Standardized ileal digestibility of amino acids of protein sources associated with exogenous enzymes for broilers

Article information

Anim Biosci. 2022;35(7):1030-1038
Publication date (electronic) : 2022 January 5
doi : https://doi.org/10.5713/ab.21.0416
1Federal Institute of Education, Science and Technology Goiano, Iporá, 76200-000, Brazil
2Department of Animal Science, Federal University of Goiás, Goiás, 74690-900, Brazil
*Corresponding Author: Bruno Duarte Alves Forte, Tel: +55-62-98400-0900, E-mail: bruno.fortes@ifgoiano.edu.br
Received 2021 September 11; Revised 2021 October 27; Accepted 2021 December 12.

Abstract

Objective

Two experiments were conducted to evaluate the effect of enzyme complex (EC) on the standardized ileal digestibility (SID) of amino acids (AA) in corn gluten meal (60%) (CGM), soy protein concentrate (SPC), dried bovine plasma (DBP), and poultry offal meal (POM). Experiments I and II were conducted with broilers in the pre-starter (1 to 7 days of age) and starter (1 to 21 days of age) phases, respectively.

Methods

The treatments consisted of a protein-free diet (PFD) containing feedstuffs either supplemented with EC (xylanase, amylase, and protease) or not. In Experiment I, a total of 360 one-day-old male Cobb-500 broiler chicks were randomly housed in 45 pens, resulting in five replicates with eight birds each, totalizing eight treatments and one PFD group. In Experiment II a total of 270 one-day-old male Cobb-500 broiler chicks were randomly housed in 45 pens, resulting in five replicates with six birds each, totalizing eight treatments and one PFD group. The PFD groups were used to assess the endogenous AA losses. The birds were slaughtered to collect the ileal content.

Results

In the pre-starter phase, the SID of arginine, branched chain-aminoacids, glycine, serine, aspartate, and glutamic acid increased with EC addition. The EC improved the SID of arginine and glutamic acid of CGM; the SID of valine and cystine of SPC; the SID of leucine, glycine, and aspartate of POM and the SID of isoleucine of DBP. In the starter phase, the SID of isoleucine, phenylalanine and glycine increased in EC-supplemented diets. The EC improved the SID of isoleucine of DBP; the SID of phenylalanine of CGM and POM. The SID of AA of SPC was not influenced by the EC.

Conclusion

The addition of an EC to broiler pre-starter and starter diets is efficient in increasing the SID of AA on SPC, POM, and DBP.

INTRODUCTION

Alternative ingredients to corn and soybean meal have been used in broiler diets in the poultry industry; however, knowledge of the AA digestibility of these foods is a concern among nutritionists. Several factors are believed to affect AA digestibility, such as the bioassay and animal age [1], ingredient origin [2], the timing of planting and harvesting [3], a fermentation process of the ingredients [4] and exogenous enzyme complex (EC) [5,6].

The use of enzymes in their mono-component form or combined in blends is routine practice in poultry feeding. The efficacy of exogenous protease on AA digestibility in broiler diets that contain both xylanase and phytase was verified by [6]. Xylanase is effective to improve the ileal amino acid (AA) digestibility in broiler chickens [7]. Enzyme complexes such as xylanase, amylase and protease may be used in broilers’ diets, aiming to increase their performance and nutrient digestibility [8]. This better performance can be attributed to an enhancement of nutrient digestibility, including AA digestibility.

Different effects of the enzyme are observed according to the developmental stages of the birds. In young broilers, this is even more significant, since major differences in physiological development will impact their development throughout life [9,10]. In addition, it has been reported that bird age per se is a factor that affects AA digestibility of ingredients [1]. For this reason, the quality of ingredients and meeting the requirement of AAs for broilers in the pre-starter and starter phases of life is important to ensure their slaughter weight.

The main protein source for broilers is soybean meal. However, to reduce the diet costs, alternative by-products and an EC can be used. It was demonstrated that a multi-carbohydrase and phytase complex allows a saving in feed cost while guaranteeing the same performance of the broilers [11]. Corn gluten meal, soy protein concentrate (SPC), dried bovine plasma (DBP) and poultry offal meal (POM) provide a higher protein content and are commonly used in non-ruminant diets. The dietary AAs affect the body weight gain, the growth rate, the feed conversion ratio, the internal organ development [12], and the function of the gastrointestinal tract of broilers [13]. Therefore, the EC is used in diets to improve the digestibility of the AAs in by-products. Some authors concluded that feeding a combination of multi-carbohydrase and phytase results in higher standardized ileal digestibility (SID) of arginine, histidine, methionine, and threonine relative to a single activity in canola meal [14].

