Apart from energy balance trials such as calorimetry,growth trials could also be used to estimate the energy values of feed ingredients with caloric efficiency as an indicator.Recent work used such methods reported gr...Apart from energy balance trials such as calorimetry,growth trials could also be used to estimate the energy values of feed ingredients with caloric efficiency as an indicator.Recent work used such methods reported greater net energy(NE)value of soybean meal(SBM)relative to corn in nursery pigs.We theoretically compared the NE values of SBM and corn according to the definition of NE and properties of the major chemical compositions in each ingredient.Meanwhile,we thoroughly examined the diet formulations and related analysis used in this work and compared this study with some peer works.We found that this study may suffer from problems with experimental design,reference citation,and data interpretation.In summary,the conclusion from the recent work that the SBM NE value may be greater than the corn NE value is likely to be erroneous.展开更多
Feed efficiency represents the cumulative efficiency with which the pig utilizes dietary nutrients for maintenance, lean gain and lipid accretion. It is closely linked with energy metabolism, as the oxidation of carbo...Feed efficiency represents the cumulative efficiency with which the pig utilizes dietary nutrients for maintenance, lean gain and lipid accretion. It is closely linked with energy metabolism, as the oxidation of carbon-containing components in the feed drive all metabolic processes. While much is known about nutrient utilization and tissue metabolism, blending these subjects into a discussion on feed efficiency has proven to be difficult. For example, while increasing dietary energy concentration will almost certainly increase feed efficiency, the correlation between dietary energy concentration and feed efficiency is surprisingly low. This is likely due to the plethora of non-dietary factors that impact feed efficiency, such as the environment and health as well as individual variation in maintenance requirements, body composition and body weight. Nonetheless, a deeper understanding of feed efficiency is critical at many levels. To individual farms, it impacts profitability. To the pork industry, it represents its competitive position against other protein sources. To food economists, it means less demand on global feed resources. There are environmental and other societal implications as well. Interestingly, feed efficiency is not always reported simply as a ratio of body weight gain to feed consumed. This review will explain why this arithmetic calculation, as simple as it initially seems, and as universally applied as it is in science and commerce, can often be misleading due to errors inherent in recording of both weight gain and feed intake. This review discusses the importance of feed efficiency, the manner in which it can be measured and reported, its basis in biology and approaches to its improvement. It concludes with a summary of findings and recommendations for future efforts.展开更多
Background:Two experiments were conducted to determine the effects of increasing amounts of soybean meal(SBM)in swine diets and estimate the energy value of SBM.Methods:A total of 2233 pigs(PIC 337×1050,Henderson...Background:Two experiments were conducted to determine the effects of increasing amounts of soybean meal(SBM)in swine diets and estimate the energy value of SBM.Methods:A total of 2233 pigs(PIC 337×1050,Hendersonville,TN)and 3796 pigs(PIC 359×C40),initially 11.0 kg and 17.6 kg body weight(BW),were used in Exp.1 and 2,respectively.In Exp.1,pigs were placed in 92 pens each containing 20 to 27 pigs.In Exp.2,pigs were placed in 84 pens each containing 37 to 43 pigs.Treatments were assigned in a randomized complete block design with BW as the blocking factor.Dietary treatments consisted of 21%,27%,33%,or 39%SBM in Exp.1 and 17.5%,22%,26.5%,31%,35.5%,or 40%SBM in Exp.2,obtained by changing the inclusion rate of feed-grade amino acids and corn grain.For Exp.1,representative samples of corn grain,SBM,and distillers dried grains with solubles were analyzed for total AA content prior to diet formulation.For Exp.2,diets were formulated using NRC(2012)nutrient loadings.Treatment diets were fed for 21 and 22 d(Exp.1 and 2)and there were 23 replicates in Exp.1 and 14 replicates in Exp.2.Pigs were weighed and feed disappearance measured weekly to calculate average daily gain(ADG),average daily feed intake(ADFI),gain-to-feed ratio(G:F),and caloric efficiency(CE).Data were analyzed with block as a random effect and treatment as a fixed effect,and contrasts were constructed to test the linear and quadratic effects of increasing SBM.Results:In Exp.1,there was a tendency(linear,P=0.092)for a decrease in ADFI as SBM increased.There was a tendency(P=0.090)for a quadratic response for ADG,with a decrease in ADG observed with 39%SBM inclusion.Pigs fed diets with increasing SBM had a tendency(quadratic,P=0.069)for an increase in G:F up to 33%SBM and an improvement(linear,P=0.001;quadratic,P=0.063)in CE with increasing SBM.Using CE to estimate the energy of SBM relative to corn,a value of 105.4%of corn energy or 2816 kcal/kg NE was determined using all data points.When removing the CE value of the 39%SBM treatment due to the quadratic tendency,SBM was estimated to have 121.1%of corn energy or 3236 kcal/kg NE.In Exp.2,there was a decrease(linear,P=0.001)in ADFI.Pigs fed increasing SBM had a tendency(linear,P=0.065)for reduced ADG but an improvement(linear,P=0.001)in G:F and CE as SBM increased.The energy value of SBM was estimated as 124.7%of corn energy or 3332 kcal/kg NE.Conclusions:The results suggest that feeding increasing levels of SBM improves G:F and CE.The energy value of SBM was estimated to be between 105%and 125%of corn,which is much greater than the NRC(2012)would indicate.展开更多
文摘Apart from energy balance trials such as calorimetry,growth trials could also be used to estimate the energy values of feed ingredients with caloric efficiency as an indicator.Recent work used such methods reported greater net energy(NE)value of soybean meal(SBM)relative to corn in nursery pigs.We theoretically compared the NE values of SBM and corn according to the definition of NE and properties of the major chemical compositions in each ingredient.Meanwhile,we thoroughly examined the diet formulations and related analysis used in this work and compared this study with some peer works.We found that this study may suffer from problems with experimental design,reference citation,and data interpretation.In summary,the conclusion from the recent work that the SBM NE value may be greater than the corn NE value is likely to be erroneous.
