Silvia Testi

Effect of refrigerated storage on muscle lipid quality of sea bass (Dicentrarchus labrax) fed on diets containing different levels of vitamin E

The effect of refrigeration at 1°C on total lipid, phospholipid and fatty acid content of muscle was examined in 4 groups of sea bass (Dicentrarchus labrax) fed diets rich in fish oil and supplemented with increasing levels of vitamin E as antioxidant (139, 254, 495, and 942 ppm, respectively). After 1, 3, 6, 9 and 12 days refrigeration, muscle from the 4 sea bass groups contained increasing concentrations of vitamin E (on average 9.4, 13.1, 19.8 and 28.8 ppm) related to diet levels. However lipid parameters were unaffected until the end of the trial. The results indicate that the experimental conditions preserve lipid quality in sea bass muscle at least over the time range examined, irrespective of dietary formula.

Metabolomics as a powerful tool for molecular quality assessment of the fish Sparus aurata.

The molecular profiles of perchloric acid solutions extracted from the flesh of Sparus aurata fish specimens, produced according to different aquaculture systems, have been investigated. The 1H-NMR spectra of aqueous extracts are indicative of differences in the metabolite content of fish reared under different conditions that are already distinguishable at their capture, and substantially maintain the same differences in their molecular profiles after sixteen days of storage under ice. The fish metabolic profiles are studied by top-down chemometric analysis. The results of this exploratory investigation show that the fish metabolome accurately reflects the rearing conditions. The level of many metabolites co-vary with the rearing conditions and a few metabolites are quantified including glycogen (stress indicator), histidine, alanine and glycine which all display significant changes dependent on the aquaculture system and on the storage times.

Use of centrifuged and preserved microalgae for feeding juvenile Manila clam (Tapes philippinarum): effects on growth and fatty acid composition

Abstract The objective of the present study was to assess the nutritional value of three diets containing commercial preserved microalgae pastes and the relationship of their biochemical composition to the growth rate and fatty acids profile of juvenile Tapes philippinarum. The feeding period was 6 weeks. At a daily ratio of 1% dry weight live weight of the clams–1, the trispecific diet with 40% of I. galbana, 20% of T. suecica and 40% of C. muelleri supported greater growth of animals than either a mixture of 80% of I. galbana and 20% T. suecica or I. galbana alone (P< 0.05). Even the fatty acid profile was significantly modified depending on the composition of the diets. In particular a decrease of EPA was observed in clams with the lowest growth rate.

Growth response and body composition of sharpsnout sea bream (Diplodus puntazzo) fed a high energy diet with different protein levels

Abstract A study was undertaken to determine the effect of a high energy diet with two different protein levels on growth, feed efficiency and whole body composition of sharpsnout sea bream (Diplodus puntazzo). Two isoenergetic diets (24.1–24.7 MJ Kg-1 dry weight) with two different protein levels (46.7 and 52.5% dry weight) were fed to satiety to duplicate groups of 300 fish (initial body weight 27.7 ± 0.2 g) for 94 days. At the end of the experiment, the fish fed 52.5% protein showed a statistically higher (P < 0.05) daily intake rate (DIR) of feed. Feed conversion rate (FCR) was similar among groups. Whole body composition was similar among treatments while the high energy level of the diets significantly modified lipid and moisture content in comparison with fish at the beginning of the experiment. Protein efficiency ratio (PER) and gross protein efficiency (GPE) of fish fed 46.7% protein diet were statistically higher than those for the other diet. It may be concluded that the diet with a lower protein level has given better protein utilization and a protein sparing effect but tended to result in reduced weight gain and feed intake, when compared with diet containing higher protein levels.

Towards the authentication of European sea bass origin through a combination of biometric measurements and multiple analytical techniques

The authenticity of fish products has become an imperative issue for authorities involved in the protection of consumers against fraudulent practices and market stabilization. The present study aimed to provide a method for authentication of European sea bass ( Dicentrarchus labrax) according to the requirements for seafood labels (Regulation 1379/2013/EU). Data on biometric traits, fatty acid profile, elemental composition, and isotopic abundance of wild and reared (intensively, semi-intensively, and extensively) specimens from 18 southern European sources ( n = 160) were collected, clustered in six sets of parameters, and then subjected to multivariate analysis. Correct allocations of subjects according to their production method, origin, and stocking density were demonstrated with good approximation rates (94, 92, and 92%, respectively) using fatty acid profiles. Less satisfying results were obtained using isotopic abundance, biometric traits, and elemental composition. The multivariate analysis also revealed that extensively reared subjects cannot be analytically discriminated from wild subjects.