Influence of protein and methionine concentrations and body size on the growth and carcase of muscovy ducks in the finishing stage of production

Methionine Requirements of Male White Peking Ducks from Twenty-One to Forty-Nine Days of Age

A dose-response experiment with 6 dietary methionine levels (0.20, 0.275, 0.35, 0.425, 0.50, and 0.575%) was conducted with male White Peking ducklings to estimate the methionine requirement of growing ducks from 21 to 49 d of age. One-day-old male White Peking ducklings were fed common starter diets from hatching to 21 d of age and then fed the experimental diets from 21 to 49 d of age. Three hundred thirty-six 21-d-old birds were allotted to 24 pens with 14 birds per pen according to similar pen weight. There were 6 dietary treatments, each containing 4 replicate pens. At 49 d of age, weight gain, feed intake, and feed/gain of ducks from each pen were measured, and 2 ducks selected randomly from each pen were slaughtered to evaluate the yields of abdominal fat, breast meat (including pectoralis major and pectoralis minor), and leg meat (including thigh and drum stick). Significant effects of dietary methionine on weight gain, breast meat, and abdominal fat were observed. Both weight gain and breast meat yield showed significant quadratic response to increasing dietary methionine, and abdominal fat decreased linearly (P < 0.05). According to the quadratic model, the optimal methionine requirement of male White Peking ducks from 21 to 49 d of age for maximum weight gain and breast meat yield were 0.377 and 0.379%, respectively.

Pearl millet in diets of white Pekin ducks

In two 21-d experiments, the performance, nutrient utilization, and carcass composition of ducks fed diets containing pearl millet were compared with those fed diets containing corn. Corn, in diets at two protein levels (22 vs 18% in Experiment 1 and 22 vs 16% in Experiment 2), was replaced by pearl millet either on an equal-weight or isonitrogenous basis. During the first 2 wk of the first experiment, corn diets compared on an isonitrogenous basis were superior (P < .05) to the millet diets in promoting weight gain (666 vs 633 g per duck) and feed consumption (965 vs 914 g per duck); but when compared on an equal-weight basis, the millet diets were similar to the corn diets in promoting growth. No significant differences were observed for weight gain, feed consumption, or feed efficiency at the end of 3 wk. Over the 21-d study, the higher protein diets were more efficiently (P < .05) converted to weight gain than the lower protein diets (.63 vs .60 g gain:g feed). Carcass protein in ducks fed the corn diets was greater (P < .05) than in those fed the pearl millet diets. In Experiment 2, growth performance differences across dietary protein levels were similar to those in Experiment 1. However in contrast to Experiment 1, feed consumption was similar for corn and pearl millet diets (776 vs 786 g per duck, respectively), and ducks fed the corn diets gained less (P < .05) than those fed the pearl millet diets (590 vs 622 g per duck) during the first 2 wk of Experiment 2. Results of the nutrient utilization trial conducted at the end of Experiment 2 revealed that diets containing pearl millet were higher (P < .05) in AME than those containing corn (3,300 vs 3,100 kcal/kg). These results indicate that pearl millet has a higher energy value and appears to be at least equal to corn in promoting weight gains in ducks.