[Rapeseed and rapeseed meal as components in diets of laying hens]

In an experiment with 405 Hisex white hens rations with 5-20% low glucosinolate rapeseed (RS) or rapeseed meal (RSM) of 00 quality were used. Feed intake, egg production, individual egg weight and live weight gain were reduced in hens fed 5-20% RS and 10-20% RSM. There was a positive correlation between the RS proportion in the ration and the thyroid weight as well as the iodine content of the thyroid. The relation between the iodine content related to one gram of thyroid and the RS proportion was not significant. There were not any significant differences between the RSM groups and the iodine content of the thyroid. The T3 and T4 concentrations in the blood plasma was independent of the RS- or RSM-proportion in the diet. The outward egg quality was not influenced by feeding. The Haugh units were lower when RS or RSM were offered. The fatty acid pattern of the yolk was changed by RS or RSM feeding, particularly the proportion of oleic acid increased. We concluded from the results, RS cannot be recommended for feeding white hens and only a maximum of 5% RSM should be administered.