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Effects of
dietary humic
substances
on egg production and egg shell quality of hens after peak
laying period
Ozturk Ergin*,
Coskun Isa, Ocak Nuh and Erener Guray
Department of Animal Science, Faculty of Agriculture,
University of Ondokuz Mayis, Samsun, Turkey.
*Corresponding author. E-mail:
eozturk@omu.edu.tr.
Tel: 90-362-3121919 x 1144, Fax: 90-362-4576034.
Accepted 3 January, 2008 |
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Ninety
Isa Brown layers from 51 to 61 weeks
of age were allocated
to three treatment groups, namely H0, H1
and H2. Control (H0) hens were fed a
commercial diet while H1 and H2 hens
were fed a diet including 30 and 90 ppm dietary humic acid
in liquid form, respectively. Hens were placed individually
in cages in three tier batteries. Egg production (% hen-day)
in the H2 group was higher (P < 0.05) than
control group. Egg mass of H2 hens was higher (P
< 0.05) than H0 and H1 hens. Total
feed intake in H2 group was significantly higher
(P < 0.05) than H1 group. Egg shell thickness of
H1 hens was higher (P < 0.05) than H2
hens. Egg shell strength of H1 hens was higher (P
< 0.05) than control and H2 hens. Egg weight,
feed conversation ratio and yolk weight were not affected by
dietary
humic substances.
These results indicated that the supplementation of 30 ppm
humic acid into the diet may increase the egg shell strength
without affecting egg production and feed efficiency
compared to control counterparts.
Key words:
Humic
substances, poultry, feed
additive, egg production,
egg quality. |