文摘Feed efficiency represents the cumulative efficiency with which the pig utilizes dietary nutrients for maintenance, lean gain and lipid accretion. It is closely linked with energy metabolism, as the oxidation of carbon-containing components in the feed drive all metabolic processes. While much is known about nutrient utilization and tissue metabolism, blending these subjects into a discussion on feed efficiency has proven to be difficult. For example, while increasing dietary energy concentration will almost certainly increase feed efficiency, the correlation between dietary energy concentration and feed efficiency is surprisingly low. This is likely due to the plethora of non-dietary factors that impact feed efficiency, such as the environment and health as well as individual variation in maintenance requirements, body composition and body weight. Nonetheless, a deeper understanding of feed efficiency is critical at many levels. To individual farms, it impacts profitability. To the pork industry, it represents its competitive position against other protein sources. To food economists, it means less demand on global feed resources. There are environmental and other societal implications as well. Interestingly, feed efficiency is not always reported simply as a ratio of body weight gain to feed consumed. This review will explain why this arithmetic calculation, as simple as it initially seems, and as universally applied as it is in science and commerce, can often be misleading due to errors inherent in recording of both weight gain and feed intake. This review discusses the importance of feed efficiency, the manner in which it can be measured and reported, its basis in biology and approaches to its improvement. It concludes with a summary of findings and recommendations for future efforts.
基金Financial support for this research from United Soybean Board,Chesterfield,MO,USA.
文摘Background:Two experiments were conducted to determine the effects of increasing amounts of soybean meal(SBM)in swine diets and estimate the energy value of SBM.Methods:A total of 2233 pigs(PIC 337×1050,Hendersonville,TN)and 3796 pigs(PIC 359×C40),initially 11.0 kg and 17.6 kg body weight(BW),were used in Exp.1 and 2,respectively.In Exp.1,pigs were placed in 92 pens each containing 20 to 27 pigs.In Exp.2,pigs were placed in 84 pens each containing 37 to 43 pigs.Treatments were assigned in a randomized complete block design with BW as the blocking factor.Dietary treatments consisted of 21%,27%,33%,or 39%SBM in Exp.1 and 17.5%,22%,26.5%,31%,35.5%,or 40%SBM in Exp.2,obtained by changing the inclusion rate of feed-grade amino acids and corn grain.For Exp.1,representative samples of corn grain,SBM,and distillers dried grains with solubles were analyzed for total AA content prior to diet formulation.For Exp.2,diets were formulated using NRC(2012)nutrient loadings.Treatment diets were fed for 21 and 22 d(Exp.1 and 2)and there were 23 replicates in Exp.1 and 14 replicates in Exp.2.Pigs were weighed and feed disappearance measured weekly to calculate average daily gain(ADG),average daily feed intake(ADFI),gain-to-feed ratio(G:F),and caloric efficiency(CE).Data were analyzed with block as a random effect and treatment as a fixed effect,and contrasts were constructed to test the linear and quadratic effects of increasing SBM.Results:In Exp.1,there was a tendency(linear,P=0.092)for a decrease in ADFI as SBM increased.There was a tendency(P=0.090)for a quadratic response for ADG,with a decrease in ADG observed with 39%SBM inclusion.Pigs fed diets with increasing SBM had a tendency(quadratic,P=0.069)for an increase in G:F up to 33%SBM and an improvement(linear,P=0.001;quadratic,P=0.063)in CE with increasing SBM.Using CE to estimate the energy of SBM relative to corn,a value of 105.4%of corn energy or 2816 kcal/kg NE was determined using all data points.When removing the CE value of the 39%SBM treatment due to the quadratic tendency,SBM was estimated to have 121.1%of corn energy or 3236 kcal/kg NE.In Exp.2,there was a decrease(linear,P=0.001)in ADFI.Pigs fed increasing SBM had a tendency(linear,P=0.065)for reduced ADG but an improvement(linear,P=0.001)in G:F and CE as SBM increased.The energy value of SBM was estimated as 124.7%of corn energy or 3332 kcal/kg NE.Conclusions:The results suggest that feeding increasing levels of SBM improves G:F and CE.The energy value of SBM was estimated to be between 105%and 125%of corn,which is much greater than the NRC(2012)would indicate.
