Abstract: 【Objective】 The aim of this experiment was to study the effects of different dietary energy and protein levels on growth performance, body size traits, serum biochemical indices and slaughter performance of Xueshan breeding hens during brooding period, and to determine the appropriate dietary energy and protein levels during brooding period.【Method】 A total of 2 250 one-day-old Xueshan breeding hens with close body weight and good health were randomly divided into 9 groups with 3 energy levels (11.7, 11.9 and 12.1 MJ/kg) and 3 protein levels (18.0%, 19.0% and 20.0%) according to a 3×3 two-factor experiment design.Each group had 10 replicates and each replicate had 25 chickens.The experiment lasted for 42 days.Growth performance indicators were measured at the end of the test.Two chickens were selected for blood collection and one chicken was slaughtered for sampling, and serum biochemical indexes and slaughtering performance were measured.【Result】 ①Dietary energy level had significant effects on average daily feed intake (ADFI), average daily gain (ADG), ratio of feed to gain (F/G) and terminal weight of chicks (P<0.05).With the increase of energy level, ADFI and F/G showed a downward trend, while ADG and final body weight showed an upward trend, but evenness had no significant change(P>0.05).Dietary protein level had a significant impact on ADFI (P<0.05), which was decreased with the increase of protein level, but had no significant impact on other growth performance indicators(P>0.05).Dietary energy and protein levels had no significant interaction on growth performance indexes of chicks(P>0.05).②Dietary protein level had significant effects on keel length, serum triglyceride content and abdominal fat percentage of chicks (P<0.05), but had no significant effects on other body size indexes, serum biochemical indexes and slaughter performance indexes(P>0.05). Dietary energy level had no significant effect on the above indexes of chicks (P>0.05), and dietary energy and protein levels had no significant interaction on these indexes(P>0.05).【Conclusion】 Considering the growth performance, body size traits, serum biochemical indices and slaughter performance, it was recommended that the optimal level of dietary energy and protein for breeding hens of Xueshan breeding hens was 12.1 MJ/kg and 20.0%.

Key words: Xueshan chicken; brooding period; energy requirement; protein requirement