Effects of different dietary iodine levels on egg iodine content and laying performance
1999
Chatchai Janekarnwanit
Experiment was conducted in order to investigate the effect of dietary iodine supplementation on egg yolk iodine content and laying performance. Three hundred 35-WOA Isabrown pullets were randomly subjected to the diets supplemented with five different levels of iodine (0 1 2 3 and 4 ppm) in the form of potassium iodate. All diets were isonitrogenic (17.70 percent crude protein) and isocaloric (2,755 kcal ME/kg) and were provided to the birds for 5-28 day periods. Feed and water were given ad libitum and the lighting program was 16L:8D. The increase (p0.05) of iodine content in egg yolk was observed along with the increase of iodine levels in the diets. The concentration of iodine in egg yolk were 0.84 1.23 1.87 3.20 and 4.08 micro g/g or 13.73 30.46 30.95 53.95 and 69.56 micro g/egg in the control (0 ppm), 1, 2, 3 and 4 ppm groups, respectively. The supplementation of iodine as potassium iodate improved (p0.05) some laying characteristics such as egg weight, egg shell thickness, egg shell weight, egg size, yolk weight, daily feed intake, feed per dozen egg, feed cost per dozen egg, haugh unit and hen mortality when compared to the control group. Nevertheless, iodine supplementation did not significantly improve (p0.05) the egg production, hen body weight change, egg specific gravity, yolk colour and egg mass comparing to the control.
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