Reevaluation of Amino Acid Requirements for Laying Hens: Lysine Requirements

Good work ..The expression lysine as digestible values is a good manner to study the requirements..

It is a usefull article for laying hens farmers and feed formulator.First we will be overview the research of different authors for daily lysine requirement. The result obtained were dependant on the productivity of the birds. Genetic progress has a considerable influence on the dietry amino acid concentration. The best flock now a days have a daily egg outputs of over 58 gm of egg mass up to 60 weeks of age and the best bird in a flock produce one egg every day untill 80 weeks. So we can not define a requirement with only one experiment or two. Joly also used white and brown birds from 34- 50 weeks of age, the protein level was low (15.2 [percent]), diet were supplemented in Methionine, Isoleucine, Tryptpphan, Threonine and found daily digestible Lysine requirement 893 mg for white birds, 804 mg for brown birds.The productivity was found 57 gm of egg mass per day over the period.Goulards found digestible lysine 0.710[percent] for white and 0.691[percent] for brown layer, dietry egg mass 46-51 gm and daily requirement of 705 to 722 mg.we will be reached the result from the above discussion that that 1- There is a strong correlation between the requirement and the productivity. 2- A lysine defficiency affects all production parameters, egg weight, egg number and feed efficiency except for feed consumption. 3- The requirement of arround 13.34 -15 mg of digestible lysine to produce 1 mg of egg mass. To avoid the risk of defficiency during early weeks (18-28), advice to increase the ammino acid level by 6[percent].