Effects of leucine supplementation on muscle protein synthesis and degradation pathways in broilers at constant dietary concentrations of isoleucine and valine

Zeitz, Johanna O.; Käding, Stella-Christin; Niewalda, Ines; Machander, Vlastislav; Dorigam, Juliano César de Paula; Eder, Klaus

doi:10.1080/1745039x.2019.1583519

Cited by 16 publications

(21 citation statements)

References 32 publications

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“…where leucine improved growth and retention of protein (Zhou et al, 2019), but similar to results reported for chicken (gallus gallus) fed increasing levels of leucine (Zeitz et al, 2019). This supports the hypothesis that the diets used seem to contain sufficient leucine to support growth and protein retention in Atlantic salmon.…”

Section: Discussionsupporting

confidence: 82%

Leucine did not stimulate growth and accretion in either stressed or unstressed Atlantic salmon

et al. 2021

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The branched-chain amino acids (BCAA) comprise leucine, valine and isoleucine, which all are indispensable for Atlantic salmon (Salmo salar) (NRC, 2011). All BCAA share some common properties including increased insulin secretion (Nair & Short, 2005). In addition, leucine plays a critical role in promoting growth by increasing protein synthesis and inhibiting protein degradation depending on mTOR being phosphorylated or not. When phosphorylated, the mTOR stimulates amino acid-sensing p70 S6 kinase (S6K1), eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and eukaryotic translation initiation factor 4E (eIF4E) and thus promotes protein synthesis

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Section: Discussionsupporting

confidence: 82%

Leucine did not stimulate growth and accretion in either stressed or unstressed Atlantic salmon

et al. 2021

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“…Alternatively, increasing digestible leucine concentrations from an average of 14.6 g/kg to 16.9 and 20.6 g/kg in starter, grower, and finisher maize-soy diets with an average CP content of 196 g/kg offered to broilers from 1 to 34 days post-hatch did not influence growth performance in Zeitz et al [122]. However, dietary concentrations of isoleucine and valine were kept constant in this study.…”

Section: Apparent Digestibility Coefficientmentioning

confidence: 83%

Synthetic and Crystalline Amino Acids: Alternatives to Soybean Meal in Chicken-Meat Production

Selle

Dorigam

Lemme

et al. 2020

Animals

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Simple Summary: There is a distinct possibility that synthetic and crystalline, or non-bound, amino acids will partially replace soybean meal in diets for broiler chickens and reduce the dependency of the chicken-meat industry on soybean meal as its principal source of protein.The genesis of this partial replacement will be the successful development of reduced-crude protein diets. A reduced-crude protein diet contains less soybean meal, and therefore less crude protein, but an increased array of essential and even non-essential non-bound amino acids so that requirements are met. There are, however, several challenges to be overcome if reduced-crude protein diets are to be successfully developed and adopted.Abstract: This review explores the premise that non-bound (synthetic and crystalline) amino acids are alternatives to soybean meal, the dominant source of protein, in diets for broiler chickens. Non-bound essential and non-essential amino acids can partially replace soybean meal so that requirements are still met but dietary crude protein levels are reduced. This review considers the production of non-bound amino acids, soybeans, and soybean meal and discusses the concept of reduced-crude protein diets. There is a focus on specific amino acids, including glycine, serine, threonine, and branched-chain amino acids, because they may be pivotal to the successful development of reduced-crude protein diets. Presently, moderate dietary crude protein reductions of approximately 30 g/kg are feasible, but more radical reductions compromise broiler performance. In theory, an 'ideal' amino acid profile would prevent this, but this is not necessarily the case in practice. The dependence of the chicken-meat industry on soybean meal will be halved if crude protein reductions in the order of 50 g/kg are attained without compromising the growth performance of broiler chickens. In this event, synthetic and crystalline, or non-bound, amino acids will become viable alternatives to soybean meal in chicken-meat production.Animals 2020, 10, 729 2 of 20 generates 1.1 kg CO 2 equivalents, which is considerably less than that of pork (3.8 kg CO 2 equivalents) or beef (14.8 kg CO 2 equivalents) production [2]. Moreover, it has been predicted that chicken-meat production will contribute 7.1% of greenhouse gas emissions compared to 29.8% and 63.1% for pork and beef, respectively [2]. However, diets for broiler chickens may contain more than 200 g/kg protein, the majority of which is derived from soybean meal; consequently, the chicken-meat industry has a huge demand for soybean meal. The production of 1 kg of chicken meat will require an input in the order of 560 g soybean meal given a conservative 250 g/kg dietary inclusion of soybean meal and a 2.25:1 conversion of feed into carcass weight. Importantly, this demand can be diminished by inclusions of non-bound (synthetic and crystalline) amino acids in broiler diets at the expense of soybean meal via the successful development of reduced-crude protein (CP) diets [3]. Therefore, synthetic...

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“…Despite the findings of Zeitz et al., 2019a , Zeitz et al., 2019b a potential imbalance of BCAA in reduced CP diets should be considered particularly when valine and isoleucine are at minimum dietary levels with correspondingly high leucine levels from maize protein. Whilst antagonism between the BCAA is unlikely to result in depressed broiler performance when practical type diets are offered this may not be the case with reduced-CP diets ( Waldroup et al., 2002 ).…”

Section: Amino Acid Considerationsmentioning

confidence: 97%

“…The hypothesis that dietary leucine, in excess of standard recommendations, increases protein synthesis and decreases protein degradation in broiler muscle was recently investigated in Ross 308 and Cobb 500 male broilers offered typical, standard 3 phase diets × 3 levels of BCAA to 34 and 35 d post–hatch respectively ( Zeitz et al., 2019a , 2019b ). In the Ross 308 study, the ratio of isoleucine:valine remained constant within each phase over the 3 diets investigated and leucine was incrementally increased by 22%, 15% and 11% in the starter, grower and finisher phases.…”

Section: Amino Acid Considerationsmentioning

confidence: 99%

Facilitating the acceptance of tangibly reduced-crude protein diets for chicken-meat production

et al. 2020

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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.

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Effects of leucine supplementation on muscle protein synthesis and degradation pathways in broilers at constant dietary concentrations of isoleucine and valine

Cited by 16 publications

References 32 publications

Leucine did not stimulate growth and accretion in either stressed or unstressed Atlantic salmon

Leucine did not stimulate growth and accretion in either stressed or unstressed Atlantic salmon

Synthetic and Crystalline Amino Acids: Alternatives to Soybean Meal in Chicken-Meat Production

Facilitating the acceptance of tangibly reduced-crude protein diets for chicken-meat production

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