Impacts of reduced-crude protein diets on key parameters in male broiler chickens offered maize-based diets

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

doi:10.3382/ps/pez573

Cited by 66 publications

(65 citation statements)

References 28 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: 59%

“…In theory, threonine may serve as a precursor of glycine when threonine is enzymatically converted to glycine and acetaldehyde by threonine aldolase [99,100] and there are also interconversions between serine and glycine in poultry [101]. As discussed, increases of 66% and 116% in free threonine plasma concentrations following reductions in dietary CP have been reported [39,40]. However, plasma concentrations of both glycine and serine declined following dietary CP reductions in the same two experiments.…”

Section: Threoninementioning

confidence: 81%

“…In this report, the transition from 183 to 159 g CP/kg diet diets increased free threonine concentrations in systemic plasma by 87% (1635 versus 876 nmol/mL) in female broiler chickens at 42 days post-hatch. Moreover, an increase in free threonine systemic plasma concentrations of 66% (1027 versus 619 µmol/L) at 34 days post-hatch following a reduction in dietary CP from 210 to 165 g/kg has been reported [39]. Similarly, an increase of 116% in plasma threonine (1093 versus 505 µmol/L) was observed pursuant to a dietary CP reduction from 200 to 156 g/kg [40].…”

Section: Threoninementioning

confidence: 86%

“…Additionally, these researchers indicated that the requirements for a methionine plus cysteine increase with increases in the dietary CP contents, which implies the reverse may be the case with reduced-CP diets. Certainly, the addition of 1.76 g/kg non-bound methionine to a 165 g CP/kg diet broiler diet did not influence growth performance in Chrystal et al [39]. However, enhanced utilisation of methionine in a reduced-CP diet (183 g CP/kg) compared to the standard protein diet (229 g/kg) offered to male broilers from 8 to 21 days post-hatch has been reported [140].…”

Section: Methioninementioning

confidence: 92%

“…However, CP reductions in maize-based diets have been shown to influence jejunal and ileal digestibility coefficients. A CP reduction from 210 to 165 g/kg increased the average jejunal digestibility of 16 amino acids by 29.4% (0.594 versus 0.459) [39] and the corresponding increase in ileal digestibility was 6.18% (0.790 versus 0.744). 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].…”

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

confidence: 97%

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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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