Alberto Felici

Purification and initial characterization of two pheromones from the marine Antarctic ciliate, Euplotes nobilii

Abstract Among a set of wild‐type strains of Euplotes nobilii, every one derived asexually from one specimen isolated from Terra Nova Bay (Ross Sea, Antarctica), two were found to be representative of different mating types mutually capable of inducing each other to form mating pairs through pheromones constitutively secreted into the extracellular environment. Pheromones of strain AC‐1 were purified to homogeneity and shown to be represented by two distinct proteins, that were denoted En‐1 and En‐2. En‐1, secreted in amounts three‐fold greater than En‐2, was determined to have a molecular weight of 5617 and an asparagine at the N‐ter‐minus of its amino acid sequence, while En‐2 has a molecular weight of 6290 and bears an asparctic acid at its N‐terminus. The fact that En‐1 and En‐2 are coreleased by genetically identical cells of the same strain was taken to imply that they carry a het‐erozygotic combination of allelic pheromone genes and that these genes are regulated by relationships of co‐dominance.

Effects of dietary supplementation with krill meal on pigmentation and quality of flesh of rainbow trout (Oncorhynchus mykiss)

Effects of administration of krill meal and synthetic astaxanthin during the finisher phase of the fattening cycle of rainbow trout on flesh pigmentation and quality traits were studied. The inclusion of krill meal increased the body weight and size and decreased the peri-visceral fat and visceral weight indices. The astaxanthin diet produced the highest accumulation of total carotenoids in the fillet compared to the krill meal diet: the difference was significant after 15 days of feeding (2.50 vs 2.10 mg/kg) till the end of the trial (5.00 vs 4.80 mg/kg). The same pattern was observed for astaxanthin concentration with the highest values in the fillets of fish fed the astaxanthin diet. Fillet lightness (L*) was not affected by trout diets whereas redness (a*) and yellowness (b*) were significantly higher in fish fed the astaxanthin diet until day 30 of the trial. Hue was not affected by feeding, whereas chroma was significantly higher in the fish fed astaxanthin throughout the trial except on day 45 of sampling. Trout fed the krill meal diet had a paler pink-red colour on the SalmoFan scale than those receiving the astaxanthin diet. No significant differences emerged in proximate composition and cholesterol content of trout in the two groups. The fatty acid profile of the fillets reflected the fatty acids of the diets administered to the trout: eicosapentaenoic, docosa-hexaenoic and docosapentaenoic acids and total n-3 polyunsaturated fatty acids were significantly higher in the fish fed the krill meal.

Comparative proteomic analysis of two clam species: Chamelea gallina and Tapes philippinarum

Clams have long been a fisheries and aquaculture sector of great importance in Italy, the main resource of fisheries is the Chamelea gallina of indigenous origin, whereas clams breeding is supported almost entirely by the Tapes philippinarum, a species of Indo-Pacific origin. Bivalve molluscs quality depends mainly on the water quality, and then by a series of factors such as water temperature and salinity, gametogenic cycle, food availability, and environmental conditions, that affect the Condition Index. In this work crude extracts obtained from the edible part of Chamelea gallina and Tapes philippinarum were analyzed by a proteomic approach based on a two-dimensional gel electrophoresis followed by liquid chromatography-tandem mass spectrometry, in order to detect biomarkers useful for identification of the two kinds of clams and to assess their nutritional characteristics. As a result, four differentially expressed spots were found and identified, namely enolase, cyclophilin-A, ribosomal protein L13 and actin-1.

Flesh qualitative traits of tub gurnard (Chelidonichthys lucerna L.), a promising species candidate for aquaculture, captured in the middle Adriatic Sea in different seasons

