Inclusions of non-bound amino acids particularly methionine,lysine and threonine,together with the"ideal protein"concept have allowed nutritionists to formulate broiler diets with reduced crude protein(CP)an...Inclusions of non-bound amino acids particularly methionine,lysine and threonine,together with the"ideal protein"concept have allowed nutritionists to formulate broiler diets with reduced crude protein(CP)and increased nutrient density of notionally"essential"amino acids and energy content in recent decades,However,chicken-meat production has been projected to double between now and 2050,providing incentives to reduce dietary soybean meal inclusions further by tangibly reducing dietary CP and utilising a larger array of non-bound amino acids.Whilst relatively conservative decreases in dietary CP,in the order of 20 to 30 g/kg,do not negatively impact broiler performance,further decreases in CP typically compromise broiler performance with associated increases in carcass lipid deposition.Increases in carcass lipid deposition suggest changes occur in dietary energy balance,the mechanisms of which are still not fully understood but discourage the acceptance of diets with reductions in CP,Nevertheless,the groundwork has been laid to investigate both amino acid and non-amino acid limitations and propose facilitative strategies for adoption of tangible dietary CP reductions;consequently,these aspects are considered in detail in this review.Unsurprisingly,investigations into reduced dietary CP are epitomised by variability broiler performance due to the wide range of dietary specifications used and the many variables that should,or could,be considered in formulation of experimental diets.Thus,a holistic approach encompassing many factors influencing limitations to the adoption of tangibly reduced CP diets must be considered if they are to be successful in maintaining broiler performance without increasing carcass lipid deposition.展开更多
Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis...Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis,and milk fatty acid(FA)output is sparse in sows.This study aimed to evaluate impacts of dietary fat levels and FA composition on these traits in sows.Forty second-parity sows(Danish Landrace×Yorkshire)were assigned to 1 of 5 dietary treatments from d 108 of gestation until weaning(d 28 of lactation):low-fat control diet(3%added animal fat);or 1 of 4 high-fat diets with 8%added fat:coconut oil(CO),fish oil(FO),sunflower oil(SO),or 4%octanoic acid plus 4%FO(OFO).Three approaches were taken to estimate de novo milk fat synthesis from glucose and body fat.Results Daily intake of FA was lowest in low-fat sows within fat levels(P<0.01)and in OFO and FO sows within highfat diets(P<0.01).Daily milk outputs of fat,FA,energy,and FA-derived carbon reflected to a large extent the intake of those.On average,estimates for de novo fat synthesis were 82 or 194 g/d from glucose according to method 1 or 2 and 255 g de novo+mobilized FA/d according to method 3.The low-fat diet increased mammary FAS expression(P<0.05)and de novo fat synthesis(method 1;P=0.13)within fat levels.The OFO diet increased de novo fat synthesis(method 1;P<0.05)and numerically upregulated mammary FAS expression compared to the other high-fat diets.Across diets,a daily intake of 440 g digestible FA minimized milk fat originating from glucose and mobilized body fat.Conclusions Sows fed diets with low-fat or octanoic acid,through upregulating FAS expression,increased mammary de novo fat synthesis whereas the milk FA output remained low in sows fed the low-fat diet or high-fat OFO or FO diets,indicating that dietary FA intake,dietary fat level,and body fat mobilization in concert determine de novo fat synthesis,amount and profiles of FA in milk.展开更多
Dietary protein(P)and carbohydrate(C)have a major impact on the sweet taste sensation.However,it remains unclear whether the balance of P and C influences the sweet taste sensitivity.Here,we use the nutritional geomet...Dietary protein(P)and carbohydrate(C)have a major impact on the sweet taste sensation.However,it remains unclear whether the balance of P and C influences the sweet taste sensitivity.Here,we use the nutritional geometry framework(NGF)to address the interaction of protein and carbohydrates on sweet taste using Drosophila as a model.Our results reveal that high-protein,low-carbohydrate(HPLC)diets sensitize to sweet taste and low-protein,high-carbohydrate(LPHC)diets desensitize sweet taste in both male and female flies.We further investigate the underlying mechanisms of the effects of two diets on sweet taste using RNA sequencing.When compared to the LPHC diet,the m RNA expression of genes involved in the metabolism of glycine,serine,and threonine is significantly upregulated in the HPLC diet group,suggesting these amino acids may mediate sweet taste perception.We further find that sweet sensitization occurs in flies fed with the LPHC diet supplemented with serine and threonine.Our study demonstrates that sucrose taste sensitivity is affected by the balance of dietary protein and carbohydrates possibly through changes in serine and threonine.展开更多
文摘Inclusions of non-bound amino acids particularly methionine,lysine and threonine,together with the"ideal protein"concept have allowed nutritionists to formulate broiler diets with reduced crude protein(CP)and increased nutrient density of notionally"essential"amino acids and energy content in recent decades,However,chicken-meat production has been projected to double between now and 2050,providing incentives to reduce dietary soybean meal inclusions further by tangibly reducing dietary CP and utilising a larger array of non-bound amino acids.Whilst relatively conservative decreases in dietary CP,in the order of 20 to 30 g/kg,do not negatively impact broiler performance,further decreases in CP typically compromise broiler performance with associated increases in carcass lipid deposition.Increases in carcass lipid deposition suggest changes occur in dietary energy balance,the mechanisms of which are still not fully understood but discourage the acceptance of diets with reductions in CP,Nevertheless,the groundwork has been laid to investigate both amino acid and non-amino acid limitations and propose facilitative strategies for adoption of tangible dietary CP reductions;consequently,these aspects are considered in detail in this review.Unsurprisingly,investigations into reduced dietary CP are epitomised by variability broiler performance due to the wide range of dietary specifications used and the many variables that should,or could,be considered in formulation of experimental diets.Thus,a holistic approach encompassing many factors influencing limitations to the adoption of tangibly reduced CP diets must be considered if they are to be successful in maintaining broiler performance without increasing carcass lipid deposition.
