The aim of the research was to determine effects of different combinations of rapeseed and fish oil - instead of soybean oil - on the performance of laying hens and on the profile of fatty acids in egg yolks, especially on n-3 polyunsaturated fatty acid (PUFA), when such oils are added to the diet of laying hens. The research was carried out on 90 laying hens of the Hy-Line hybrid ranging in age from 32 to 36 weeks old. Hens were divided into three groups (30 laying hens per groups) and fed with a commercial mixture that contained 17% of crude protein and 11.6 MJ ME. The research lasted for 28 days. The control group (C) was given diets with soybean oil supplemented in the amount of 5%, and experimental groups (El and E-2) were fed diets that contained a combination of fish and rapeseed oils in different amounts. Diets given to the E-1 group contained 3.5% of fish oil and 1.5% of rapeseed oil, while the E-2 group was fed diets with 1.5% of fish oil and 3.5% of rapeseed oil. Production characteristics of hens were monitored during the whole experiment. Portion of saturated (SFA) and unsaturated fatty acids (MUFA and PUFA), as well as a-linolenic (alpha LNA, C:18:3n-3) eicosapentaenoic (EPA, C20:5n-3) and docosahexaenoic (DHA, C22:6n-3) acid were shown as a percentage of total fatty acids contained in yolk. There were statistically significant differences (P<0.05) only in the hens' end weights and laying intensity between the C and El group, as well as between the C and E-2 group. The portion of SFA in total fatty acids contained in yolk was not statistically significant (P>0.05) among investigated groups. Higher content of MUFA was noticed in both experimental groups, if compared to the control (E-1 41.37%: E-2 40.72%, C 36.95%, P<0.05). Content of aLNA differed significantly (P<0.001) between E, and the control group, and the content of DHA differed significantly (P<0.001) between E, and the control group, as well as between E-2 and the control group. Total n-3 PUFA was increased in the E-1 group for 2.10, and in the E-2 group for 1.41 times than in the control group. The ratio of n-6/n-3 PUFA was the lowest (P<0.05) in egg yolks of the E-1 group (4.01), followed by that of the E-2 group (6.56), and finally that of the control group (11.08).
