The objective of this study was to in- vestigate the effect of dietary protein level on nitrogen retention and compare nitrogen metabolism in Lohm- ann Brown adult roosters and layers. The nitrogen ma- intenance requi...The objective of this study was to in- vestigate the effect of dietary protein level on nitrogen retention and compare nitrogen metabolism in Lohm- ann Brown adult roosters and layers. The nitrogen ma- intenance requirement （Nm ） was determined based on the nitrogen balance. Thirty Lohmann Brown adult roosters and 30 laying hens at 27 weeks of age were randomly divided into five groups of six birds per group. The birds were fed with one of five diets con- taining 10.46%, 11.77%, 13.79%, 16.77% or 18.29% of crude protein. Nitrogen intake, nitrogen retention and nitrogen retention efficiency were higher in roost- ers than in laying hens, and the average nitrogen re- tention rate for groups fed with CP level of 11.77%, 13.79%, 16.77% and 18. 29% was improved by9.14%. The nitrogen maintenance requirement for Lohmann Brown roosters and laying hens at 27 weeks of age were 0.4245 g/d and 0.5059 g/d, respective- ly, and Nm based on average body weight （BW） and metabolic body weight （ BW^Ts ） was 0.2364 g/kg BW and 0. 2739 g/kg BW~＇75 for laying hens and 0. 2754 g/kg BW and 0. 3208 g/kg BW^72 for roost- ers, respectively. The regression equations for daily N gain （NB, protein accretion） vs. daily N intake （NI ） for Lohrnann Brown layers and roosters were NB = 0.3743NI -0.1589（R2 =0.79） and NB =0.6228NI - 0.3151 （ R2 = 0.85 ）, respectively. The results of this study indicate that nitrogen intake and nitrogen reten- tion at the same dietary CP level were higher in roost- ers than in laying hens.展开更多
基金supported by the National System of Layer Producing Technology (nycytx-41)
文摘The objective of this study was to in- vestigate the effect of dietary protein level on nitrogen retention and compare nitrogen metabolism in Lohm- ann Brown adult roosters and layers. The nitrogen ma- intenance requirement （Nm ） was determined based on the nitrogen balance. Thirty Lohmann Brown adult roosters and 30 laying hens at 27 weeks of age were randomly divided into five groups of six birds per group. The birds were fed with one of five diets con- taining 10.46%, 11.77%, 13.79%, 16.77% or 18.29% of crude protein. Nitrogen intake, nitrogen retention and nitrogen retention efficiency were higher in roost- ers than in laying hens, and the average nitrogen re- tention rate for groups fed with CP level of 11.77%, 13.79%, 16.77% and 18. 29% was improved by9.14%. The nitrogen maintenance requirement for Lohmann Brown roosters and laying hens at 27 weeks of age were 0.4245 g/d and 0.5059 g/d, respective- ly, and Nm based on average body weight （BW） and metabolic body weight （ BW^Ts ） was 0.2364 g/kg BW and 0. 2739 g/kg BW~＇75 for laying hens and 0. 2754 g/kg BW and 0. 3208 g/kg BW^72 for roost- ers, respectively. The regression equations for daily N gain （NB, protein accretion） vs. daily N intake （NI ） for Lohrnann Brown layers and roosters were NB = 0.3743NI -0.1589（R2 =0.79） and NB =0.6228NI - 0.3151 （ R2 = 0.85 ）, respectively. The results of this study indicate that nitrogen intake and nitrogen reten- tion at the same dietary CP level were higher in roost- ers than in laying hens.
