Low-protein diets and crystalline amino acids support growth performance and carcass traits of growing Sansui sheldrake ducks

The study investigated the effects of reduced dietary crude protein (CP) on growth performance and carcass yield of Sansui sheldrake ducks. A dose-response experiment was conducted with 6 dietary CP levels (13.84, 14.43, 15.42, 16.33, 17.17, and 18.04%, analyzed), using crystalline amino acids to maintain a consistent amino acid profile. Male ducks were allotted to 6 experimental treatments with 7 replicate pens and 8 birds per pen, from 4 to 8 wk of age. Growth performance metrics, including weight gain, feed intake, feed conversion ratio (FCR), CP intake, and carcass traits, were evaluated at 8 weeks. Diet significantly affected (P < 0.05) among groups with CP levels between 14.43% and 18.04%. However, the lowest CP group (13.84% CP) had significantly lower weight gain and poorer FCR compared to the other groups. Additionally, abdominal fat yield of ducks fed a 13.84% CP diet was higher (P < 0.05) compared to all other groups (which did not differ). Regression analysis determined minimum CP requirements of 14.42% and 14.55% for optimal weight gain and FCR, respectively, from 4 to 8 weeks.