EN
Marine algae contain polyunsaturated fatty acids (PUFA), including docosahexaenoic acid (DHA). It was observed that microalgae inhibited the development of protozoa and/or bacteria in the rumen, lowered the total VFA content and the ratio of non-glucogenic volatile acids to glucogenic ones. In research conducted in vitro, microalgae of Schizochytrium sp. inhibited the biohydrogenation of linolenic and linoleic acids, leading to an increase in trans-C 18:1 isomers and DHA. The introduction of microalgae into cows’ diet led to a significant increase in the content of cis-9, trans-11 CLA isomers, EPA and DHA in milk fat. The concentration of CLA in milk fat increased more rapidly than that of DHA. The coefficient of DHA transfer to milk ranged from 5.5% (unprotected algae) to 8.4% (protected ones). Microalgae may be used as an alternative to fish oil in dairy cows’ diets, modifying biohydrogenation processes in the rumen, increasing the content of cis-9, trans-11 CLA in milk, and decreasing the ratio of n-6 to n-3 acids in milk fat.