Effects of Adequate or Marginal Excess of Dietary Methionine Hydroxy Analogue Free Acid on Growth Performance, Edible Meat Yields and Inflammatory Response in Female Broiler Chickens

Two experiments were conducted to determine the effects of adequate or marginal excess of dietary DL-2-hydroxy-4-(methylthio) butanoic acid (MHA) on productive performance and inflammatory response induced by E. coli lipopolysaccharide (LPS). In first experiment, day-old-female chicks (Ross strain) were provided for 48 days with four experimental diets; (1) AB diet: a diet with antibiotics (AB) and DL-methionine (DLM) to meet the total sulfur amino acid (TSAA) requirements of broiler chickens, (2) DLM diet: the first diet without AB, (3) MHA diet: a diet supplemented with MHA in place of DLM of the diet 2 to meet the TSAA requirement, (4) excess MHA diet: a diet with 1.6 folds higher than the content of MHA in the MHA diet. All diets were formulated with ingredients of plant origin. There was no difference in growth performance among the dietary treatments. Edible meat yields in chicks fed the excess MHA diet were better than that in chicks fed the DLM or MHA diet. Chicks fed the excess MHA or MHA diet showed lower plasma ceruloplasmin and alpha-1 acid glycoprotein concentration following LPS injection than those fed the DLM diet at 23 days of age. The concentrations in chicks fed the excess MHA diet were comparable to those chicks fed the AB diet. In second experiment, 7-days -old female chicks were fed either of the DLM or MHA diet for 14 days. Chicks fed the MHA showed higher excreta dry matter content than chicks fed the DLM diet. Heterophil to lymphocyte ratio in blood after LPS injection was lower in chicks fed the MHA diet than that in chicks fed the DLM diet. These results suggest that marginal excess supplementation of MHA, in place of DLM, to diet improved meat production in female broiler chicks and dietary MHA has potential to alleviate certain stress responses.