Glycine equivalent and threonine inclusions in reduced-crude protein, maize-based diets impact on growth performance, fat deposition, starch-protein digestive dynamics and amino acid metabolism in broiler chickens

Chrystal, Peter V.; Moss, Amy F.; Yin, Dafei; Khoddami, Ali; Naranjo, Víctor; Selle, Peter H.; Liu, Sonia Yun

doi:10.1016/j.anifeedsci.2019.114387

Cited by 26 publications

(40 citation statements)

References 31 publications

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“…This example unequivocally demonstrates the potential synthetic and crystalline amino acids hold as alternatives to soybean meal in chicken-meat production and is supported by another recent study [37]. Nevertheless, CP reductions of this magnitude may compromise the efficiency of feed conversion with associated increases in fat deposition [38][39][40][41]. The genesis of compromised feed conversion ratios (FCRs) probably stems, at least partially, from an insufficiently accurate identification of essential and non-essential amino acid requirements, or ideal protein ratios, in the context of reduced-CP diets.…”

Section: Reduced-crude Protein Dietssupporting

confidence: 62%

“…The individual additions of either 1.10 g/kg non-bound threonine or 4.33 g/kg non-bound glycine equivalents to a 165 g CP/kg diet had little impact on broiler performance in Chrystal et al [41]. However, the combined inclusions of threonine and glycine equivalents displayed promise as they increased weight gain by 7.82% (2150 versus 1994 g/kg; p < 0.025) and decreased relative fat-pad weight by 12.5% (11.65 versus 13.31 g/kg; p < 0.01).…”

Section: Threoninementioning

confidence: 93%

“…The average jejunal digestibility of 16 amino acids increased by 9.38% (0.758 versus 0.693) following a dietary CP reduction from 200 to 156 g/kg, with an increase of 5.84% (0.797 versus 0.753) in the ileum [40]. However, the average ileal digestibility of 16 amino acids declined marginally by 1.65% (0.776 versus 0.789) pursuant to a CP reduction from 208 to 165 g/kg as opposed to a 7.95% (0.665 versus 0.616) increase in the jejunum [41]. Thus, the overall amino acid digestibility increased by 14.1% in the jejunum and more modestly by 3.41% in the ileum following a reduction in dietary CP from 206 to 162 g/kg across three studies.…”

Section: Impact Of Dietary Cp Reductions On Apparent Amino Acid Digesmentioning

confidence: 96%

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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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Section: Reduced-crude Protein Dietssupporting

confidence: 62%

Section: Threoninementioning

confidence: 93%

Section: Impact Of Dietary Cp Reductions On Apparent Amino Acid Digesmentioning

confidence: 96%

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

Selle

Dorigam

Lemme

et al. 2020

Animals

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“…Thus, additional threonine compromised responses to Gly equi . In contrast, Chrystal et al. (2020c) observed that in tangibly reduced CP (165 g/kg) maize-soybean meal diets, broiler growth performance was improved from the combined additions of threonine and glycine plus serine which was not the case when threonine or glycine plus serine were added individually to the reduced-CP diet.…”

Section: Amino Acid Considerationsmentioning

confidence: 84%

“…These researchers found a significant 6.18% increase (0.790 vs. 0.744) in average ileal amino acid digestibility coefficients pursuant to a reduction in dietary CP from 210 to 165 g/kg. However, in 3 consecutive assays ( Chrystal et al., 2020a , 2020b , 2020c ) increases in amino acid digestibilities were consistently observed following reductions in dietary CP of maize-based diets but the magnitude of these increases was variable. The most pronounced response was observed in Chrystal et al.…”

Section: Amino Acid Digestibilitymentioning

confidence: 97%

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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Maize-based diets are more conducive to crude protein reductions than wheat-based diets for broiler chickens

Chrystal

Greenhalgh

McInerney

et al. 2021

Animal Feed Science and Technology

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Glycine equivalent and threonine inclusions in reduced-crude protein, maize-based diets impact on growth performance, fat deposition, starch-protein digestive dynamics and amino acid metabolism in broiler chickens

Cited by 26 publications

References 31 publications

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

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

Maize-based diets are more conducive to crude protein reductions than wheat-based diets for broiler chickens

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