be considered ...

Linking coping styles and enzymatic activity of energy metabolism in the wedge sole (Dicologlossa cuneata)

“…For this test the following parameters were measured: latency to escape (LE: time, in seconds, taken by each fish to show an escape attempt; escape attempt was defined as an elevation of the body from the net); total number of escape attempts (NEA), and total time spent on escape attempts (TEA: total time in seconds taken by each fish escaping since the first to the last escape attempts) (Silva et al, 2010;Castanheira et al, 2013b). Afterwards fish were returned to their holding tanks and after 30 min blood samples were taken to measure the plasma cortisol content (CORT) since cortisol peaks in fish usually occur 30−60 min after stress (Arends et al, 1999;Castanheira et al, 2013a;Asencio-Alcudia et al, 2019). Blood was collected by puncture from the caudal peduncle into 1 mL heparinized syringes (25 000 units of ammonium heparin/3 mL saline solution 0.9 % NaCl; Sigma, Aldrich, Madrid, Spain, H6279).…”

Use of tissue chromogranin A as chronic and acute stress marker in fish

“…The meagre (Argyrosomus regius) is a relatively new species in aquaculture research, though its stress responses have been previously studied, being like other teleosts (Fanouraki et al, 2011;Samaras et al, 2016;Fernández-Alacid et al, 2019;Asencio-Alcudia et al, 2019;Monteiro et al, 2021;Salamanca et al, 2021;Herrera et al, 2020Herrera et al, , 2021. However, some authors have stated that the differences between basal and stressed values of stress markers are lower than other fish species, though significant (Fanouraki et al, 2011;Samaras et al, 2016).…”

The effects of tryptophan supplementation on stress and aggression in Nile tilapia

“…skin mucus metabolites and blood markers, see Fernández‐Alacid et al., 2019; Hoseini, Taherim Mirghaed, et al., 2020). In addition, this amino acid contributes to (a) protein synthesis, (b) normal growth rates surrounding physiological mechanisms, such as sleep regulation, (c) endocrine activity, (d) cognitive functions, (e) motor activity and (f) aggressive behaviors involving dominance hierarchy (Asencio‐Alcudia et al., 2019; Herrera et al., 2020; Höglund et al., 2019; Hoseini, Yousefi, et al., 2020; Lepage et al., 2003; Lillesaar, 2011).…”