The effect of chopped, extruded and pelleted alfalfa silage on the egg quality of organic laying hens

The study showed a mixed effect of silage and the feed mixtures on the parameters measured. For this reason, the daily intake of lipids was calculated to clarify the results. Eggs from hens fed with silage (B, C and D) contained 2.4 times more n-3 fatty acids (FA) than the control (A). Chopped, extruded and pelleted silage showed the same effect on the quality of eggs, but thermally treated silage (C and D) produced yolks with higher concentrations of SFA. The yolks from D exhibited the highest content of odd-numbered fatty acids (15:0, 17:0, 17:1), corresponding to the highest intake of silage. Groups B and C with high canola oil intake showed the highest 18:1 n-9, 22:5 n-3 and MUFA. Furthermore, in spite of the high fat intake, their cholesterol levels were similar to A (A: 12.4; B: 12.3; C: 12.6 mg/g yolk; p > 0.05) due to the anti-cholesterolemic effect of the alfalfa silage. Hens from group D consumed the lowest amount of fat but the highest amount of silage, which corresponding to the lowest level of cholesterol. The fat consumed in the diet was essential in the absorption of carotenoids from the consumed silage. Thus, yolks from the silage groups showed decreasing values for the intensity of red (B: 7.5; C: 6.9; D: 5.2) and yellow (B: 38.6; C: 36.8; D: 32.9) colour as the intake in terms of the amount of fat/silage decreased (B: 6.8; C: 5.0; D: 2.8 fat/10 g silage).