Effect of added dietary lysine and methionine above recommended levels, on growth performance, breast meat yield and financial returns in broilers

This study investigated the effect of added lysine and methionine above recommended levels in broiler diets, on their growth, breast meat yield and financial returns. A total of 175 one-day-old Cobb 500 chicks were assigned to seven dietary treatments in a completely randomized design. Treatment one (T1) was a control diet formulated to breed specifications. Treatments two (T2) and three (T3) contained 1.2 times recommended levels of Lys and Met respectively. Treatment four (T4) contained Lys and Met at 1.2 times recommended levels. Treatments five (T5) to seven (T7) had similar combinations of Lys and Met as T2 to T4 but their inclusions were 1.4 times recommended levels. On day 43 five birds per treatment were slaughtered for breast meat yield measurements. Broilers on T6 had heavier (P<0.05) breast meat (691.6 g) and tenderloin weights (126.4 g) compared to birds on T1 (491.2 and 93.8 g respectively). The premium on the price of breast meat more than offset the added feed cost of the nutrient dense diets. However, if the finished dressed broilers are to be sold whole and uncut, this trial showed that it is better to feed the birds at the manufacturers recommended levels of Lys and Met. Keywords: Lysine; Methionine; Broilers; Breastmeat; Financial analysi