In the past two decades, a considerable amount of research has focused on the determination of the digestible(DE) and metabolizable energy(ME) contents of feed ingredients fed to swine. Compared with the DE and ME sys...In the past two decades, a considerable amount of research has focused on the determination of the digestible(DE) and metabolizable energy(ME) contents of feed ingredients fed to swine. Compared with the DE and ME systems, the net energy(NE) system is assumed to be the most accurate estimate of the energy actually available to the animal. However, published data pertaining to the measured NE content of ingredients fed to growing pigs are limited. Therefore, the Feed Data Group at the Ministry of Agricultural Feed Industry Centre(MAFIC) located at China Agricultural University has evaluated the NE content of many ingredients using indirect calorimetry. The present review summarizes the NE research works conducted at MAFIC and compares these results with those from other research groups on methodological aspect. These research projects mainly focus on estimating the energy requirements for maintenance and its impact on the determination, prediction, and validation of the NE content of several ingredients fed to swine. The estimation of maintenance energy is affected by methodology, growth stage,and previous feeding level. The fasting heat production method and the curvilinear regression method were used in MAFIC to estimate the NE requirement for maintenance. The NE contents of different feedstuffs were determined using indirect calorimetry through standard experimental procedure in MAFIC. Previously generated NE equations can also be used to predict NE in situations where calorimeters are not available. Although popular, the caloric efficiency is not a generally accepted method to validate the energy content of individual feedstuffs. In the future,more accurate and dynamic NE prediction equations aiming at specific ingredients should be established, and more practical validation approaches need to be developed.展开更多
A comparative slaughter trial and a metabolism trial were conducted to determine the requirement of net energy （NE） and metabolizable energy （ME） by the crossbreed of German Mutton Merino×Inner Mongolia Merin...A comparative slaughter trial and a metabolism trial were conducted to determine the requirement of net energy （NE） and metabolizable energy （ME） by the crossbreed of German Mutton Merino×Inner Mongolia Merino for fattening from 35 to 50 kg of body weight （BW）. 49 crossbred female lambs （（33.9＋2.3） （SD） kg BW） of German Mutton Merino×lnner Mongolia Merino were used. 34 lambs were randomly chosen for comparative slaughter, which were offered an identical mixture diet （concentrate：roughage=55：45） at 100, 75 or 55% of ad libitum intake, whereas the remainders were used in the metabolism trial to evaluate the ME of the diet after methane production was measured by open-circuit respirometry. As feed intake decreased from 100 to 75 and 55% of ad libitum intake, the apparent digestibility of dry matter （DM） linearly increased （P=-0.010） from 60.8 to 63.6 and 66.9%, respectively, and methane production decreased from 52.1 to 44.3 and 39.9 L d-l, respectively, but the ratio of methane energy to gross energy intake increased linearly （P=0.010） from 8.20 to 8.96 and 10.97%, respectively. Consequently, the ME values of the diet increased from 9.35 to 9.64 and 9.85 MJ kg-~ DM, respectively. The NE requirement for maintenance （NEro） was 255 kJ kg-1 BW0.75, and the ME requirement for maintenance （MEre） was 352 kJ kg-I BW~.75, with a partial energy efficiency for maintenance （km） of 0.72. The NE requirement for growth （NEg） ranged from 1.26 to 4.66 MJ d-1as average daily gains increased from 100 to 300 g d-1, with a partial energy efficiency for growth （ks） of 0.45. These results indicated that the NEg required by crossbred female lambs of German Mutton Merinoxlnner Mongolia Merino was lower than the recommendation of the American or British nutritional system.展开更多
基金financially supported by the Modern Agricultural Industry Technology System(CARS-36)Developing key equipment for digital management and monitoring environment in animal production(2013AA10230602)+2 种基金National Natural Science Foundation of China(31372317)the 111 Project(B16044)China Postdoctoral Science Foundation
文摘In the past two decades, a considerable amount of research has focused on the determination of the digestible(DE) and metabolizable energy(ME) contents of feed ingredients fed to swine. Compared with the DE and ME systems, the net energy(NE) system is assumed to be the most accurate estimate of the energy actually available to the animal. However, published data pertaining to the measured NE content of ingredients fed to growing pigs are limited. Therefore, the Feed Data Group at the Ministry of Agricultural Feed Industry Centre(MAFIC) located at China Agricultural University has evaluated the NE content of many ingredients using indirect calorimetry. The present review summarizes the NE research works conducted at MAFIC and compares these results with those from other research groups on methodological aspect. These research projects mainly focus on estimating the energy requirements for maintenance and its impact on the determination, prediction, and validation of the NE content of several ingredients fed to swine. The estimation of maintenance energy is affected by methodology, growth stage,and previous feeding level. The fasting heat production method and the curvilinear regression method were used in MAFIC to estimate the NE requirement for maintenance. The NE contents of different feedstuffs were determined using indirect calorimetry through standard experimental procedure in MAFIC. Previously generated NE equations can also be used to predict NE in situations where calorimeters are not available. Although popular, the caloric efficiency is not a generally accepted method to validate the energy content of individual feedstuffs. In the future,more accurate and dynamic NE prediction equations aiming at specific ingredients should be established, and more practical validation approaches need to be developed.
基金conducted as part of the National Technology Program for Meat Sheep Industry of China (nycytx-39)funded by the Ministry of Agriculture of the People’s Republic of China
文摘A comparative slaughter trial and a metabolism trial were conducted to determine the requirement of net energy （NE） and metabolizable energy （ME） by the crossbreed of German Mutton Merino×Inner Mongolia Merino for fattening from 35 to 50 kg of body weight （BW）. 49 crossbred female lambs （（33.9＋2.3） （SD） kg BW） of German Mutton Merino×lnner Mongolia Merino were used. 34 lambs were randomly chosen for comparative slaughter, which were offered an identical mixture diet （concentrate：roughage=55：45） at 100, 75 or 55% of ad libitum intake, whereas the remainders were used in the metabolism trial to evaluate the ME of the diet after methane production was measured by open-circuit respirometry. As feed intake decreased from 100 to 75 and 55% of ad libitum intake, the apparent digestibility of dry matter （DM） linearly increased （P=-0.010） from 60.8 to 63.6 and 66.9%, respectively, and methane production decreased from 52.1 to 44.3 and 39.9 L d-l, respectively, but the ratio of methane energy to gross energy intake increased linearly （P=0.010） from 8.20 to 8.96 and 10.97%, respectively. Consequently, the ME values of the diet increased from 9.35 to 9.64 and 9.85 MJ kg-~ DM, respectively. The NE requirement for maintenance （NEro） was 255 kJ kg-1 BW0.75, and the ME requirement for maintenance （MEre） was 352 kJ kg-I BW~.75, with a partial energy efficiency for maintenance （km） of 0.72. The NE requirement for growth （NEg） ranged from 1.26 to 4.66 MJ d-1as average daily gains increased from 100 to 300 g d-1, with a partial energy efficiency for growth （ks） of 0.45. These results indicated that the NEg required by crossbred female lambs of German Mutton Merinoxlnner Mongolia Merino was lower than the recommendation of the American or British nutritional system.
