Low stocking density negatively affects growth, metabolism and stress pathways in juvenile specimens of meagre (Argyrosomus regius, Asso 1801)

Abstract

The influence of culture density on growth, stress system and metabolism has been assessed in A. regius juveniles submitted to different initial stocking densities (3, 7, 10 and 13 g L-1) for 40 days. On days 0, 12, 27 and 40 of the experiment, biometric parameters were measured. In addition, plasma, liver and muscle samples were taken for biochemical analysis at the end of experimental time. Our results showed better growth rates and feed utilization in those specimens held at high stocking densities when compared to those under low stocking densities. In addition, higher plasma cortisol, glucose and triglycerides levels found in the lowest stocking density tested suggest an activation of the stress system in fish held at this condition. Moreover, no changes in hepatic metabolites were observed, while values of muscle triglycerides, amino acids and lactate enhanced when stocking density increased. In conclusion, the culture of juvenile A. regius at higher initial densities (at least 13 g L-1) ensures better growth and the optimization of the existing facilities, improving welfare of this species in aquaculture systems.

Optimal Stocking Density with the Provision of Self‐feeders for Striped Knifejaw, Oplegnathus fasciatus (Temminck and Schlegel 1844)

“…In addition, this study clearly reveals that the adjustment of a stocking density to 10 and 15 kg/m 3 under a long photoperiod and the provision of a self‐feeder can further improve the growth performance of this species. The higher growth rate from the higher stocking densities in this study agrees with the results of other studies in which a positive relationship between growth rates and stocking densities has been reported (Pirozzi et al ; Millán‐Cubillo et al ). However, growth reduction has also been demonstrated in several finfish species, including Atlantic cod, Gadus morhua , and turbot, Scophthalmus maximus (Irwin et al ; Lambert and Dutil ).…”

“…The higher density not only increased the DFR but also significantly improved the FE through the optimization of digestive processes, especially in SD 10 , which is connected to the higher growth performance from higher densities. This finding correlates with that of Millán‐Cubillo et al (), who demonstrated a significantly higher FE at a higher stocking density in meagre. The higher growth and FE in a higher stocking density (especially SD 10 ) are also supported by the significant improvement in LRE.…”

“…A specific stocking density can have either positive or negative effects on fish growth, and this interaction appears to be species specific (Merino et al ). A number of studies have been carried out to examine the effect of stocking densities on the growth performance of several important aquaculture species, such as gilthead sea bream, Sparus aurata (Montero et al ); Dover sole, Solea solea (Schram et al ); Atlantic salmon, Salmo salar (Hosfeld et al ); European sea bass, Dicentrarchus labrax (Lupatsch et al ); piabanha, Brycon insignis (Tolussi et al ); red porgy, Pagrus pagrus (Laiz‐Carrión et al ); Senegalese sole, Solea senegalensis (Andrade et al ); thick‐lipped gray mullet, Chelon labrosus (de las Heras et al ); and meagre, Argyrosomus regius (Millán‐Cubillo et al ). The fish in these studies were either given restricted rations or were fed until apparent satiation.…”

Effects of clove oil, essential oil of Lippia alba and 2-phe anaesthesia on juvenile meagre, Argyrosomus regius (Asso, 1801)

“…For lactate, although the literature suggests that both glucose and lactate levels are typically correlated with an increase in cortisol (Wendelaar Bonga, ; Barton, ), this was not observed in the present study. Our results for lactate are in accordance with those reports of other authors, who failed when trying to find a relationship between cortisol and lactate values (Iversen et al., ; Small, ; Toni et al., ,b), including A. regius juveniles (Millán‐Cubillo et al., ). Iversen et al.…”

<b>Fish welfare: the state of science by scientometrical analysis

“…The level at which meat quality features are affected by stress depends directly on the severity, length and speed of the stressor. Stress can occur due to production management, stocking rate, transport and slaughter (Millán-Cubillo, Martos-Sitcha, RuizJarabo, Cárdenas, & Mancera, 2016;Shabani, Erikson, Beli, & Rexhepi, 2016). Problems caused by intensive production, together with consumer demand for better quality products, are changing producer interest for sustainable production, because fish quality also includes ethical aspects during their production (Lambooij et al, 2006).…”