The effects of pectinases and phosphatases on the bioavailability of protein and interactions between these enzymes were studied. Analysis were performed using an in vitro method simulating conditions of the bird’s intestinal digestion tract. The results obtained were analysed using a two way ANOVA variance analysis (two factor combinations of enzymatic activities – the preparations: Finase P, Finase AP, Rapidase pomaliq 2F, and Energex L). The investigations evidenced that the addition of pectinases and phosphatases significantly influenced protein levels being determined in the dializate. Moreover, it was proved that the cooperation with the pectinase preparations was more effective for the acid phosphatase than for the phytase. It was also confirmed that the high pectin esterase activity in pectinase preparations was a factor limiting the protein bioavailability.