Growth performance of common carp (Cyprinus carpio L.) fingerlings fed with various protein levels

Common carp (Cyprinus carpio L.) is one of the most used freshwater species in aquaculture worldwide. The species and its subspecies have very good skills for farm production system breeding. Although nutritional aspects of energy and protein needs were fairly well studied and enshrined, new trends proposes a "live food" nutrition and sustainable breeding of the species, with the best capitalization of the local resources. Food and Agricultural Organization of the United Nations (FAO) proposed two decades ago a manual on the production of live food for aquaculture, but few applications were recorded, mainly because of competition with intensive and semi-intensive breeding systems. Romania is natural range of C. carpio distribution and has a long tradition in carp breeding. Moreover, traditional fish farms which practice an extensive breeding could easily use natural resources of live food. Three types of fodder have been used to feed indigenous carp fingerlings, from which one is 100% natural live food - Musca domestica and Eisenia fetida, a mixture one of those two species (50%) with maize (Zea mays) 50%, respectively a classic granulated fodder with fish meal. Crude protein level ranged from 30 to 54.77%. Best food conversion rate and average daily gains were obtained by using 100% live food, followed by mixture of live food with maize and at the last place was recorded the classical fodder. Biochemical and hematological sanguine parameters were in normal physiological limits for this age category and for all three types of fodder.