Different energy systems have been proposed for energy evaluation of feeds for domestic animals.The oldest and most commonly used systems take into account the fecal energy loss to obtain digestible energy(DE),and fec...Different energy systems have been proposed for energy evaluation of feeds for domestic animals.The oldest and most commonly used systems take into account the fecal energy loss to obtain digestible energy(DE),and fecal,urinary and fermentation gases energy losses to calculate metabolizable energy(ME).In the case of ruminants and pigs,the net energy(NE)system,which takes into account the heat increment associated with the metabolic utilization of ME,has progressively replaced the DE and ME systems over the last 50 years.For poultry,apparent ME(AME)is used exclusively and NE is not yet used widely.The present paper considers some important methodological points for measuring NE in poultry feeds and summarizes the available knowledge on NE systems for poultry.NE prediction equations based on a common analysis of three recent studies representing a total of 50 complete and balanced diets fed to broilers are proposed;these equations including the AME content and easily available chemical indicators have been validated on another set of 30 diets.The equations are applicable to both ingredients and complete diets.They rely primarily on an accurate and reliable AME value which then represents the first limiting predictor of NE value.Our analysis indicates that NE would be a better predictor of broiler performance than AME and that the hierarchy between feeds is dependent on the energy system with a higher energy value for fat and a lower energy value for protein in an NE system.Practical considerations for implementing such an NE system from the commonly used AME or AMEn(AME adjusted for zero nitrogen balance)systems are presented.In conclusion,there is sufficient information to allow the implementation of the NE concept in order to improve the accuracy of feed formulation in poultry.展开更多
This study evaluated the effect of multi-carbohydrase(MC)on energy and nitrogen(N)balance and gene expression in broilers fed diets with different crude protein(CP)contents.The study employed a 2×2 factorial arra...This study evaluated the effect of multi-carbohydrase(MC)on energy and nitrogen(N)balance and gene expression in broilers fed diets with different crude protein(CP)contents.The study employed a 2×2 factorial arrangement of treatments.The factors were presence or absence of MC,and standard(SCP)or low(LCP)dietary CP concentration.A 3-phase feeding program was used,including starter(0 to 7 d),grower(8 to 17 d)and finisher(18 to 28 d)phases.The study was undertaken in closed calorimetry chambers.Each of the 4 dietary treatments was replicated 8 times in total across 2 runs,with 2 birds per replicate(n=64).Data for energy partitioning and N balance were collected from d 25 to 28.On d 28,birds were euthanized to collect muscle and intestinal tissue samples for gene expression.The results showed that the MC increased apparent metabolizable energy(AME,P<0.01)and net energy(NE,P<0.05),and reduced the feed conversion ratio(FCR,P<0.01)in all diets.The proportion of energy retained as fat per total energy retention(REf/RE)was positively correlated with feed AME and NE(r=0.541,P<0.01 and r=0.665,P<0.001,respectively),suggesting that feed energy augmented with increased fat gain.Muscle ATP synthase subunit alpha(ATPSA1W)gene expression had a positive cor-relation with REf/RE and feed NE(r=0.587,P<0.001 and r=0.430,P<0.05,respectively).Similarly,muscle peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC-1A)expression was negatively correlated with weight gain and positively correlated with FCR(r-0.451,P<0.05 and r-0.359,P<0.05,respectively).These correlations show that over-expressions of muscle genes related to energy production reduce bird performance.This study demonstrated that MC increase dietary energy utilization,regardless of dietary CP concentration.However,the energy released by the enzymes in-creases feed energy-to-CP ratio,meaning there is excess energy that is then deposited as body fat.This suggests that supplemental MC in broiler feeds is beneficial if diets are formulated to contain marginal energy levels.展开更多
文摘Different energy systems have been proposed for energy evaluation of feeds for domestic animals.The oldest and most commonly used systems take into account the fecal energy loss to obtain digestible energy(DE),and fecal,urinary and fermentation gases energy losses to calculate metabolizable energy(ME).In the case of ruminants and pigs,the net energy(NE)system,which takes into account the heat increment associated with the metabolic utilization of ME,has progressively replaced the DE and ME systems over the last 50 years.For poultry,apparent ME(AME)is used exclusively and NE is not yet used widely.The present paper considers some important methodological points for measuring NE in poultry feeds and summarizes the available knowledge on NE systems for poultry.NE prediction equations based on a common analysis of three recent studies representing a total of 50 complete and balanced diets fed to broilers are proposed;these equations including the AME content and easily available chemical indicators have been validated on another set of 30 diets.The equations are applicable to both ingredients and complete diets.They rely primarily on an accurate and reliable AME value which then represents the first limiting predictor of NE value.Our analysis indicates that NE would be a better predictor of broiler performance than AME and that the hierarchy between feeds is dependent on the energy system with a higher energy value for fat and a lower energy value for protein in an NE system.Practical considerations for implementing such an NE system from the commonly used AME or AMEn(AME adjusted for zero nitrogen balance)systems are presented.In conclusion,there is sufficient information to allow the implementation of the NE concept in order to improve the accuracy of feed formulation in poultry.
基金The authors gratefully acknowledge Adisseo France for financial support of this study.
文摘This study evaluated the effect of multi-carbohydrase(MC)on energy and nitrogen(N)balance and gene expression in broilers fed diets with different crude protein(CP)contents.The study employed a 2×2 factorial arrangement of treatments.The factors were presence or absence of MC,and standard(SCP)or low(LCP)dietary CP concentration.A 3-phase feeding program was used,including starter(0 to 7 d),grower(8 to 17 d)and finisher(18 to 28 d)phases.The study was undertaken in closed calorimetry chambers.Each of the 4 dietary treatments was replicated 8 times in total across 2 runs,with 2 birds per replicate(n=64).Data for energy partitioning and N balance were collected from d 25 to 28.On d 28,birds were euthanized to collect muscle and intestinal tissue samples for gene expression.The results showed that the MC increased apparent metabolizable energy(AME,P<0.01)and net energy(NE,P<0.05),and reduced the feed conversion ratio(FCR,P<0.01)in all diets.The proportion of energy retained as fat per total energy retention(REf/RE)was positively correlated with feed AME and NE(r=0.541,P<0.01 and r=0.665,P<0.001,respectively),suggesting that feed energy augmented with increased fat gain.Muscle ATP synthase subunit alpha(ATPSA1W)gene expression had a positive cor-relation with REf/RE and feed NE(r=0.587,P<0.001 and r=0.430,P<0.05,respectively).Similarly,muscle peroxisome proliferator-activated receptor gamma coactivator 1 alpha(PGC-1A)expression was negatively correlated with weight gain and positively correlated with FCR(r-0.451,P<0.05 and r-0.359,P<0.05,respectively).These correlations show that over-expressions of muscle genes related to energy production reduce bird performance.This study demonstrated that MC increase dietary energy utilization,regardless of dietary CP concentration.However,the energy released by the enzymes in-creases feed energy-to-CP ratio,meaning there is excess energy that is then deposited as body fat.This suggests that supplemental MC in broiler feeds is beneficial if diets are formulated to contain marginal energy levels.
