Utilization of total and available amino acids in feedstuffs in Laying Hen diets

Abstract

Two experiments were conducted to determine the utilization of total and available amino acids infeedstuffs in laying hen diets. In trail 1 : A total of 192 Hisex Brown hens, 36 weeks old, were applied in a completelyrandomized design experiment. They were randomly allocated into 8 dietary treatments. Each hen was raised in anindividual cage ad libitum access until they reached 48 weeks old. The dietary treatments were 18% protein on a totalamino acid (TAA) basis (T1, control), 18% protein on an available amino acid (AAA) basis (T2, control), 14.6%protein on a TAA basis with methionine, lysine, threonine and tryptophan supplementation (T3), 15.7% protein on anAAA basis with 4 amino acids supplementation (T4), 14.6% protein on a TAA basis with 10% more 4 amino acidsthan T3 (T5), 15.7% protein on an AAA basis with 10% more 4 amino acids than T4 (T6), 13.0% protein on a TAAbasis (ideal protein) with 4 amino acids supplementation (T7) and 13.5% protein on an AAA basis (ideal protein)with 4 amino acids supplementation (T8). Feed intake of hens fed diets T1, T2, T3, T4, T5, T6 and T8 were notsignificantly different (P>0.05), but all were significantly (P<0.05) higher than the group fed diets T7. Eggproduction, egg weight, egg mass and feed conversion ratio were not significantly affected in hens fed dietsformulated on either T1, T2, T3, T4, T5 and T6 (P>0.05), but all were significantly (P<0.05) better than the groupsfed diets T7 and T8. Egg quality in all treatments was not significantly different (P>0.05). The hens of T3, T4, T5, T6,T7 and T8 had a significantly better (P<0.05) yolk color score in comparison with T1 and T2. The cost per kilogramof eggs of hens fed diet T4 was the lowest. In trail 2 : 64 Hisex Brown hens, 48 weeks old, from trial 1 were randomlyallocated into 8 dietary treatments (from trial 1) with 8 hens in each treatment. Excreta was collected for 3 days.Nitrogen intake of hens fed diets T1 and T2 were significantly (P<0.01) higher than other groups. However, nitrogenretention of hens in all dietary treatments showed no significantly different (P>0.05).