DIETS IN SEA BASS AND SEA BREAM REARING — DEVELOPMENT AND PROSPECTIVE

Sea bass feeding, in the early beginning of cage culture activity, was based on modified trout pellets and minced sardines. Soon–after knowledge on sea bass and sea bream nutritional needs has been rapidly improved. Recommended balance between digestible proteins and digestible energy (DP/DE) in sea bass and sea bream diets according to different authors is between 19— 21 MJ/kg and 21–24 MJ/kg. Variations of optimal DP/DE in scientific publications in the past, seems to be reflected on significant variation of DP/DE in commercial diets of different producers. Simple method to estimate optimal amino acid balance in the diet is amino acid analysis of whole body protein. Fat content in feed for sea bass and sea bream is around 20 %. Required enrichment with essential fatty acids (especially HUFA n 3) is usually resolved when at least 7% of fish oil is added in the diet. Essential fatty acid (EFA) relative content in farmed sea bass and sea bream muscle fat was found to be similar to the relative content of EFA in fish oil. Vitamins–mineral premixes are standardized and given in higher concentration only in special feeds which can be enriched with immunostimulatns, and used in specific circumstances to improve immunobalance. To establish new feed production for sea bass and sea bream rearing, beside needed knowledge of nutritive value of raw materials and seasonal variations in fish demand, is important to know growth dynamics of cultured organisms and, is the most important — market situation. Competition and increased problems with quality raw material supply are constantly increasing production cost effective value. Today the margin for income–outcome equilibrium are 20 000 t, with the accent that it will be higher in coming years