ADDING LIQUORICE EXTRACT TO LAYING HEN DIETS AND ITS EFFECT ON EGG QUALITY CHARACTERISTICS

Abstract

A total of 72 ISA brown laying hens at the age of 24 weeks were reared in cages for three production months. The cages were placed in a semi-closed room , and all necessary requirements for rearing were supplied . The birds were randomly distributed to four treatments , and each treatment contained 18 laying hens with three replications and each replicate contained 6 hens , which were placed in 3 cages. The birds were fed on a production ration , which was supplied with different levels (Treatments) of liquorice extract (T1 : 0.00% as a control , T2 : 0.02% , T3 : 0.04% , and T4 : 0.06%) .Results revealed that significant (P < 0.05) increases in egg weight ,eggshell weight and egg sherr thickness were observed in T3 and T4 during the first , second and third months of production . The weight of egg albumin and the relative weight of egg album and Haugh units of eggs in were significantly improved in extract treatments. No significant differences in albumin hight of all treatments were observed . No significant differences in the weight of yolk and the relative weight of yolkin all treatments were observed . During the second month of production , treatments showed a significant increase in yolk hight , yolk diameter, yolk index in extract treatments compared with that of the control group (T1)It can concluded that adding 0.06% of liquorice extract to laying hen diets resulted in a significant improvement in most of the egg quality characteristics .