title: Estimation of the net energy requirement for maintenance in broilers.
abstract: OBJECTIVE
  The net energy requirement for the maintenance (NEm) of broilers was determined using regression models by the indirect calorimetry method (ICM) or the comparative slaughter method (CSM).
  
  
  METHODS
  A 2×4 factorial arrangement of treatments including the evaluation method (ICM or CSM) and feed intake (25%, 50%, 75%, or 100% ofad libitumrecommended) was employed in this experiment. In the ICM, 96 male Arbor Acres (AA) birds aged d 15 were used with 4 birds per replicate and 6 replicates in each treatment. In the CSM, 116 male AA birds aged d 15 were used. Among these 116 birds, 20 were selected as for initial data and 96 were assigned to 4 treatments with 6 replicate cages and 4 birds each. The linear regression between retained energy (RE) and metabolizable energy intake (MEI) or the logarithmic regression between heat production (HP) and MEI were used to calculate the metabolizable or net energy requirement for maintenance (MEm) or NEm, respectively.
  
  
  RESULTS
  The evaluation method did not detect any differences in the metabolizable energy (ME), net energy (NE), and NE:ME of diet, and in the MEI, HP, and RE of broilers. The MEI, HP, and RE of broilers decreased (p<0.01) as the feed intake decreased. No evaluation method× feed intake interaction was observed on these parameters. The MEmand NEmestimated from the linear relationship were 594 and 386 kJ/kg of body weight (BW)0.75/d in the ICM, and 618 and 404 kJ/kg of BW0.75/d in the CSM, respectively. The MEmand NEmestimated by logarithmic regression were 607 and 448 kJ/kg of BW0.75/d in the ICM, and were 619 and 462 kJ/kg of BW0.75/d in the CSM, respectively.
  
  
  CONCLUSIONS
  The NEmvalues obtained in this study provide references for estimating the NE values of broiler diets.
authors.affiliation: The key laboratory of feed biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: The key laboratory of feed biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Chang Hua
authors.initials: CH
authors.lastname: Lin
authors.affiliation: The key laboratory of feed biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Zheng Ke
authors.initials: ZK
authors.lastname: Wu
authors.affiliation: The key laboratory of feed biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Guo Hua
authors.initials: GH
authors.lastname: Liu
authors.affiliation: The key laboratory of feed biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Hai Jie
authors.initials: HJ
authors.lastname: Yan
authors.affiliation: Jilin Academy of Agricultural Sciences, Changchun 130124, China.
authors.forename: Hua Ming
authors.initials: HM
authors.lastname: Yang
authors.affiliation: The key laboratory of feed biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors.forename: Hui Yi
authors.initials: HY
authors.lastname: Cai
keywords: Broiler Maintenance Energy Requirement; Comparative Slaughter Method; Feed Intake; Heat Production; Indirect Calorimetry Method