Paolo Melotti

Influence of genotype and feeding on chemical composition of organic chicken meat

Abstract The aim of this study was to evaluate the effects of different genotypes and of feeding on meat chemical composition, including fatty acid profile, of chickens reared under organic conditions. Two meat–type fast-growing (FG) and medium-growing (MG), and one egg-type slow-growing (SG) strains were assigned to 2 different diets differing for the protein source: soybean (SB) and faba bean (FB) in partial substitution of soybean. Genotype markedly affected the meat chemical composition. SG breast and thigh meat showed lower content of lipids (P<0.01) than FG. The highest proportions of polyunsaturated fatty acids (PUFA) n-6 and n-3 and the lowest proportion of monounsaturated (MUFA) (P<0.01), as well as the lowest ratio of PUFA n6/n3 (P<0.01) were found in SG breast and thigh meat. MG showed always intermediate values. As for feeding, FB treatment produced only a slight increment of protein in breast and a decrease of fat and ash in thigh meat. Total PUFA and PUFA n-6 resulted lower in both thigh and breast meat of FB groups compared to SB (P<0.01).

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.

Effects of rearing density on rainbow trout welfare, determined by plasmatic and tissue parameters

Abstract The work aimed to determine the welfare status of rainbow trout (50±15 g), intensively reared to commercial size in two concrete raceways (V1, V2) at different stocking densities, to reach final load of 40 kg/m3 and 20 kg/m3, respectively. Throughout the out-phase, plasma parameters and hepatic glycogen content were determined every three months and compared with those of rainbow trout of the same age and mean weight, reared extensively (VE). At the end of the trial significant differences of the monitored parameters were found between rainbow trout reared in raceways (V1, V2) and those held in the reservoir (VE). Plasma triglycerids, total cholesterol and alkaline phosphatase in fish reared intensively were significantly different from fish reared in extensive conditions. The highest levels of these parameters in V1 and V2 could be justified mostly by the administration of balanced feeding and consequent modifications of energetic metabolism and in small part to the high density of the intensive rearing conditions. Transaminases (AST, ALT) increased in V1 and V2 only at the first sampling. Afterwards, the activity of these two enzymes returned to the normal range at the subsequent assays, suggesting a capacity of the rainbow trout to adapt to the severe conditions of confinement, typical of out-basins. No significant differences among groups were observed for total protein, glucose, CK and LDH. A similar situation was also shown for liver glycogen content.

State of the art of Italian aquaculture

According to aquaculture production statistics published by FEAP (2007), Italy is the fifth largest fish producer in the European Union having a total quantity for 2006 estimated around 60,000 t. This data is exclusively referred to rainbow trout (Oncorhynchus mykiss), seabream (Sparus aurata), seabass (Dicentrarchus labrax) and European eel (Anguilla anguilla) but even if we consider the total aquaculture production elaborated by ISMEA (2006) through year 2005 including sturgeons, carps, striped bass, catfish and ornamental fish, Italy ranks fourth with 69,100 t after Norway (655,364 t), Great Britain (141,793 t) and Greece (83,600 t). Over the last 15 years, Italian finfish production has known a decrease related to all the species mainly reared (trout, eel, carps, catfish) except for the eurhyaline species that have had an important expansion (Table 1). Based on these considerations, in this work we describe the main features of fish aquaculture in Italy focalizing the attention to the single sectors of the farmed species and their trend for the future.

State of the art and future trends of European and Italian aquaculture

This paper describes the main features of fish aquaculture in Europe and Italy focusing attention on single sectors of the farmed species and their trend for the future. Over recent years, European and Italian aquaculture have shown a markedly different trend from that of world aquatic production. Asia, particularly China, has recorded a constant and rapid growth and Latin America a moderate development. Nowadays, European farmers are concerned with adapting their product to market demand and diversifying the fish species reared. After a discussion about the main European production statistics regarding finfish aquaculture production, we consider the most important aspects in the promotion of production and consequent consumption of farmed fish.

Largemouth bass (Micropterus salmoides Lacépède): reproduction management and larval rearing in Italy

Riassunto Persico trota (Micropterus salmoides, Lacépède): gestione della riproduzione e allevamento larvale in Italia. Il black bass sta assumendo un’importanza crescente nel nostro Paese sia per la pesca sportiva che per l’alimentazione. Nel biennio 2001-‘02 prove sulla possibilità di riprodurre e allevare gli stadi giovanili di black bass in Italia sono state intraprese a partire da uno stock selezionato di pesci di taglia adeguata. In aprile, alla deposizione delle uova fecondate dai maschi in stagni precedentemente fertilizzati, ha fatto seguito la cattura delle larve e la fase di allevamento in ambiente controllato. La quantità e la tipologia di alimento naturale ed artificiale nei primi mesi di vita e il ricorso a frequenti calibrature sono alla base del successo di questa tecnica che, nell’arco di circa 70 giorni, ha consentito di ottenere giovanili del peso di 1 g. La successiva fase di allevamento ha avuto luogo in stagno dove, a fine ottobre, si è riscontrata una pezzatura media di 5 g ed una sopravvivenza superiore al 50%.

A proposal of method to evaluate the quality of marine waters: Optimisation of 7 days bioassays using Dicentrarchus labrax (L.) juveniles

European sea bass juveniles were exposed to cadmium chloride (CdCl2·2½H2O) as reference toxicant. The effects have been evaluated on the survival rates of the fish throughout 7 days. The LC50 (mg/L of cadmium ions) were: 6.17 mg/L (95% confidence interval: 5.44–6.99) after 24 h and 3.43 mg/L (95% confidence interval: 2.87–4.07) after 7 days exposure. This method could be used as a standard procedure to be conducted in short-term tests for estimating the chronic toxicity of marine waters. The high availability of this species at every stage of the productive cycle gives the opportunity to employ Dicentrarchus labrax as test organism for defining environmental quality standards.

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.

Genetic variability in Trigla lucerna by microsatellite molecular markers isolation.

Tub gurnard (Trigla lucerna L.) has been investigated as a new potential fish for farming in the last years. In fact, the decrease in prices, occurred after the increase of sea bass and sea bream production, is a source of many problems for several Mediterranean fish farm system. For this reason the possibility of diversifying the production has been considered towards other valuable species. The lack of knowledge about the genetic population structure of this Triglidae has prompted the attention on the evaluation of its genetic variability for a better management of broodstock and tub gurnard discrimination according to the geographic distribution. Microsatellite markers have been elected to characterise, at DNA level, the species. They have never been described neither in tub gurnard fish, nor in species from the same suborder. To isolate SSR from the tube gurnard, the FIASCO (Fast Isolation by AFLP of Sequences COntaining repeats) protocol was chosen and 32 loci were isolated. In order to verify the informativity of the isolated loci, three different population, reared and wild type sampled in the middle Adriatic and in the Trieste gulf, were analyzed. Moreover two multiplex PCR were developed and the genotyping of 45 animals, from different populations, was performed showing a high allele ranges between the considered samples.

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.