Abstract
The effects of excess dietary choline, rapeseed meal and fish meal on the fishy tainted eggs of White Leghorn hens were studied. Single Comb White Leghorn hens at 96 weeks of age with high egg production rate were divided into four dietary groups of 10 hens each, and consumed a control diet for 10 days. After then, the control diet was successively switched to 0.46, 0.68 and 0.90% choline diets in the second group, to 5.0, 10.0 and 15.0% rapeseed meal diets in the third groups, and to 4.0, 80 and 12.0% fish meal diets in the fourth group at 10 days internals. The first group was fed the control diet throughout the experimental period. The eggs laid on the odd days were used for determination of trimethylamine (TMA), and those laid on the odd days on the experimental diets were used for sensory test. Body weight, feed intake and egg production rate tended to decrease with increasing dietary choline, rapeseed meal and fish meal levels. TMA in egg albumen was less than 5% of total TMA in egg. TMA in egg yolk ranged from 0.46 to 1.01μg/g yolk in all experimental diets and period, which were less than the threshold value, 1.05μg/g. No fishy tainted eggs in all dietary groups were detected by the sensory test.
