Effect of different levels of diet methionine and metabolisable energy on broiler performance and immune system

Chickens were chosen by a factorial 2×2 and random design. Methionine levels of 1.2 and 0.45% were adjusted to 2800 and 3200 kcal/kg metabolisable energy (ME) in starters and 0.9 and 0.33% to 2800 and 3200 kcal/kg ME in grower period, respectively. Antibody titres and IgG in chickens by 1.2 and 0.9% methionine were significantly higher than low levels of methionine. Significant increases of total leukocyte, percentage of lymphocytes and heterophils were observed in chickens fed by high methionine levels. Significant weight changes of bursa and spleen were found in this case at 42 days of age. Chicken body weights were significantly increased by a high level of methionine and low level of energy. Higher feed intake was obtained at high methionine and low energy. It is concluded that inclusion of high levels of methionine and energy in broilers diet have a beneficial effect on humoral immunity and performance.