Two experiments were conducted to determine if the TSAA level suggested by the National Research Council (NRC) in 1984 was adequate for optimum performance of 3 to 6-wk-old broilers, and to assess the effect of added
copper on the TSAA requirement. A 2 x 3 x 2 factorial arrangement involving two
copper (0 and 240 ppm) and three TSAA levels (.72, .78 and .84%) and two sexes was used in each experiment.
Copper sulfate (CuSO4.5H2O) and DL-
methionine were the dietary supplements to pelleted diets. There were four groups of 20 males or 20 females in each experiment, housed in floor pens.
Methionine supplementation significantly improved
body weight gain and feed efficiency in males but not in females. A significant
copper x
methionine interaction was observed, with
methionine supplementation improving feed efficiency more in the presence of
copper than in its absence. Abdominal fat per unit of
body weight was significantly reduced by both
methionine and
copper in females but not in males. In a second experiment,
methionine significantly improved
body weight gain in males fed no added
copper and significantly reduced abdominal fat per unit of
body weight.
Methionine supplementation improved
body weight gain in males more in the absence than in the presence of
copper (significant TSAA x
copper interaction).
Methionine supplementation had no significant effects on performance of females in the second experiment, but
copper supplementation significantly improved feed efficiency.(ABSTRACT TRUNCATED AT 250 WORDS)