Starch and protein digestive dynamics in low-protein diets supplemented with crystalline amino acids

2017 ◽  
Vol 57 (11) ◽  
pp. 2250 ◽  
Author(s):  
S. Y. Liu ◽  
P. H. Selle

Digestive dynamics of starch and protein is defined as digestion of starch and protein, absorption of glucose and amino acids from the gut lumen and their transition across enterocytes to enter the portal circulation. Digestive dynamics consider the extent, rate and site of nutrient digestion along the small intestine and the bilateral, post-enteral bioavailability of glucose and amino acids. The underlying premise is that glucose and amino acids should be made available in appropriately balanced quantities at the sites of protein synthesis for efficient protein deposition and growth performance. Previous studies have suggested that feed conversion efficiency may be enhanced by rapidly digestible protein and that crystalline amino acids could be considered sources of ‘rapid protein’. At present, crystalline lysine, methionine and threonine are routinely included in broiler diets; moreover, an increasing array of both essential and non-essential crystalline amino acids is becoming commercially available. Despite unrestricted feed access in commercial chicken-meat production systems during the period of illumination, it appears that the intermittent feed consumption patterns of broiler chickens still provide scope for asynchronies in digestion and absorption of nutrients, which affects broiler performance. A better understanding of the post-enteral, bilateral bioavailability of glucose and amino acids in low-protein diets containing high levels of synthetic amino acids is clearly desirable and this applies equally to the relationship between crystalline and protein-bound amino acids.

Animals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 729 ◽  
Author(s):  
Peter H. Selle ◽  
Juliano Cesar de Paula Dorigam ◽  
Andreas Lemme ◽  
Peter V. Chrystal ◽  
Sonia Y. Liu

: 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.


2011 ◽  
Vol 49 (No. 10) ◽  
pp. 436-443 ◽  
Author(s):  
P. Zobač ◽  
I. Kumprecht ◽  
P. Suchý ◽  
E. Straková ◽  
J. Brož ◽  
...  

Two growth trials and a short-term metabolism trial were conducted in broiler chickens in the period of 22 to 42 days of age in order to evaluate the effects of two dietary levels of L-lactic acid (1.03 or 2.06 g/kg) and microbial 6-phytase (750 U/kg), added either separately or in combination, on growth rate, feed conversion, dressing percentage and utilization of selected nutrients. In the first growth trial, six different dietary treatments were added to a basal grower diet containing 19.4% crude protein and a reduced level of dietary phosphorus (P) (5.9 g total and 2.9 g non-phytate P per kg). Single administration of L-lactic acid did not show any positive effect on the growth rate or feed conversion. In contrast, phytase addition to a low-P grower diet resulted in the increased final weight of birds and higher feed conversion. This beneficial effect was markedly stronger when the microbial phytase was added to the diets containing L-lactic acid. Based on two-factor analysis of variance, microbial phytase significantly increased the mean final weight by 6.5% (P < 0.01) and significantly improved feed conversion from 1.877 to 1.829 (P < 0.05). In the second growth trial, the same six dietary treatments were added to a basal diet containing a standard level of dietary P (6.7 g total and 4.0 g non-phytate P per kg), but the level of crude protein was reduced to 17.0%. L-lactic acid alone did not show any positive effects on performance. Phytase supplementation alone resulted in numerical improvement of the final weight (+1.1–2.4%), but a higher effect was observed in the diets containing L-lactic acid. In agreement with the reduced final weights of broilers fed the low-protein diets, markedly higher values of feed/gain ratio were noted. In the metabolism trial, selected dietary treatments were involved to evaluate the effects of L-lactic acid and microbial phytase, added either separately or in combination, on the digestibility of nitrogen (N) and fat as well as on the retention and excretion of N and P. Apparent digestibility of N and fat in the low-P diets was not affected by dietary treatments. Retention and utilization of N were numerically higher in all treatments fed low-P diets when compared to the treatment fed a standard diet, but the differences were not significant. Retention of P was numerically higher in all treatments fed low-P diets. When compared to the standard diet, the combination of phytase and L-lactic acid increased daily P retention by 37.6%. P excretion was significantly (P < 0.05) reduced in all treatments fed low-P diets supplemented by both test products, either separately or in combination. A numerical decrease in N excretion was noted in both treatments fed low-protein diets.    


2021 ◽  
Vol 273 ◽  
pp. 02009
Author(s):  
Ivan Koschayev ◽  
Christina Mezinova ◽  
Nadezhda Sorokina ◽  
Antonina Ryadinskaya ◽  
Natalia Ordina ◽  
...  

One of the methods of combating unwanted microflora is the use of antibiotics, however, along with positive properties, they have a number of significant disadvantages, in particular, the detrimental effect of both pathogenic and beneficial intestinal microflora. In this regard, there is an urgent need to replace antibiotics with safer substances, which increasingly include probiotics. The mechanism of action of probiotics is to selectively affect pathogenic microflora, without harming the beneficial one. In the course of the study, it was found that low-protein diets (low in protein, but balanced in amino acid profile) allow unlocking the potential of probiotic cultures of the Bacillus amyloliquefaciens strain and, as a result, reduce feed conversion by 0.08 kg/kg.


2014 ◽  
Vol 59 (No. 1) ◽  
pp. 26-34 ◽  
Author(s):  
C.Y. Xie ◽  
G.J. Zhang ◽  
F.R. Zhang ◽  
S.H. Zhang ◽  
X.F. Zeng ◽  
...  

