Determination of Valine‏ ‏requirement for‏ ‏Ross 308 male broiler chickens ‎in grower period by using quadratic broken line regression

The aim of this experiment was to determine the digestible valine requirement of male Ross ‎‎308 broiler chicks in grower period. To evaluate valine requirement of male broiler chicks ‎based on growth performance, a total of 450one day old male broiler chicks from8 to 21days ‎of age, was assigned to 6 treatments with 5 replicate using a completely randomized design. ‎Dietary valine was supplied in 6 levels from 0.74, 0.79, 0.84, 0.89, 0.94 and 0.99for the ‎experimental period. Results of this study showed that the quadratic broken line model were ‎used for determine of digestible valine requirement for Ross 308 male broiler chicks is the well ‎fitted base on weight gain, feed conversion ratio and breast weight and Evaluated digestible ‎valine content for these three performance parameters were 0.93, 0.91 and 0.84 % of diet ‎‎(Val/lys were 88, 86 and 79%), respectively. The result of this experiment showed that the all ‎performance parameters and cell modified immune response were significantly affected by the ‎valine supplementation in diet (P< 0.01). The broiler chickens fed with 0.89 % of digestible ‎valine level had the highest cell modified immune response (1.13±0.05 mm) and the lowest ‎feed conversion ratio (1.42±0.02) (P<0.01), and also The broiler chickens fed with 0.74 % of ‎digestible valine level had the lowest cell modified immune response (0.44±0.03 mm) and the ‎highest feed conversion ratio (1.60±0.06). ‎