The quality traits of the fillets from tub gurnard (Chelidonichthys lucerna L.) fished in the mid-Adriatic Sea were investigated. Forty fishes per season were sampled to evaluate the proximate composition, cholesterol content and fatty acid profile of fillets. Seasons significantly affected the quality traits of flesh. The protein content ranged from 19.39% in winter to 19.67% in summer, without significant differences. Lipid content was notably higher in spring (2.28%) and summer (2.32%), compared to autumn (1.72%) and winter (1.31%). Energy content was significantly higher in spring (416.45 kJ/100 g) and summer (417.97 kJ/100 g) compared to autumn (391.35 kJ/100 g) and winter (372.79 kJ/100 g). Saturated fatty acid content was highest in spring (35.88%), whereas monounsaturated acid content was not influenced by season. The n-3 polyunsaturated fatty acid content exceeded 37% of total fatty acid content during summer. The n-6/n-3 ratio remained favourably low across all seasons (from 0.16 to 0.18), with a slight significant increase in autumn (0.31). In conclusion, this study indicates that the flesh of tub gurnard has high nutritional value year-round, with the best results (in terms of n-3 polyunsaturated fatty acids) being obtained in summer.

Natural and synthetic pigments used in the pink-red coloration of salmon flesh: methodology of quali-quantitative assessments and sampling results

Abstract In Europe Atlantic salmon leads the first position in the farmed species contest with more than 763,000t (FES, 2007). In the year 2006, Norway produced alone beyond 603,000t followed by the United Kingdom with 128,000t. In these last years, the demand of organic salmon is gradually increased both in domestic and foreign markets. In these fish the pink-red coloration of flesh is obtained by supplementing the feed with shrimp waste meal. In Italy, Coop Italia since three years has started the commercialization in the context of “prodotti a marchio” of Atlantic salmon farmed following prescriptions reported in terms of specification that prohibits the use of synthetic and GM pigments in the feeds. In collaboration with this supermarket company, the Faculty of Veterinary Medicine of Camerino University carried out the quali-quantitative assessments on the presence of molecules and relative isomers that distinguish the natural carotenoid pigment from the synthetic one. Skinned portion of fillet (10g) were collected from dorsal muscle (retro-cranial, central and caudal region), mixed and homogenized and repeatedly extracted with acetone until they were colourless. The pooled extract were filtered and an aliquot (10ml) was centrifugated (2200xg, 5min). The astaxanthin content in the supernatant was determined by HPLC using a Varian ProStar instrument equipped with UV/vis detector using an external astaxanthin standard at detection wavelength 470nm. Analysis was performed on a Varian Kromasil 100 C 18 250x0.3 mm according to Bjerkeng et al. (1997). Identification and determination of stereoisomers were carried out by means of a Sumichiral a-phenylglicine 250x4.6mm column following Abu-Lafi and Turujman method (1999). The analysis performed on all the organic fish have demonstrated the exclusive content of natural pigment. In this group (b.w.=3.9-4.4kg), C-Card for salmonids ranged between 26±1 in 2004 and 21.5±1.3 in 2005 and 21.5±2.1 in 2006. Astaxanthin and isomers decreased from 5.6±0.3mg/kg in 2004 to 2.9±1.1mg/kg in 2006. The low-cost non organic salmon group (b.w.=4.5-4.6kg) resulted pigmented only with synthetic carotenoids and C-card for salmonids ranged between 27.3 in 2004 and 23.7 in 2005 whereas in 2006 it was observed equal to 27. Also in this batch, astaxanthin and isomers decreased passing from 6.5mg/kg in 2004 to 4.9mg/kg in 2006.

Comparison of zootechnical performances, welfare condition and quality traits of hybrid striped bass (Morone chrysops x Morone saxatilis) reared in different Italian farms

Abstract Growth performances of sunshine bass (initial m.b.w.=200±50 g) were examined in 3 different rearing conditions: concrete square basins (HSB-1); raceways (HSB-2); natural ponds (HSB-3). Fish received the same extruded feed (prot. 48.8%; lip. 17.8%). The trial lasted 16 months in HSB-1 and HSB-2 and only 12 months in HSB-3 due to unfavourable welfare status and low growth performances. At harvest (after 16 months), sunshine bass reached a satisfactory mean weight without significant differences between groups. HSB-2 fish were longer with a smaller circumference, probably due to different hydrodynamics of the raceway. Glucose, cholesterol, triglycerides, protein, lactic dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), creatine kinase (CK), glycogen of plasma or tissue were not affected by rearing conditions as well as the proximate composition and the fatty acid profile of the fillet.