Optimum standardized ileal digestible (SID) tryptophan (Trp) to lysine (Lys) ratio was estimated for 67–96 kg barrows fed low protein diets supplemented with crystalline amino acids (AA). One hundred and fifty Yorkshire × Landrace barrows, with an average initial body weight (BW) of 67.3 ± 3.2 kg, were used in a 28-day feeding trial. All dietary treatments were based on corn, wheat bran, and soybean meal and were formulated to provide 10.5% crude protein and 12.6 MJ/kg metabolizable energy. The dietary SID Lys was set at 0.61% ensuring that Lys was marginally deficient for barrows of this weight range. Graded levels of crystalline l-Trp were added to the basal diet to produce diets providing SID Trp to Lys ratios of 0.131, 0.164, 0.197, 0.230, and 0.262. There were improvements in weight gain (linear and quadratic effect P < 0.01) and feed intake (linear effect P = 0.04) with increasing dietary SID Trp to Lys ratio. Increased SID Trp to Lys ratio resulted in a decrease in the serum urea nitrogen (SUN) content (linear and quadratic effect P < 0.01). The serum concentration of Trp increased with increasing dietary SID Trp to Lys ratio (linear effect P = 0.03, quadratic effect P = 0.08). Estimates of the optimum SID Trp to Lys ratios were 0.203, 0.197, and 0.214 for weight gain, feed conversion ratio, and SUN, respectively, using a broken-line model while a quadratic model produced optimum SID Trp to Lys ratios of 0.251, 0.224, and 0.249 for the same parameters. The results of this experiment indicate that the SID Trp to Lys ratio for finishing barrows is at least 0.203, which is higher than the SID ratio of Trp to Lys currently recommended by the National Research Council (NRC, 2012).


2020 ◽  
Vol 49 (6) ◽  
pp. 1047-1062
Author(s):  
S.H. Golzar Adabi ◽  
N Ceylan ◽  
İ Çiftci ◽  
A Ceylan

This experiment was conducted to determine the interaction effects that resulted from supplementation of low-protein diets with leucine (Leu), valine (Val), and glycine-glutamic acid (Gly-Glu) on growing broiler chicks from 11 to 24 days old. Two levels of digestible Leu (1.07 and 1.50%) and three levels of digestible Val (0.64, 0.74, and 0.84%) were investigated as a 2 × 3 factorial arrangement of treatments with 12 replicates. The diet with 1.07% digestible Leu and 0.84% digestible Val was supplemented with 0.34% Gly and 1.32% Glu as an additional treatment (T7). At 24 days old, 0.84% Val significantly improved feed conversion with 1.07% Leu, but 0.74% Val was sufficient with 1.50% Leu. The T7 diet further improved feed conversion. Increasing dietary Val from 0.64% to 0.74% significantly increased bone density and strength at the lower level of dietary Leu, while T7 significantly increased tibia breaking strength. There were significant Leu × Val interactions for villus height, crypt depth, and goblet cell numbers. Val at 0.84% maximized the development of the jejunum at the lower Leu level, while goblet cell number and crypt depth were impaired by increments of Val at the higher level of Leu. In conclusion, increasing the level of Val in low-protein grower diets significantly improved performance, bone and jejunum development of broilers, and its interaction with Leu was important. Therefore, these two amino acids (AAs) and the possibility of Gly-Glu fortification must be considered when formulating low-protein broiler diets. Keywords: bone traits, branched-chain amino acids, broilers, gut histology, performance


2018 ◽  
Vol 58 (9) ◽  
pp. 1625 ◽  
Author(s):  
Z. U. Rehman ◽  
J. Kamran ◽  
M. E. Abd El-Hack ◽  
M. Alagawany ◽  
S. A. Bhatti ◽  
...  

A 42-day experiment was conducted with 625 1-day-old male Hubbard chickens to evaluate the performance, carcass traits, nitrogen retention and economics of broiler chickens fed low protein and amino acid diets supplemented with different protease sources. Treatments included positive (PC) and negative (NC) controls (PC at 19.3% protein vs NC at 18.8% protein), with NC containing 7% less digestible amino acids. The other three treatment groups were based on the NC diet supplemented with 0.05% Cibenza® DP100 (CB), 0.02% Ronozyme® (RZ) or 0.02% Winzyme pro plus (WZ). Birds fed the PC, CB and WZ diets achieved the heaviest bodyweight compared with those fed the NC diet at end of the experiment. Total feed intake of birds fed the PC diet was higher (P < 0.05) than that of birds fed the NC diet. Feed conversion ratio was numerically significantly (P = 0.005) improved with all tested groups in comparison with NC throughout the experiment. European production index was similar (P > 0.05) among birds fed the PC, NC, RZ or WZ diets. All carcass parameters studied, including dressing, heart, gizzard, giblets, chest meat, thigh meat and abdominal fat percentages, were not significantly (P > 0.05) affected by feeding on the different sources of protease. Broilers fed the PC diet or diets formulated with all protease sources had higher (P < 0.05) nitrogen retention than did birds fed the NC diet. The supplementation of protease to low-protein and low-amino acid diets resulted in higher profit margin in broilers. It is concluded that supplementing exogenous protease to broiler diets containing low protein and amino acids improved the growth performance, feed utilisation, carcass traits, nitrogen retention and net returns of broiler chickens.


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