Impact Of Chromium On Performance Of Laying Hens, Egg Quality And Blood Biochemical Indicators

In a 2 x 6 factorial experiment , five hundred and fifty Roman laying hens , 57-week age , were randomly divided into 11 groups to study the effects of supplemental dietary of different chromium sources (chromium nicolinale and chromium yeast) and chromium level on egg production performance , egg quality , blood biochemical parameters of laying hens , and the deposit of chromium in eggs . Group control was fed a basal diet, the groups 1 to 5 were fed basal diet supp:100-500μg/kg (in the form of chromium nicolinale) ;the groups 6 to 10 were fed basal diet supp: 100-500μg/kg (in the form of chromium yeast).The result showed that the laying hens fed the diet containing 200μg/kg chromium nicolinale had higher production performance ( P < 0.05 Xhan those fed the control diet. It enhanced egg weight, egg productive ratio significantly and decreased the ratio of feed/egg . There were no significant differences between chromium nicolinale and chromium yeast on the same level ( P>0.05 ) .Dietary chromium supplementation of different level had no significant effect on eggshell strength , eggshell thickness and eggshape index (P>0.05),but enhanced egg white quality .There were no significant differences between the laying hens fed Cr-nicolinale and the Cr-yeast , Dietary chromium supplementation decreased significantly serum glucose , serum total fat , serum urea nitrogen and serum total cholesterol ( P < 0.05 ) , and increased significantly serum total protein level ( P < 0.05 ). The two Cr sources had similar effects on most indices . The Cr accumulated in eggs . at the first 30 days of the whole experiment, the deposit of Cr was increased in eggs when the laying hens were given higher level Cr . Each experimental group had significant markedly differences compared with the control group ( P < 0.01 ) . The experimental groups had significant differences compared with each other ( P < 0.05 ).The deposit of Cr in latter period of experiment was decreased compared with the first 30 days . Each experimental group had significant difference compared with the control group (P < 0.01 ) , But the deposit of Cr in the experimental groups was similar . The deposit of chromium yeast was higher than that of chromium nicolinale . In former period of experiment , the deposit of Cr in yolk was increased and the deposit of Cr-yeast was higher significantly than the deposit of Cr-nicolinale. (P < 0.01 ) In latter period of experiment, the deposit of Cr in yolk was decreased . At the first 30 days, the deposit of Cr in egg white was increased with the high level of Cr. In latter period of experiment , the deposit of Cr in egg white was lower compared with the deposit in former period of experiment , but the deposit of Cr in each experimental group was higher than that of control group . The deposit of chromium had no significant differences between chromium nicolinale and chromium yeast. The deposit of Cr in egg white was higher than that of Cr in yolk . High level chromium decreased yolk cholesterol content in yolk .