Fratini, Glenda

Messini, Anna

Parisi, Giuliana

English

Florence Research

                                            [Ital J Anim Sci vol.10:s1, 2011]                                                            [page 111]                                             19th Congress of Animal Science and Production Association                                      Italian Journal of Animal Science 2011; volume 10: supplement 1103TQuality and safety in oysters (Crassostrea gigas) andmussels (Mytilus galloprovincialis) reared in Orbetellolagoon (Central Italy)Anna Messini, Giuliana Parisi, Glenda FratiniDipartimento di Biotecnologie Agrarie, Università di Firenze, ItalyCorresponding author: anna.messini@unifi.itShellfish are perishable products due to their biochemical compo-sition. Under refrigerated storage conditions, the shelf life ofthese products is limited by microbiological and enzymaticspoilage. Aim of the work was the evaluation of the influence ofculture site on quality and safety of oysters and mussels, duringthe post-harvest refrigerated storage. In this study, 145 oysters and90 mussels, sampled in Orbetello Lagoon (Italy), at March and atSeptember respectively, were monitored during the storage at 4°C.The shellfish were analysed at 1, 3, 7 and 10 days from the harvest-ing by counting of aerobic psychrotrophic bacterial, pseudomon-ads, coliform bacteria and Escherichia coli. In order to deepen theknowledge about the role of pseudomonads, the significant num-ber of strains from oysters and mussels were isolated. Total DNAwas extracted from the isolates and 16S rDNA was PCR-amplifiedusing FD1 and RD1 primers. Amplicons were subjected to ARDRAanalysis using the restriction endonuclease CfoI. Representativestrains of ARDRA groups were identified by 16S rDNA sequencing.In oysters, the aerobic psychrotrophic bacterial counts was 4.5 and6.0 log CFUg–1 on the 1st and the 10th day, respectively; thepseudomonads values was 3.2 and 5.3 log CFUg–1 on the 1st and the10th day respectively. In mussels, the aerobic psychrotrophic bacte-rial count was 5.8 and 6.2 log CFUg–1 on the 1st and the 10th day,respectively; the pseudomonads value was 4.2 and 6.2 log CFUg–1on the 1st and the 10th day respectively. The coliform number wasalways below the limit permitted by the Italian law and Escherichiacoli was always undetected. 16S rDNA sequencing indicated thatthe analysed isolates (pseudomonads), from oysters and safetymussels, belong to Pseudomonas spp.. Oysters and mussels main-tained appreciable quality and safety characteristics during tendays of refrigerated storage.104TMolecular cloning and expression analysis of genesinvolved in the compensatory growth of sea bass(Dicentrarchus labrax)Samuela Corà, Genciana Terova, Simona Rimoldi, Elena Preziosa, Micaela Antonini, Marco SarogliaDipartimento di Biotecnologie e Science Molecolari, Universitàdell’Insubria, Varese, ItalyCorresponding author: genciana.terova@uninsubria.itThere are several descriptions of compensatory growth (a phase ofaccelerated growth when food levels are restored after a period ofgrowth depression) in fish, but the mechanisms involved in suchrapid recovery from fasting are still not fully understood. Suchmechanisms have principally been searched for at the level of totalfish growth, but only little information is available at the molecularlevel. Accordingly, the present study has focused on identifyingcandidate genes which are involved in the compensatory growthinduced by fasting and subsequent refeeding in sea bass(Dicentrarchus labrax). In particular, we report on the molecularcloning and sequencing of genes such as Δ6 desaturase, lipin, per-oxisome proliferator-activated receptor (PPARγ) and oligopeptidetransporter (PepT-1) involved in lipid and protein metabolism.  Wehave also analyzed fasting- and refeeding -induced changes in theexpression of the aforementioned genes, in different tissues, byusing real-time RT-PCR quantification. In sea bass liver, 35 dayswithout feed contributed to a significant increase in Δ6 desat-urase transcript levels as compared to ad libitum fed controls,whereas recovery from fasting (21 days of refeeding) was associ-ated with a significant decrease in Δ6 desaturase mRNA levels.The mRNA levels of lipin and PPARγ in sea bass liver followed thesame pattern: a significant increase after fasting, and a significantdecrease at the end of refeeding.  PepT1 was highly expressed inthe proximal intestine, and fish nutritional status significantlyinfluenced its mRNA copy number inducing a down-regulationduring fasting and an up-regulation during the refeeding.  In con-clusion, our findings offer new information about the dietary reg-ulation of Δ6 desaturase, lipin, PPARγ, and PepT1 genes expres-sion supporting their involvement in sea bass compensatorygrowth induced by refeeding.105TEffects of postmortem storage temperature on seabass (Dicentrarchus labrax) muscle protein degrada-tion: analysis by 2D DIGE and mass spectrometry Elena Preziosa, Samuela Corà, Genciana Terova, Maria Filippa Addis, Tonina Roggio, Marco SarogliaDipartimento di Biotecnologie e Scienze Molecolari, Universitàdell'Insubria, Varese, ItalyCorresponding author: elena.preziosa@uninsubria.itGiven the recognized importance of storage conditions for post-mortem deterioration of fish muscle, this study has focused on thestorage temperature, which is considered the factor with thestrongest impact in this process. Differences in the abundance ofmuscle proteins, due to biological post mortem processes, werestudied by 2D DIGE and MS in 6 sea bass (710±157.87 g) kept ateither 1°C or 18°C for 5 days. The results demonstrated that seabass muscle proteins within the molecular weight and pI valuesinvestigated here are proteolysed to a relatively less degree ascompared to post mortem mammalian muscle. The greatest alter-ations in sea bass filet protein composition can be ascribed to the18°C post mortem storage, and distinct changes appear after 5AQUACULTURE

Quality and safety in oysters (Crassostrea gigas)  and mussels (Mytilus galloprovincialis) reared in Orbetello lagoon (Central Italy)

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Quality and safety in oysters (Crassostrea gigas) and mussels (Mytilus galloprovincialis) reared in Orbetello lagoon (Central Italy)

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