[Substitution of protein animal feed through lysine-supplemented high-protein wheat during the breeding and laying periods of hens. 5. Influence of graded lysine supplements fed during the laying period on the production characteristics of hens].

A large-scale trial was performed with 1500 laying hens which were kept under conditions of industrial egg production. The trial was carried out to investigate whether supplements of L-lysine would increase the food value of high-protein wheat and in which way a proportional decrease of dietary protein by 50% would affect the egg production of the hens. Additionally, studies were made to investigate whether the egg production of the hens was influenced by changes in the plane of feeding of the young hens during their rearing period. Both the young hens and the laying hens received isonitrogenous and isocaloric rations containing 4 graded levels of lysine. All of the 16 groups of the hens received a different diet. This was achieved by suitable combinations within the feeding regime. The control animals received, at all periods of age, food prepared on the basis of government-controlled standard rations. No significant differences in the level of food consumption were observed between the experimental groups whereas the control birds consumed more food (124 g per bird/day) than the experimental hens (120 g per bird/day; alpha less than 0.05). The levels of production were in all groups associated with the lysine content of the ration. The lysine-deficient birds produced the smallest eggs, layed the smallest number of eggs and consumed the largest quantity of food per 100 g of egg weight. The egg production of the hens in groups 11 and 12 (receiving a fish meal ration during the rearing period and a fish meal or wheat ration + 0.15% L-lysine during the laying period) was 70% of that of the birds in the control groups. The results of the present trial suggest that lysine-supplemented high-protein wheat rations for laying hens could be used but care should be taken that the plane of feeding for the young hens will not be too much restricted.