This study aims to determine how different doses of phytase in diets including extruded soya and lupine seeds affect fatteners' performance, meat quality, bone mineralization, and fatty acid profile. Sixty pigs were divided into three treatment groups. The control group was offered a diet without phytase, whereas the Phy100 and Phy400 groups were provided with 100 g and 400 g of phytase per ton of their diet, respectively. The animals from both experimental groups were characterized by a significantly (p < 0.05) higher body weight gain and lower feed efficiency in the starter period than the control group. Unfortunately, their meat had lower (p < 0.05) fat content, gluteal muscle thickness, and water-holding capacity. In the meat, a higher phosphorus content (p < 0.05) was found, and in the bones, a higher calcium (for Phy400) content was found when phytase was added to the pigs' diet. The pigs from the Phy100 group tended to have higher mean backfat thickness and C18:2 n-6 content in their fat, but lower C22:5 n-3 content, than the other groups. A higher dosage of phytase is not necessary for the diets of fatteners with extruded full-fat soya and lupin seeds.
Keywords: bone mineralization; fatty acid profile; meat quality; performance; phytase; pigs.