The aim of the study was to evaluate the activity of lysosomal enzymes from families: glycosidases such as β-galactosidase (BGAL), β-glucuronidase (BGRD), β-glucosidase (BGLU), N-acetyl-hexosaminidase (HEX), α-glucosidase (AGLU) and α-mannosidase (MAN) as well as aminopeptidases such as alanine aminopeptidase (AlaAP), leucine aminopeptidase (LeuAP), arginine aminopeptidase (ArgAP) and acid phosphatase (AcP) in serum of dairy goats fed the diet with linseed cake or rapeseed meal supplementation. The study was conducted on 16 dairy goats of the Polish White Improved (PWI) breed and lasted for 6 weeks. The goats were divided into two groups, analogous to each other, according to age of goats. The basic diet consisted of corn silage, wilted grass silage and concentrates (oats, triticale, extracted rapeseed meal), supplemented with mineral and vitamin mixtures. The diet of experimental group was supplemented with linseed cake instead of extracted rapeseed meal. The serum samples were taken twice during the experiment: three weeks after the start of the experiment and at the end of supplementation. The milk, protein and lactose yields in control group tended to decrease while in experimental group they increased in the course of the experiment in spite of the fact that the experiment was conducted after the peak of lactation. The obtained results suggested that BGRD and BGAL activities were up-regulated while the other glycosidase MAN was down-regulated after linseed cake in compare to extracted rapeseed meal supplementation. According to aminopeptidases the linseed cake supplementation caused down-regulation of LeuAP and up-regulation of ArgAP activities. The high, positive correlation was found between two aminopeptidases (ArgAP, AcP) and milk, protein and lactose content, while high and negative correlation between three glycosidases (BGRD, BGAL and MAN) and milk, protein and lactose content. Milk fat yield was highly and negatively correlated only with MAN activity.