The objective of this study is to study the effects of dietary intake levels on energy metabolism, carbon (C), and nitrogen (N) balance and to determine the maintenance requirements of energy and protein for male sika deer during their growing period. A total of 16 1-year-old male sika deer with similar body weight (BW) (63.25 ± 2.42 kg) were selected, with four animals per feed intake level. The feeding levels of the four groups for deer were 40, 60, 80, and 100% of the recommended amount, respectively. The nutrient digestibility and methane production were measured through digestion trials and respiratory trials. A 4 × 4 Latin Square design was performed in a respirometry trial. The results show that the apparent digestibility of C and N gradually increased as the level of feed intake decreased. Furthermore, with a decrease in feed intake level, the metabolic energy intake (MEI), heat production (HP), and retained energy (RE) of male sika deer significantly decreased (P < 0.01). The requirements of metabolic energy for maintenance (MEm) and net energy for maintenance (NEm) of growing deer are 251.17 and 223.62 kJ kg⁻¹BW^0.75d⁻¹, respectively, as estimated according to the logarithmic regression equations between HP and MEI. The net N requirement for maintenance (NNm) and net protein requirement for maintenance (NPm) of growing male sika deer based on the linear relationship between retained nitrogen (RN) and daily nitrogen intake (NI) were 251.8 mg kg⁻¹BW^0.75d⁻¹ and 1.57 g kg⁻¹BW^0.75d⁻¹, respectively. The NEm and NPm values obtained from this experiment fill the gap in net energy and protein requirements and serve as basic data for establishing the nutritional standards forsika deer breeding in China.

本研究的目的是研究膳食摄入水平对能量代谢、碳 (C) 和氮 (N) 平衡的影响，并确定雄性梅花鹿在生长期的能量和蛋白质维持需求。总共选择了 16 头体重 (BW) (63.25 ± 2.42 kg) 相似的 1 岁雄性梅花鹿，每个采食量水平 4 头。四组鹿的饲喂量分别为推荐量的40%、60%、80%和100%。通过消化试验和呼吸试验测量养分消化率和甲烷产量。在一项呼吸测量试验中进行了 4 × 4 拉丁方设计。结果表明，随着采食量的降低，C和N的表观消化率逐渐增加。此外，随着采食量的减少，磷< 0.01)。根据HP和MEI之间的对数回归方程估计，生长鹿的维持代谢能（MEm）和维持净能（NEm）的需求分别为251.17和223.62 kJ kg ^-1 BW ^0.75 d ^-1。基于保留氮 (RN) 和每日氮摄入量 (NI) 之间的线性关系，生长雄性梅花鹿的维持净氮需求 (NNm) 和维持净蛋白质需求 (NPm) 为 251.8 mg kg ^-1 BW ^0.75 d ⁻¹和 1.57 g kg ⁻¹ BW ^0.75 d ⁻¹， 分别。本试验获得的NEm和NPm值填补了净能量和蛋白质需要量的空白，为我国建立梅花鹿养殖营养标准提供了基础数据。