Nutritional quality of the fresh and processed grey mullet (Mugilidae) products: a short review including data concerning fish from freshwater

This short review compiles the data concerning the quality of flesh, processed roe and smoked fillets of grey mullets (Mugilidae), including when available the data concerning the fish from freshwater and in particular those from Tunisian reservoirs. The biochemical and mineral composition of the fish, the nutritional benefits and the potential health risks related to the consumption of fish products are discussed with regard to human health, taking into consideration the nutritional recommendations and normative toxicological limits defined by leading health authorities. Flesh proximal compositions of fish from freshwater are relatively scarce, but the few available lipid data are within the very large proximal range (from less than 1% to more than 11%) reported for grey mullets in general. Most of the studies reveal the predominance of unsaturated fatty acids with a substantial proportion ω3 type not only for fish from marine environment but also for those from freshwater. Flesh constitutes a source of essential amino acids and mineral nutrients too. The mullets are generally reported to be safe for human consumption except the fish from heavily contaminated zones. Globally, it should be regarded as an interesting contribution to a healthy diet. The mullets are also greatly appreciated for the production of salted and dried roe as well as smoked fillets, which allow increasing their economic value while preserving products health beneficial attributes. Data concerning processing mullet's roe from freshwater are missing, but it may be supposed that these roes have acceptable texture, taste and flavour as they are highly sought by connoisseurs. It is recommended to perform studies on the qualities of freshwater mullet's roe and to look for labelling the origin for both the roes and the smoked fillets of mullet from Tunisian reservoirs dedicated to the production of drinking water as it would guarantee that the fish come from unpolluted environments

Nutritional quality of the fresh and processed grey mullet (Mugilidae) products: a short review including data concerning fish from freshwater

This short review compiles the data concerning the quality of flesh, processed roe and smoked fillets of grey mullets (Mugilidae), including when available the data concerning the fish from freshwater and in particular those from Tunisian reservoirs. The biochemical and mineral composition of the fish, the nutritional benefits and the potential health risks related to the consumption of fish products are discussed with regard to human health, taking into consideration the nutritional recommendations and normative toxicological limits defined by leading health authorities. Flesh proximal compositions of fish from freshwater are relatively scarce, but the few available lipid data are within the very large proximal range (from less than 1% to more than 11%) reported for grey mullets in general. Most of the studies reveal the predominance of unsaturated fatty acids with a substantial proportion ω3 type not only for fish from marine environment but also for those from freshwater. Flesh constitutes a source of essential amino acids and mineral nutrients too. The mullets are generally reported to be safe for human consumption except the fish from heavily contaminated zones. Globally, it should be regarded as an interesting contribution to a healthy diet. The mullets are also greatly appreciated for the production of salted and dried roe as well as smoked fillets, which allow increasing their economic value while preserving products health beneficial attributes. Data concerning processing mullet's roe from freshwater are missing, but it may be supposed that these roes have acceptable texture, taste and flavour as they are highly sought by connoisseurs. It is recommended to perform studies on the qualities of freshwater mullet's roe and to look for labelling the origin for both the roes and the smoked fillets of mullet from Tunisian reservoirs dedicated to the production of drinking water as it would guarantee that the fish come from unpolluted environments

Antimicrobial and antioxidant activities of cactus polyphenols extract on seafood preservation

The present work investigated the antimicrobial and antioxidant activities of polyphenols extracted from cactus (Opuntia ficus indica) fruit-peels on sardine fillets during refrigerated storage. Biochemical, microbiological and sensorial indicators of treated sardine fillets; were studied comparatively to control lot. Microbial communities were characterized using phenotyping and molecular identification of bacterial isolates; and culture-independent method (PCR-TTGE) for fingerprinting of bacterial DNA extracted from fillets. A principal component analysis (PCA) of all the studied descriptors and variables revealed that discrimination along first principal component (PC1) was mainly correlated positively with peroxidation level and storage time but negatively with polyphenol treatment while along second component (PC2) it was mainly positively correlated to polyphenols treatment and polyene index; confirming the effect of treatment on preservation of sardine fillets. Sensory data studied by the correspondence factorial analysis (CFA) revealed that the addition polyphenols extract extended the shelf life of sardines without altering their sensorial properties. Cactus fruit-peels appeared a promising source of natural bio-preservative agent for aquatic food processing

Comparison of growth, digestive system maturation and skeletal development in sea bass larvae reared in an intensive or a mesocosm system

