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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. [ABSTRACT FROM AUTHOR]

Essential amino acids such as methionine have been increasingly included into diets of lambs. However, few studies have determined the effects of methionine supplementation in the general performance and economic returns of lamb production. To address this question, 21 weaned male Rahmani lambs were allotted to 3 dietary treatments: control diet (C), control diet plus 3.30 g of methionine/kg concentrate feed mixture (T1), and control diet plus 3.63 g of methionine/kg concentrate feed mixture (T2). T1-fed lambs showed significantly higher (P<0.05) total body weight gain than those fed diets C. The digestibility coefficients of dry matter (DM), organic matter (OM), crude protein (CP), ether extract, (EE), and nitrogen free extract (NFE) for T1 and T2 were significantly better (P<0.05) than for C. Economically, dietary feed T1 and T2 increased the net profit by 329.64 Egyptian pounds EGP/lamb and 305.76 EGP/lamb, respectively, as compared with the control diet. In addition, the economic efficiency (average feed cost/kg of body weight gain) was 10.02 for C and T1 and 10.48 for T2. Total costs were similar between the 3 dietary treatments. In conclusion, feeding growing Rahmani lambs with 3.30 g of methionine/kg concentrate feed mixture improved their growth performance and raised their economic value. [ABSTRACT FROM AUTHOR]