Effects of different levels of plant proteins on the ongrowing of meagre (Argyrosomus regius) juveniles at low temperatures

Abstract

Four experimental diets with different inclusion levels of plant proteins and fish protein hydrolysates were compared with a commercial diet for meagre (Argyrosomus regius) ongrowing at optimal and suboptimal water temperature. Results in terms of growth in length and weight, conversion efficiency, dietary feed intake and utilization, body composition (whole fish and liver) as well as enzyme and immunological activities are presented. Fish growth was significantly reduced by the inclusion of plant proteins, although further addition of fish protein hydrolysates improved the results. Daily feed intake was not affected by plant protein inclusion in the diets, although the group fed the highest inclusion level showed lower ingestion than the rest of the groups, probably as a consequence of a reduced dietary palatability. The decrease in water temperature during the second part of the experiment had a negative effect on feed intake and fish growth. Gross visceral morphology of meagre fed the experimental diets was not affected, but muscle weight was significantly reduced. Whole body and liver composition was not affected with plant protein inclusion. However, the inclusion of fish protein hydrolysates resulted in a significant increase in fat content, especially in liver cholesterol and steryl esters, with a parallel reduction in protein. Brush border enzymes were affected by plant protein inclusion as well as serum lysozyme that significantly increased in the fish fed the highest inclusion level. As a conclusion, up to 315 g kg−1 plant protein (76.2% of total protein content) can be included in the diet for meagre without affecting growth or feed utilization. Higher inclusion levels can also be used if at least 5% fish protein hydrolysate is also included.

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

“…Seasonal changes in those abiotic factors affect and modulate the physiological responses, which force fish to vary osmoregulatory, metabolic and growth rates for efficient environmental adaptation (Boeuf andPayan 2001, Vargas-Chacoff et al 2009a). Low water temperatures could induce fasting in cultured species, modifying their metabolic status and triggering an allostatic overload (Polakof et al 2006, Estévez et al 2011, as occurs in the gilthead seabream (Sparus aurata) (Ibarz et al 2010). On the other hand, short but intensive rainfall in autumn/winter (usual in southwestern Spain) can decrease water salinity in earthen ponds, inducing osmotic and consequently metabolic challenges in cultured fish (Vargas-Chacoff et al 2009a).…”

“…Other aspects such as larval culture have been clarified by a series of studies focusing on larval growth in captivity (Cárdenas et al 2008, Vallés and Estevez 2013, Suzer et al 2013, Papadakis et al 2013) and studies of food composition have optimized the diet for this species (Piccolo et al 2008, Chatzifotis et al 2010, Estévez et al 2011, Sáenz de Rodrigáñez et al 2013. Finally, studies of the growth of A. regius in tanks (Pastor et al 2002, Cárdenas 2010, Estévez et al 2011, Chatzifotis et al 2012) and cages (Pastor et al 2002, García-Mesa et al 2009) have shown high growth rates in both systems. However, only a few studies have tested the maintenance of this species in earthen ponds (Jiménez et al 2005), a culture system used mainly for aquaculture activity in Mediterranean countries such as Spain, Portugal (Dinis et al 1999) and even Egypt (El-Shebly et al 2007).…”

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.…”

Reproductive strategy and fecundity of meagre <i>Argyrosomus regius</i> Asso, 1801 (Pisces: Sciaenidae): implications for restocking programs

“…Some factors affecting cost-effectiveness are well known. For example, the somatic growth, feeding and larval survival of meagre have been described (Piccolo et al 2008, Chatzifotis et al 2010, Estévez et al 2010, Roo et al 2010) because of its commercial interest and it has been shown to be a feasible candidate for the diversification of finfish marine aquaculture (Quéméner 2002, Jiménez et al 2005.…”