Research Note Effect of Excess Methionine and Methionine Hydroxy Analogue on Growth Performance and Plasma Homocysteine of Growing Pekin Ducks

ABSTRACT One experiment was conducted to study the effect of excess DL-methionine (DLM) and DL-2-hy-droxy-4-methylthiobutanoic acid free acid (DL-HMB-FA) on duck growth. One-day-old male white Pekin ducklings were fed common starter diets from hatch to 21 d of age and then fed the experimental diets from 21 to 42 d of age. Three hundred twenty 21-d-old birds were allotted to 40 raised wire-floor pens with 8 birds per pen according to similar pen weight. There were 5 dietary treatments that included a methionine-adequate control diet and con-trol diets supplemented with 2 levels of dry DLM (1 or 2%) or 2 equimolar levels of liquid DL-HMB-FA (1.13 or 2.26%). Each dietary treatment was replicated 8 times. At 42 d of age, weight gain, feed intake, and gain/feed were measured and plasma was collected to analyze homocys-teine. Compared with ducks fed control diets, excess DL