FRESHWATER FISH OF NORTHERN ITALY: FROM THE VALORIZATION OF WILD UNEXPLOITED SPECIES TO NEW FARMING PERSPECTIVES

Northern Italy freshwater fish production derive from inland fisheries and mainly from aquaculture. Both of them registered some problems. The number of freshwater fishermen is in a steady reduction, caused by the modification of lakes population, that is switching from the presence of high valued fish to others cheaper species which have a limited market. Freshwater farmers suffer the competition of marine and imported products. It is necessary to find a way to valorize Northern Italian freshwater fish production. In this thesis we analyzed the chemical composition and fatty acid profile of 15 species caught in North Italy lakes, sampling species with a high value and species which are not appreciated by Italian consumers. All of them showed an high nutritional value. Species like rudd, roach or crucian carp, that now have a limited market could represent a good source of protein and lipid of great quality. Fish processing could be a way to increase the value of cheaper fish; across the lake there is the tradition of salting and drying landlocked shad, transforming them in missoltini. We analyzed this product, showing its nutritional characteristics and focusing on the formation of histamine that could occur if the processing is not performed properly. We analyzed missoltino made by seven traditional producers, finding an high histamine content in products made by three of them. We identify 99 bacterial strains, of which the majority (71) showed the ability of produce histamine and 7 were high histamine former bacteria. Despite these results we were not able to identify which bacteria strains was responsible of the histamine presence in our samples. The only parameter that we found linked to the histamine presence was the water content of products. Histamine was formed in missoltini where the drying phase of production had not be able to remove the maximum amount of water from the product. The farming of new fish species, which presence in market is now limited, could be a way to have a higher income to fish farmers. Tench is considered one potential species for the differentiation of freshwater fish productions. We tested the response of this species in intensive aquaculture. Our results were acceptable but not satisfying, probably due to the genetic strain of tench used, which did not fit to intensive farming conditions. The use of spirulina in tench feeding showed promising results, that should be confirmed in further studies.