基金Financially supported by the Danish Council for Independent Research,Technology and Production Sciences (Copenhagen K,Denmark)。
文摘Background Dietary fat is important for energy provision and immune function of lactating sows and their progeny.However,knowledge on the impact of fat on mammary transcription of lipogenic genes,de novo fat synthesis,and milk fatty acid(FA)output is sparse in sows.This study aimed to evaluate impacts of dietary fat levels and FA composition on these traits in sows.Forty second-parity sows(Danish Landrace×Yorkshire)were assigned to 1 of 5 dietary treatments from d 108 of gestation until weaning(d 28 of lactation):low-fat control diet(3%added animal fat);or 1 of 4 high-fat diets with 8%added fat:coconut oil(CO),fish oil(FO),sunflower oil(SO),or 4%octanoic acid plus 4%FO(OFO).Three approaches were taken to estimate de novo milk fat synthesis from glucose and body fat.Results Daily intake of FA was lowest in low-fat sows within fat levels(P<0.01)and in OFO and FO sows within highfat diets(P<0.01).Daily milk outputs of fat,FA,energy,and FA-derived carbon reflected to a large extent the intake of those.On average,estimates for de novo fat synthesis were 82 or 194 g/d from glucose according to method 1 or 2 and 255 g de novo+mobilized FA/d according to method 3.The low-fat diet increased mammary FAS expression(P<0.05)and de novo fat synthesis(method 1;P=0.13)within fat levels.The OFO diet increased de novo fat synthesis(method 1;P<0.05)and numerically upregulated mammary FAS expression compared to the other high-fat diets.Across diets,a daily intake of 440 g digestible FA minimized milk fat originating from glucose and mobilized body fat.Conclusions Sows fed diets with low-fat or octanoic acid,through upregulating FAS expression,increased mammary de novo fat synthesis whereas the milk FA output remained low in sows fed the low-fat diet or high-fat OFO or FO diets,indicating that dietary FA intake,dietary fat level,and body fat mobilization in concert determine de novo fat synthesis,amount and profiles of FA in milk.
基金funded by the National Natural Science Foundation of China(31800993,31970934)Natural Science of Foundation of Guangdong,China(2018B030306002)Science and Technology Innovation Committee of Shenzhen,China(201908073000449)to Q.P.W。
文摘Dietary protein(P)and carbohydrate(C)have a major impact on the sweet taste sensation.However,it remains unclear whether the balance of P and C influences the sweet taste sensitivity.Here,we use the nutritional geometry framework(NGF)to address the interaction of protein and carbohydrates on sweet taste using Drosophila as a model.Our results reveal that high-protein,low-carbohydrate(HPLC)diets sensitize to sweet taste and low-protein,high-carbohydrate(LPHC)diets desensitize sweet taste in both male and female flies.We further investigate the underlying mechanisms of the effects of two diets on sweet taste using RNA sequencing.When compared to the LPHC diet,the m RNA expression of genes involved in the metabolism of glycine,serine,and threonine is significantly upregulated in the HPLC diet group,suggesting these amino acids may mediate sweet taste perception.We further find that sweet sensitization occurs in flies fed with the LPHC diet supplemented with serine and threonine.Our study demonstrates that sucrose taste sensitivity is affected by the balance of dietary protein and carbohydrates possibly through changes in serine and threonine.
