Curcumin has antioxidant activity by inhibiting the activity
of inflammatory enzymes or by increasing the synthesis of
glutathione [22]. As a hepatocyte growth factor [12], curcumin
stimulates hepatocyte growth and development and as a
hepatoprotector agent protects the integrity of the hepatocytes
and modulate the growth and cellular responses [23] and to
recure the acute liver cell damage by CCl4 [15], [16].
Therefore, there was a possibility that old laying hen fed
dietary 4% turmeric powder could maintain egg production
performance (Table II) even though their feed intakes (Table
I) were lower compared with the other groups of treatment,
including control.
Liver and ovary are the primary organs of cholesterol
synthesis in laying hen. However, there is little, if any, direct
transfer of ovarian synthesized cholesterol to develop oocyte
[24], [25]. Thus, the contribution of the ovaries on egg
cholesterol levels is minimal. In contrast, cholesterol is readily
transferred from the blood across the ovarian membranes to
develop ova. Therefore most egg yolk cholesterol, if not all,
originates from blood cholesterol. In this experiment, reducing
egg cholesterol content may apparently be attributable with
decreasing blood cholesterol concentration. The results
indicated that cholesterol content (Table III) of the egg
produced by the control group tended to increase up to 6%
with an advance age, while it was decreased up to 16, 24 and
25 % by those of 1, 2 and 4% turmeric supplementation
groups respectively regardless of age. An experiment on rat
fed dietary curcumin [26] was to reduce serum triglyceride
(TG) by 27%, total cholesterol by 33.8%, and LDL-cholesterol
by 56%, respectively as compared to control group