The quality of development in intensive or mesocosm hatchery-reared Dicentrarchus labrax larvae was investigated using physiological indicators assessing ontogeny. Larvae were reared in intensive (120 L tanks) and in mesocosm systems (20 m(3) enclosures) with the same feeding sequence, excluding the wild zooplankton naturally available in mesocosms. Faster growth was recorded since early development [16 day after hatching (DAH)] in the mesocosm. Maturation of the digestive system also occurred earlier as indicated by the higher amylase secretion ratios, the intestinal maturation index (alkaline phosphatase/leucine-alanine peptidase and aminopeptidase-N/leucine-alanine peptidase ratios) and the more developed intestinal epithelium at 23 DAH. Nevertheless, the delay in digestive maturation in the intensive system seemed retrieved within few days. In both the groups, the number of vertebrae ranged between 24 and 26, with the dominant class being 25 vertebrae. However, the distributions differed between treatments for meristic characteristics, ossification stages and incidence of malformation types. Loss of a vertebra was more frequent in the intensive system, while the appearance of an additional vertebra was more frequent in the mesocosm. Ossification at 37 DAH was also more advanced in the mesocosm in addition to a lesser rate and severity of skeletal malformations. It is suggested that the early nutritional contribution of mesocosm wild zooplankton, yet at densities of 0.2-0.7 prey mL(-1), had key effects on larvae development since the early stages

Differences in nutrient content of eggs and larvae as indicators for improvement of broodstock nutrition in walleye (Sander vitreus) production

L’étude avait pour but d’accroître les connaissances sur les besoins nutritifs des dorés jaunes (Sander vitreus (Mitchill, 1818)) géniteurs. Deux traitements alimentaires ont été mis à l’essai, le premier consistant en des morceaux de maquereau (Scomber scombrus L., 1758) gelés avec un supplément de boulettes sèches expérimentales et le deuxième, de morceaux de maquereau gelés avec un supplément de boulettes de truite commerciales. Les œufs de géniteurs sauvages présentaient le succès d’éclosion le plus élevé. Les œufs et larves des poissons sauvages présentaient les plus hautes teneurs en acides gras linoléique (ALO; 18:2 n–6) et linolénique (ALN; 18:3 n–3) dans les lipides neutres. Ils présentaient aussi les plus faibles teneurs d’acide docosahexaénoïque (ADH) dans les lipides tant neutres que polaires. Les résultats semblent souligner l’importance de différents acides aminés, notamment la leucine, la lysine, la méthionine et la serine, pour une meilleure survie des œufs. Les teneurs en vitamine A1 étaient semblables dans les œufs de poissons sauvages et les géniteurs plus jeunes pour les deux groupes de traitement, mais dix fois plus faibles dans les œufs de géniteurs plus âgés. Les œufs de poissons sauvages présentaient les teneurs en vitamine A2 les plus élevées. Nos résultats montrent qu’aucun des deux régimes alimentaires n’a produit une qualité d’œufs ou de larves comparable à celle des poissons sauvages. -- Mots-clés : doré ; Sander vitreus ; percidés ; besoins nutritifs ; acides gras ; acides aminés ; vitamine A ; développement des embryons ; vitellus

Allometric growth patterns and development in larvae and juveniles of thick-lipped grey mullet Chelon labrosus reared in mesocosm conditions

Allometric growth and ontogeny were studied in thick-lipped grey mullet Chelon labrosus reared in mesocosms from 1 to 71 day post hatching (dph). Multivariate allometric analysis of morphometric growth distinguished three distinct developmental stanzas separated by two morphometric metamorphosis lengths (L-m1=4.46 +/- 0.06mm; L-m2= 28.56 +/- 1.04mm). Body mass growth also showed three distinct episodes separated by two inflections, correlated with morpho-functional changes. First episode concerned pre-flexion larvae and ended around 4.5mm-L-T (14-dph), coinciding with estimated L-m1. It was distinguished by reduced growth, but intense morphogenesis and differentiation processes. Organogenesis and allometric changes indicated that development priorities concerned feeding efficiency, by improving detection ability (sensory system development), ingestion capacity (head growth) and assimilation performance (digestive system differentiation), together with respiration efficiency (gill development). Second episode concerned post-flexion larvae and, ended around 8.6mm-L-T (25-dph). It was distinguished by fast growth of trunk and tail, acquisition of adult axial muscle distribution and completion of gill filament development, improving locomotion and oxygenation performances. It corresponded to transition towards metamorphosing stage as indicated by later isometric growth, musculature maturation and acquisition of juvenile phenotype. Metamorphosis seemed to end at L-m2, suggesting to avoid zootechnic handling before this size