Effects of Feeding Regimens and Dietary Methionine Level on Growth Performance and Feather Growth of Meat Ducks from 29 to 49 Days of Age.

This study was conducted to evaluate the effects of feeding regimens and dietary methionine (Met) levels on the growth performance and feather growth of Cherry Valley ducks from 29 to 49 days of age. A 2 × 3 factorial arrangement was employed, consisting of two feeding regimens (ad libitum or "5+2" feed restriction: 5 days ad libitum + 2 days of fasting) and three levels of dietary Met (0.32%, 0.40%, or 0.48%). A total of 600 29-day-old male Cherry Valley ducks (initial body weight: 2.18 ± 0.12 kg) were randomly assigned to six treatment groups, with 10 replicates of 10 ducks each. Dietary Met as a main effect did not significantly influence growth performance > 0.05). The "5+2" feed restriction regimen reduced the 49-day final body weight, body weight gain, and feed intake (days 29-49) compared with ad libitum feeding, with a concurrent increase in the feed conversion ratio ( < 0.01). Body weight uniformity in the "5+2" feed restriction group was 4.33% higher than in the ad libitum group, though this difference was not statistically significant ( > 0.05). In addition, the feeding regimen tended to affect the feather weight and feather ratio, with the "5+2" regimen reducing the feather weight ( < 0.1) but increasing the feather ratio ( < 0.1) relative to ad libitum feeding. Higher dietary Met levels showed a tendency to improve the feather length and overall feather score < 0.1). A significant interaction was observed between the feeding regimen and Met level for wing feather length ( < 0.05). In conclusion, the "5+2" feed restriction impaired the growth performance and absolute feather yield in meat ducks. However, dietary Met levels interacted with feeding strategies to affect feather development. Specifically, under ad libitum feeding conditions, moderate-to-high Met supplementation (0.48% Met) appeared to be beneficial for feather yield, whereas lower Met levels (0.32% Met) were more effective for enhancing feather mass under restricted feeding. These findings highlight the potential to tailor Met supplementation according to feeding regimen to optimize both production and feather quality in ducks.