Re-estimation of supplemented methionine as total sulfur amino acid requirement for commercial male meat-type ducks

Abstract

The total sulfur amino acid (TSAA) requirements of commercial meat-type ducks were investigated by feeding diets supplemented with graded levels of DL-methionine (DL-met) compared with the standard recommendation for the strain during 3 growth phases. Five hundred male White Pekin ducklings were divided into 4 treatments, each of which consisted of 5 replicates (25 each) using a completely randomized design. From the birds aged 1-9 and 10-16 days, TSAA deficit diet significantly depressed growth rate and feed intake (P<0.05). During 10-16 days of age, the growth rate of the birds fed TSAA at 110% of the commercial requirement was faster than that of the 100% group, with the increase in growth rate and feed intake paralleling the TSAA intake (P<0.01). No significant effects of the TSAA level on productive performance of the birds from age 17-47 days were found. At the age of 47 days, increasing the TSAA levels up to 120% tended to decrease abdominal fat content (P=0.08), and significantly decreased blood uric acid concentration (P<0.01). There were no significant differences in carcass components and lipid profile in the serum. The TSAA level for optimum growth rate and FCR in commercial meat-type ducks is 100-110% of the recommended level for the strain, except during 10-16 days of age when 110% is recommended.