Effect of lysine level on growth performance, carcass characteristics, blood metabolites and breast muscle tissue of Ross 308 broilers

Abstract

Introduction: Lysine is the main essential amino acid required for muscle building in poultry
and preparation of accurate Lys requirements can greatly affect broiler performance and meat
yields.
Material & Methods: This study was carried out in a completely randomized design with 200
Ross broilers. Experimental treatments consisted of a Control diet with lysine requirement
based on Ross Aviagen Recommendation, a diet with 10% lower than lysine requirement, a
diet with 20% lower than lysine requirement, a diet with 10% more than lysine requirement
and a diet with 20% more than lysine requirement.
Results: The effect of treatments on feed intake was not significant. In the grower, finisher and
overall phase, increasing lysine level led to improved weight gain and feed conversion ratio
(P<0.05) and decreasing lysine level had a negative effect on growth performance. The relative
weight of carcass and breast increased by increasing lysine level (P<0.05), while the relative
weight of femur and other internal organs was unaffected. The effect of lysine level on blood
albumin, total protein and triglyceride was significant (P<0.05), but Uric acid was not affected.
Most muscle protein percent and area were observed in broilers fed by high levels of lysine.
Conclusion: These results imply that increasing lysine levels of diet 10 or 20% more than Ross
recommendation can improve growth performance, carcass and breast relative weight, muscle
protein percentage and histopathology of broilers.