Effect of untreated and hydrothermally treated rapeseed in feeding of laying hens

Untreated and hydrothermally treated rapeseed were included in laying hen d iets at rates of 0 % (control group), 7.5 %, 15 %, 22.5 % and 30 %, respect ively. The experimental diets were fed to laying hens (Lohmann Brown) from age 27 weeks to age 62 weeks. Performance data and the trimethylamine conte nt of the egg yolks were recorded. Hydrothermal treatment significantly inc reased live weight. However, egg production performance parameters were not influenced by hydrothermal treatment. Increasing the rapeseed content of t he diets to more than 7.5 % significantly decreased laying intensity and eg g mass produced and significantly increased both feed consumption and the f eed conversion ratio. The trimethylamine (TMA) content of the egg yolks was significantly reduced, by about 40 %, by feeding hydrothermally treated ra peseed. There were higher reductions at the higher levels of rapeseed inclu sion. A reduction down to the level of the control group (0.43 mu g/g egg y olk) was not achieved. However, feeding a diet which contained 7.5 % hydrot hermally treated rapeseed gave a TMA content of 0.64 mu g/g yolk. This leve l did not affect the sensory quality of the eggs. In conclusion, up to 7.5 % hydrothermally treated rapeseed can be used in l aying hen diets without any adverse effect on bird performance or egg quali ty.