Research On Energy And Protein Requirements Of 0 Wk～4 Wk Huaibei Ma Chicks

The experiment was conducted to examine the effects of dietary metabolizable energy and crude protein on growing performance, body composition, and deposition of energy and protein in 0 wk～4 wk Huaibei Ma chicks. The objective was to determine the requirements of energy and protein. Eight hundred and ten Huaibei Ma chicks 0f 1-d-old were assigned to 9 dietary treatments following a 4～wk experimental period. Nine dietary treatments were formulated to contain 11.9, 11.4 and 10.9 MJ/kg metabolizable energy and 19.00, 17.70, and 16.40% crude protein. At 2 wk and 4 wk, 3 chicks per stages were slaughtered to evaluate of the effects of dietary treatments on body composition, and deposition of energy and protein.Dietary metabolizable energy and crude protein, and interaction between energy and protein significantly affected growing performance, body composition, and deposition of energy and protein in 0 wk～4 wk Huaibei Ma chicks (P<0.05). Chicks fed low-ME-high-CP diet had lower feed intake than other dietary treatments (P<0.01). ADG was highest in chicks fed high-ME-high-CP, high-ME-normal-CP and low-ME-low-CP diets, and lowest in normal-ME and low-ME-high-CP diet (P<0.01). Chicks had higher feed efficient in high-ME-high-CP treatment (P<0.01).In general, it was similar tendency between 0～2 wk and 0～4 wk as measured body composition. Chicks fed medium-ME-medium-CP diet have lowest body energy concentration, and have highest body energy concentration in high-ME-medium-CP diet (P<0.01). Body fat percent was higher in high-ME-low-CP treatment than others (P<0.01). Chicks fed high-ME-low-CP and low-ME-low-CP diet have highest energy deposition efficiency, and lowest in medium-ME-medium-CP treatment (P<0.01). Chicks have highest nitrogen deposition efficiency in high-ME-medium-CP treatment in 0～2 wk and low-ME-low-CP diet in 0～4 wk, and lowest in medium-ME-medium-CP dietary treatment (P<0.01). There were not increases in nitrogen deposition efficiency as energy increased in low CP diet and as CP increased in low energy diet.Regressing analysis showed a quadratic increase in growing performance, feed efficiency and energy deposition as dietary energy increased, and minimum would be reached when dietary energy was 11.40 MJ/kg. Effect significant was larger using the ratio of energy to CP (EPR) than dietary ME and CP level. A quadratic increase in ADG and feed efficiency...