تاثير نسبت هاي مختلف ايده آل ترئونين به ليزين قابل هضم جيره بر عملكرد مرغ هاي تخمگذار

The influence of dietary digestible threonine to lysine ideal ratios on laying hens performance

A total of 300 Hy-line (W-36) hens at 27 wk of age were assigned to 5 treatments in 8 replicates per treatment and 10 birds per replicate in a randomized complete block design. Dietary treatments consisted ideal ratios of digestible threonine to lysine including 0.66, 0.70, 0.74, 0.78 and 0.82. Diets were formulated based on standardized ileal digestible amino acids using Hy-line W-36 guide recommendation. Egg production was recorded daily; feed consumption and egg weight were recorded weekly. Egg mass and feed conversion (g feed/g egg) were calculated from egg production, egg weight and feed consumption. Body weight gain was obtained by weighing all hens per replicate at the beginning and end of the experiment. Results of the experiment showed that egg production rate of hens consuming diets with threonine to lysine ratio of 78% were significantly higher than 66, 70 and 82% (P<0.05). Treatment with threonine to lysine ratio of 70% had the highest egg weight. Egg mass, feed intake and body weight gain were not influenced by dietary treatments. Feed conversion ratio of 78% treatment was lower than 66%. The highest and lowest sale income per Kg of egg was for 78 and 66% ratio respectively. Based on the results of this experiment, for maximum egg production rate and and profitability the Thr:Lys ratios was 78%.