Br Poult Sci. 2012;53(2):245-56. doi: 10.1080/00071668.2012.681770.
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- 1Department of Food Science, Faculty of Science and Technology, Aarhus University, Tjele, DK-8830, Denmark. mah@agrsci.dk
Abstract
1.
In organic egg production, forage material as part of the diet for
laying hens is mandatory. The purpose of the present study was to
examine the effect of feeding with forage materials including maize
silage, herbs or kale on egg production and various egg quality
parameters of the shell, yolk colour, egg albumen, sensory properties,
fatty acid and carotenoid composition of the egg yolk. 2. A total of 5
dietary treatments were tested for 5 weeks, consisting of a basal organic feed
plus 120 g/hen.d of the following forage materials: 1) maize silage
(control), 2) maize silage incl. 15 g/kg basil, 3) maize silage incl.
30 g/kg basil, 4) maize silage incl. 15 g/kg thyme, or 5) fresh kale
leaves. Each was supplied to three replicates of 20 hens. A total of 300
hens was used. 3. Feed intake, forage intake and laying rate did not
differ with treatment, but egg weight and egg mass produced increased
significantly with the kale treatment. 4. The egg shell strength
tended to be higher with the kale treatment, and egg yolk colour was
significantly more red with the kale treatment and more yellow with
basil and kale treatments. The albumen DM content and albumen gel
strength were lowest with the thyme treatment. By sensory evaluation,
the kale treatment resulted in eggs with less sulphur aroma, higher yolk
colour score, and more sweet and less watery albumen taste.
Furthermore, the eggs of the kale treatment had significantly higher
lutein and β-carotene content. Also, violaxanthin, an orange
xanthophyll, tended to be higher in kale and eggs from hens receiving
kale. 5. In conclusion, forage material, especially basil and kale,
resulted in increased egg production and eggs of high and differentiable
quality.
