Abstract
Due to their high carbohydrate content, cereals are the main source of energy in human, livestock and fish diets, with wheat and maize being the most commonly used crops. Although these two crops, along with rice, satisfy about 50% of human energy requirements, it is necessary to introduce other crops, which are of minor commercial importance. This necessity has been intensified by the growing needs of aquaculture, particularly with respect to carbohydrate requirements. Cereal grains account for an average of 35-45% of the feed ration for common carp (Cyprinus carpio). Experiments have been conducted on the use of barley, triticale and rye as substitutes for wheat and maize. The grains of these replacement cereals are preliminarily subjected to gelatinisation due to the high content of crude starch. Results indicate the possibility of partial or complete substitution (for maize) in some fish feeds. The usability (feed value) of cereals in fish nutrition is ranked in the order: wheat > triticale > maize > barley > rye.