Increasing Nutritional Value of Cow’s Milk through Diet Manipulation: Fish Oil versus combined Supplementation of Fish Oil and Linseed

The aim of the study was to maximized concentrations of CLA, TVA and acids from the omega-3 family in cow’s milk through the diet supplementation. The experiment was carried out on Forty Polish Holstein Friesian cows averaging 16.2 kg ? 1.42 of milk. The cows were divided into four groups and following treatments were administrated: 300 g fish oil, 150 g fish oil and 250 g linseed of Opal variety, 150 g fish oil and 250 g linseed of Szafir variety. The lowest level of SFA was recorded in milk of cows fed with FO and FOS – 491.60 g kg-1. In all dietary groups the reduction of following fatty acids C8:0, C12:0, C14:0 and C18:0 after the 21st days of supplementation were observed. The lowest level of C8:0 acid was recorded in cows administered with a mixture of FOO. The milk of cows receiving a mixture of FOS contained the lowest concentration of C14:0 acid (reduction by 15.8%) and C18:0 (reduction by 56.63%). The highest level of UFA was found in the FOS group – 467.68 g kg-1. Additionally, after 21th days of supplementation, favorable changes in the content of selected UFA were noted in the following groups: FO - the highest concentration of CLA, LA, DPA, DHA; FOS - the highest concentration of LNA, EPA and TVA and FOO - the highest concentration of GLA. The fatty additives improved nutritional qualities of milk and helped to reduce the level of AI and TI indices. The most preferred values of AI and TI after the 21st days of supplementation were obtained in the group of cows treated with FOS.