effects of different levels of lysine amino acid in arian broiler breeders diets on immunity and some blood biochemical traits

the aim of the present study was to determine the effects of different levels of lysine amino acid on immunity and some blood biochemical parameters of broiler breeder hens. the treatments were consisted of 6 levels of lysine (0.50, 0.57, 0.64, 0.71, 0.78 and 0.85%) and were used in a completely randomized design with 4 replicates and 8 hens in each pen from 52 to 64 weeks of their rearing period. the hens were selected according to the very nearly the same body weight (3600 ±15 g) for maximum uniformity in treatments groups. amino acids profile and composition of all diets were similar except of lysine levels. the results of physiological indicators showed that the different levels of dietary lysine had a significant effect on the blood serum albumin and total protein concentration (p<0.05). increasing lysine levels of diets to 0.64% was resulted in significant increase in antibody titer against sheep red blood cell(srbc), igm, serum albumin and total protein (p<0.05). an increased igg and blood serum globulin level were evident but were not significant. blood serum uric acid level not significantly affected by lysine. the results of cutaneous sensitivity to pha-p showed a not significant improvement in immune system. it is concluded that lysine had significant effects on immunity system, total protein and albumin so in estimating of requirement of lysine in broiler breeders in addition to production responses be immunity and physiological parameters must considered for optimal performance. in conclusion results of this study indicate that lysine needs may be higher than suggested by nrc (1994), especially in support of improved immunity and physiological characteristics.