Performance Hematology and Correlation between Economical Traits under the Effects of Dietary Lysine and Methionine in Broilers

Lysine (Lys) and Methionine (Met) as two primary essential amino acids and precursors of carnitine biosynthesis are involved in most of economical traits function in domestic animals. We assessed the impact of dietary Lys and Met on the performance, lipid redistribution, intramuscular fat, carcass quality and especially phenotypic correlations among some studied parameters in broiler chickens. 300 day- old male Ross 308 chicks were randomly divided among 5 treatments, with 4 replicates per treatment. There were 15 chicks in each replicate in a completely randomized design. Same basal diet was supplemented with 5 levels of synthetic Lys and Met in amount of 0, 10, 20, 30 or 40% higher than National Research Council (NRC), 1994 recommendation for starter and grower periods. The collected data were analyzed and determined the correlation coefficient by SAS software and Duncan's test was used to compare the means on a value of (P<0.05). The results indicated that the two highest levels of Lys and Met treatments (30 and 40% more than NRC recommendation) led to significant increase in carcass efficiency, European Production Efficiency Factor (EPEF), blood albumin, breast muscle, heart, spleen, lymphocytes and liver weight (P<0.05), whereas feed conversion ratio (FCR), crude fat contents of breast and thigh muscles and plasma triglyceride were the least in these two treatment groups (P<0.05). Statistical analysis also showed many numbers of significant (at levels of P<0.01 or P<0.05) positive or negative correlations between the studied traits. For example highly positive correlations between carcass efficiency with heart, liver, spleen and breast weights and negative correlations with FCR, abdominal fat, plasma triglyceride, heterophyles breast and thigh fat was observed. As a conclusion of present study, dietary Lys and Met in higher levels of NRC recommendation could influence the parameters relate to performance, fat distribution, carcass quality and immune system in broilers.