Eighty pigs of (Polish Landrace x Large White) x Hampshire crossbreed (40 gilts and 40 barrows) were allotted to four treatments and fed with basal diets for the growing (30–70 kg body weight, BW) and finishing periods (70–110 kg BW). The growing-finishing pigs in group I were fed diets supplemented with flavophospholipol at a dose of 10 mg kg^-1; group II, with the addition of animal plasma protein (30 g kg^-1 of mixture); group III, with added immunized egg protein (2 g k g^-1 of mixture); group IV, with the addition of mannanooligosaccharide (5 g kg^-1 of diet). The pigs were housed in pens (two gilts or two barrows per pen). Feed and water were available ad libitum. The animals were weighed at the start of the experiment, in the middle of it, and at slaughter. Average daily gains and feed utilization were significantly affected by animal plasma protein supplementation. Backfat thickness over the shoulder as well as leaf fat weights were reduced significantly in pigs fed the diets supplemented with mannanooligosaccharide. The lean of ham and loin eye area increased significantly in the group with egg protein added to the diet.