title: Estimation of the net energy requirements for maintenance in growing and finishing pigs.
abstract: The objective of this experiment was to determine the net energy requirements for maintenance of growing and finishing pigs using regression models. Thirty-six growing (27.38 ± 2.24 kg) and 36 finishing (70.25 ± 2.61 kg) barrows were used and within each phase. Pigs received a corn-soybean meal diet fed at 6 levels of feed intake, which were calculated as 0, 20, 40, 60, 80, or 100% of the estimated ad libitum ME intake (2,400 kJ ME/kg BW(0.6)·d(-1)) of the pigs. Measurements were conducted on 6 pigs per feeding level and per stage of growth. After a 5-d adjustment period, barrows in the fasted treatment were kept in respiration chambers for 2 d to measure the fasting heat production. Barrows in the other treatments were kept individually in respiration chambers for a 5-d balance trial followed by a 2-d fasting period. Heat production (HP) in the fed state was measured and feces and urine were collected in the balance trial. The total HP increased (P < 0.01) with increasing feeding levels. Fasting HP increased (P < 0.01) as previous feeding level increased and was less (P = 0.012) in finishing pigs than growing pigs if calculated per kilogram BW(0.6) per day. When using an exponential regression analysis, ME requirements for maintenance were estimated at 973 and 921 kJ/kg BW(0.6)·d(-1) and NE requirements for maintenance were estimated at 758 and 732 kJ/kg BW(0.6)·d(-1) for growing and finishing pigs, respectively. The efficiencies of using ME for growth and for maintenance were estimated at 66 and 78.7% for growing and finishing pigs, respectively. It is concluded that exponential regression between HP and a wide range of ME intake may be used as a new method to determine the NE requirement for maintenance.
authors.affiliation: State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, Beijing 100193, China.
authors.forename: G F
authors.initials: GF
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, Beijing 100193, China.
authors.forename: D W
authors.initials: DW
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, Beijing 100193, China.
authors.forename: F L
authors.initials: FL
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Animal Nutrition, Ministry of Agriculture Feed Industry Centre, China Agricultural University, Beijing 100193, China defali@public2.bta.net.cn.
authors.forename: D F
authors.initials: DF
authors.lastname: Li
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000818:Animals; D002153:Calorimetry, Indirect / Q000662:veterinary; D004032:Diet / Q000662:veterinary; D004734:Energy Metabolism / Q000502:physiology*; D008297:Male; D009584:Nitrogen / Q000378:metabolism; D009751:Nutritional Requirements / Q000502:physiology*; D013552:Swine / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology; D022722:Thermogenesis
chemical_list: D009584:Nitrogen
keywords: fasting heat production; growing–finishing pigs; indirect calorimetry; maintenance energy requirement