Effects of different methionine sources on growth performance, meat yield and blood characteristics in broiler chickens

Three graded levels of MHA (methionine hydroxyl analogue) added into the broilers' diets were based on the assumption that the relative bioavailability of MHA sources to DL-methionine (DLM) on a molar basis was 100%, 90% or 80% to meet the requirement of total sulphur amino acids. DLM was used as the reference control group. Live body weight at 21 and 35 days was retarded (p < 0.05) in chicks fed a diet containing 100% equivalent MHA-FA (methionine hydroxyl analogue free acid) across dietary treatments. Chicks fed the diet containing MHA-Ca vs. MHA-FA grew faster at 35 days (p < 0.05). Chicks consumed least (p < 0.05) when 100% equivalent MHA-FA was added during 1-21 days. FCR was enhanced in MHA-Ca (methionine hydroxyl analogue calcium salt) vs. MHA-FA at all days measured. MHA effect on mortality, being higher (p < 0.05) in chicks on MHA-FA vs. MHA-Ca, was noted. Serum concentration of total cholesterol was lowest (p < 0.05) in chicks fed on DLM-added diet, but highest (p < 0.05) in those fed 100% equivalent MHA-Ca. Serum concentration of immunoglobulin A was low (p < 0.05) in chicks fed on 100% or 80% equivalent MHA-Ca compared with the rest of treatments. Collectively, MHA-Ca performed better than MHA-FA as to performance traits.