Protein Level and Efficiency of Feed Mixture for Common Carp (Cyprinus Carpio)

The quality of fish feed and its nutritional value are important for fish production. From an economic point of view it is vital to ensure a cheaper final product while from the nutritional aspects it is essential to fulfill the requirements of fish. The aim of this study was to investigate the digestibility and effect of feed mixtures with different protein content on growth of carp fry. The experiment was carried out at the Laboratory for fish nutrition of the Faculty of Agriculture, University of Belgrade, for 90 days. Fish were fed with concentrate mixtures having 38% (A), 41% (B) and 44% (C) of proteins. The bigger share of the protein part in A were plant proteins (PP), in C fish meal (FM), while in B the share of FM and PP was approximately the same. Results showed significant differences between digestibility of different feed mixture. The digestibility of protein and fat were higher in fish fed diets with higher protein content. Digestibility of nitrogen-free extracts (NFE), energy and digestible energy was not statistically significant (p> 0.05) regardless of the level of protein in the diet. The results indicate that the increase in the digestibility of proteins is in accordance with the increase in protein content in the diet e.g. diets with higher content of FM