Krum V. Nedelkov
Trakia University, Faculty of Veterinary Medicine, Stara Zagora 6000, Bulgaria
Nedelkov, Krum (2023). A new approach for processing and use of sunflower meal. Bulg. J. Agric. Sci., 29(2), 384–389
Sunflower meal (SFM) is a basic and cheap source of feed protein in Bulgaria. Its use is limited by the high content of hulls, which decrease its energy and protein value, and by low content of the amino acids lysine and threonine. In ruminants, an additional problem is a high degradability of protein. For more than ten years a new technology for separation of SFM in low and high cellulose fractions was developed and applied. The low cellulose fraction contains 46 or 50% crude protein (HPSFM-46 or -50). It is suitable for feeding poultry, growing pigs and lactating sows. To increase utilization of diet is necessary for SFM to be supplemented with fat, synthetic amino acids (lysine, threonine), enzymes (phithase, β-glucanase, xylanase, protease) and eventually to be pelleted. The high cellulose fraction (17% crude protein) contains too much impregnation by lignin and silica hulls, which limit including in rations. After additional removal of parts of hulls and supplementation with molasses, minerals and vitamins, it may become acceptable concentrate feed (app. 25% CP) for low productive ruminants (dry cows, first stage of fattening animals, replacing heifers, lambs, and kids). It is necessary to prove possibilities to use this low protein fraction in rations of rabbits, pregnant sows and during the finishing period of fattening pigs. SFM for high productive ruminants should be toasted to decrease degradability and increase utilization of protein. Studies are needed for better estimation of the feeding characteristics of different new SFM products, for optimizing combinations with other protein sources, and for establishing the best composition of feed mixtures for different species and categories of animal. Trials are needed for estimation of the degree of replacement of soybean meal by new SFM products and its economic impact on animal production.