Different Dietary Levels of Rapeseed Meal Effects on Egg Quality Characteristics in Indigenous Breeding Hens

This experiment was conducted to investigate the effect of feeding 5 experimental diets containing 0, 5, 10, 15 and 20% rapeseed meal on egg quality characteristics of Iranian indigenous breeding hens at different ages. The experimental period started at 25 weeks followed by 4 periods of 28-day cycle to 41 weeks of age. The egg and eggshell quality indices (egg weight, yolk weight, yolk index, Haugh unit, eggshell weight, eggshell thickness, and eggshell strength) were determined 4 times at 28, 32, 36 and 40 weeks of age. The proportion rate of rapeseed meal in the diet did not affect egg weight, yolk weight, yolk weight ratio and yolk color index. Increasing the dietary level of rapeseed meal led to a significant improvement of Haugh units (p<0.05). The highest and lowest eggshell weight, eggshell weight ratio, eggshell thickness and eggshell strength were recorded in control and 5% rapeseed meal groups, respectively (p<0.05). Egg weight, yolk weight, yolk weight ratio, eggshell weight increased and eggshell thickness decreased as the hens age increased (p<0.05). Interaction of the rapeseed meal and age was not significant for any of traits. The results showed that 15 to 20% soybean meal substitution with rapeseed meal can improve Haugh units without inducing any adverse effects on egg weight, yolk weight and yolk color index in Iranian indigenous breeding hens.

Keywords:

Rapeseed meal , Indigenous breeding hen , Egg quality , Hen age