Yearly growth and metabolic changes in earthen pond-cultured meagre <em>Argyrosomus regius</em>

Abstract

Summary:Metabolic modifications associated with natural environmental conditions were assessed in the meagre Argyrosomus regius cultured in earthen ponds under natural photoperiod and temperature. Juvenile specimens (90-100 g initial weight) were sampled (plasma, liver and muscle) every two months for 18 months (between December 2004 and May 2006). Specimens showed seasonal variations in growth rate, with the highest values in spring and summer. Plasmatic, hepatic and muscular metabolite levels and hepatic and muscular metabolic enzymes also showed significant variations throughout the year. Enzymatic activity related to carbohydrate metabolism in the liver (HK, FBPase and G6PDH) showed great modifications in summer, increasing glycogenogenic pathways, while amino acid metabolism (GDH and GOT activity) was enhanced in spring and summer. However lipid-related (G3PDH activity) metabolic enzymes did not show a clear seasonal pattern. In muscle, enzymatic activity related to amino acid, lipid and lactate metabolism (LDH-O activity), but not carbohydrate metabolism, showed seasonal changes in parallel with changes in growth rate. Thus A. regius specimens showed a trend to grow in summer months and mobilize their energy reserves in winter. Differences in the hepatic level were observed between the first and the second year of the study, suggesting the possible existence of metabolic changes related to specimen age or size. Our results indicate that growth and metabolic responses in A. regius are environmentally dependent and that this species is a very good candidate for diversification in aquaculture.Keywords: Argyrosomus regius; energy; growth; metabolic parameters; ponds; seasons. Crecimiento y cambios metabólicos anuales en corvina Argyrosomus regius cultivada en esterosResumen: Modificaciones metabólicas asociadas a condiciones ambientales temporales fueron evaluadas en la corvina Argyrosomus regius, cultivadas en esteros con fotoperiodo y temperatura natural. Ejemplares juveniles (90-100 g de peso inicial) fueron muestreados (plasma, hígado y músculo) cada dos meses durante 18 meses (entre diciembre de 2004 y mayo de 2006). Las muestras mostraron variaciones estacionales en la tasa de crecimiento, con valores más altos durante la primavera y el verano. Niveles de metabolitos plasmáticos, hepáticos y musculares, así como las actividades de enzimas metabólicas hepáticas y musculares también presentaron variaciones significativas a lo largo del año. La actividad enzimática relacionada con el metabolismo de carbohidratos en el hígado (HK, FBPasa y G6PDH) mostró altas modificaciones en el verano, el aumento de las vías glucogenogénicas, mientras el metabolismo de aminoácidos (actividades de GDH y GOT) se incrementó en temporadas de primavera y verano. Sin embargo la actividad de G3PDH (enzima metabólica relacionada con los lípidos) no mostró un claro patrón estacional. En el músculo, la actividad enzimática respecto a los aminoácidos, lípidos y el metabolismo del lactato (LDH-O) presentó cambios estacionales en paral...

Environmental Salinity Affects Growth and Metabolism in Fingerling Meagre (Argyrosomus Regius)

“…This information supports previous studies findings that the salinity for optimum growth can vary with fish age [24]. While some information exists for the culture of A. regius juvenile fish in cages and earthen-ponds with natural seawater conditions [3,[25][26][27], there is less information available for the effects on A. regius production at different salinities during the early lifecycle stages [19].…”

“…Consequently, 39 ppt fingerlings demonstrated decreased HSI values and lower growth performance compared to fingerlings at 12 ppt. Therefore, energy metabolites such as liver glycogen may be mobilized through the plasma to satisfy increased osmoregulatory demands rather than being stored, as also recorded for this species under natural environmental conditions [26].…”

Narrowing the Range of Environmental Salinities Where Juvenile Meagre (Argyrosomus regius) Can Be Cultured Based on an Osmoregulatory Pilot Study

“…There are many studies focused on different aspects of the culture of this species such as dietary requirements [25][26][27], stocking density [28], handling procedures [29], and even fillet quality [30]. However, as this is a euryhaline species which naturally spends the first two years of life in estuarine-brackish waters [31,32], and is cultured in salt-marshes with great fluctuations on the environmental salinity throughout the year [33], it should also be relevant to study how environmental salinity affects the osmoregulatory and energy management processes of this species.…”

Rearing diet may determine fish restocking success: a case study of hatchery-reared juvenile meagre, <em>Argyrosomus regius</em>

“…the proportion of food that is converted into biomass) are good (Duncan et al 2013). Recently, meagre growth has been widely studied in different culture systems (Pastor et al 2002, El-Shebly et al 2007, Chatzifotis et al 2010, Vargas-Chacoff et al 2014) and with different diet compositions (Piccolo et al 2008, Estévez et al 2011, Chatzifotis et al 2012, Velazco-Vargas et al 2014 due to the increasing interest in meagre for diversification of aquaculture.…”

“…As meagre is considered an emerging species in European aquaculture (Monfort 2010), numerous studies related to rearing conditions and growth have been conducted in recent years with a view to improving production (Piccolo et al 2008, Roo et al 2010, Estévez et al 2011, Vargas-Chacoff et al 2014, VelazcoVargas et al 2014. In contrast, the main objective of this study was to determine the optimal rearing protocol for obtaining juveniles suitable for restocking, considering both biological and economic aspects.…”