Abstract
Common carp (Cyprinus carpio L.) aquaculture remains the foundation of global fish farming, whereas grain of wheat, barley and maize have traditionally served as the principal low-cost energy source in feeds. However, the extensive use of cereal feedstuffs is constrained by their limited biological value and insufficient digestibility of individual constituents. The aim of the study is to generalize and analyze information on methods for enhancing the nutritional value of grain used as feed for carp. The methodological framework comprised the search, selection, systematization and comparative analysis of scientific publications from domestic and international bibliographic databases covering the period of 2010–2025. It has been established that traditional grain raw materials are characterized by an insufficient content of digestible protein, averaging 8–12 %, a deficiency of essential amino acids, primarily lysine and methionine, as well as a significant proportion of poorly digestible carbohydrates. The digestibility of starchy polysaccharides in grain by carp does not exceed 20–25 %. The review examines approaches to improving the feed value of grain, including the use of non-traditional cereal crops, early-maturity grain and grain pile, grain processing by-products, germination, and mechanical and thermal processing. The utilization of non-traditional crops and grain processing by-products contributes to increased protein content in the diet and reduced feed costs. The use of germinated grain is accompanied by an improved amino acid profile and enhanced vitamin value. Rolling, grinding and thermal processing, including extrusion, increase nutrient availability and feed utilization efficiency.
The conclusion is drawn regarding the advisability of a differentiated selection of grain processing methods, taking into account the resource availability of farms, production conditions and economic efficiency.