Effect of Propolis on the Fish Muscular Development and Histomorphometrical Characteristics

The aim of our study was to evaluate the effect of propolis on mortality of fish eggs due to mycosis, to study its efficacy on the fish growth rate and to analyze the histochemical and ultrastructural characteristics of muscle fibres. We evaluated the muscular development of fish in two different experimental conditions: traditional feeding and feeding with addition of propolis (groups A and B, respectively). The study was carried out on two species of teleosts bred in Italy, Oncorhynchus mykiss (rainbow trout) and Salmo trutta (brown trout). The use of propolis reduced mortality of fish eggs. The muscles were stained for myosin ATPase and succinic dehydrogenase to evaluate fibre type. The area, maximum and minimum diameter for each fibre type in relation to the body length were measured. The animals fed propolis showed a more rapid muscular growth compared to control fed the standard diet. Fibres were larger in the Salmo trutta than in the Oncorhynchus mykiss in both groups. In fish of A group, myotomal muscle, the presence of giant fibres and index of environmental stress was noticed. This type of study is valuable in order to extend the use of propolis as an antifungal agent and a natural product that can improve fish farming.