The present study was conducted to evaluate the effect of EC on the SID of AAs in CGM (60%), SPC, DBP, and POM to broiler pre-starter and starter diets.

MATERIALS AND METHODS

Animal care and study site

The experiments were conducted on the poultry facilities at the Department of Animal Science of the Federal University of Goiás (UFG), Brazil. Experimental protocols received approval from the Ethics Committee on Animal Use of UFG (case no. 066/12).

Animals, experimental design

Two experiments were carried out to assess the SID of AA in CGM (60%), SPC, DBP, and POM with an EC or not, for broilers in the pre-starter (1 to 7 days of age, Experiment I) and starter phase (1 to 21 days of age, Experiment II).

In both experiments, a group of broilers were fed a pro tein-free diet (PFD) to assess the endogenous losses of AAs and calculate the SID of AAs.

In Experiment I, a total of 360 one-day-old male Cobb- 500 broiler chicks from a commercial hatchery were randomly housed in 45 pens, resulting in five replicates with eight birds each in the pre-starter phase, totalizing eight treatments and one PFD group.

In Experiment II a total of 270 one-day-old male Cobb- 500 broiler chicks from a commercial hatchery were randomly housed in 45 pens, resulting in five replicates with six birds each in the starter phase, totalizing eight treatments and one PFD group.

Experimental diets

The experimental diets included four protein sources: CGM, SPC, DBP, and POM, which were each supplemented with EC or not, totalizing eight treatments.

The experimental diets were made with the inclusion of feedstuff to replace the cornstarch of PFD. CGM and SPC replaced 20% of the cornstarch in the diet. DBP and POM replaced 17% of the cornstarch in the diet (Table 1). The EC (Axtra) contained (per kg) 2,000 U xylanase, 200 U amylase and 4,000 U protease. Enzyme addition followed the manufacturer recommendations. The acid-insoluble ash Celite was included at 1% as an indigestible marker for calculating standardized AA digestibility [15]. The birds were allowed a period of five days of adaptation to the experimental diets. Water and feed were available ad libitum throughout the experimental period.

Ingredient composition of the experimental diets fed to broilers, as fed-basis (%) (Experiment I and II)

The dry matter (DM), crude protein (CP) contents and the total AA composition of the analyzed feedstuffs are described in Table 2.

Dry matter, crude protein contents and total amino acid composition of different feedstuffs for broiler, expressed in percentage (as-fed basis)1)

Broiler management

From one to seven (Experiment I) and one to 21 days of age (Experiment II), the chicks were raised in five broiler battery galvanized steel cages equipped with trough-type feeders and drinkers. Each battery contained five floors with 0.33×0.50 m divisions. To heat the birds, 40-watt incandescent lamps were used for each battery floor until the birds completed 7 and 14 days of age, in Experiments I and II, respectively. The broilers were managed according to the management guidelines of the line. Ambient temperature and relative humidity were recorded daily, and adequate curtain management was adopted.

Ileal content sample collection

At seven (Experiment I) and 21 (Experiment II) days of age, all birds from all replicates were slaughtered by cervical dislocation and immediately dissected at 5 cm from the ileocecal-colic junction to 40 cm towards the jejunum for ileal content collection and determination of endogenous AA losses, following Sakomura and Rostagno [15] recommendations.

The ileal content was packed in plastic bags, labelled, and stored in a freezer at −16°C. Samples of ingredients, diets and ileal contents were vacuum-freeze-dried at a temperature of −40°C for 72 hours and sent to the Animal Nutrition Laboratory at EVZ/UFG for processing and analysis of the DM and CP contents of feedstuffs and ileal content. The DM content was determined by drying in an oven (105°C), the CP by the micro-Kjeldahl method (nitrogen distiller Tecnal TE-0364; Tecnal Industry Trade Import and Export of Scientific Laboratory Equipment, Piracicaba, SP, Brazil). The analysis was determined according to the procedures described by Silva and Queiroz [16]. To determine the total AA content, high performance/pressure liquid chromatography was performed at the Laboratory of Evonik Industries (Hanau, Germany).

Calculations

The SID of AAs was calculated according to the proposal equations from Sakomura and Rostagno [15], as follow:

AID (%)=[(Aadiet [DM,%]/AIAdiet [%])-(AA ileal digesta [%]/AIA ileal digesta [%])]×100/AA diet (DM,%)/AIAdiet (%)
EAA (g/kg DM)=AA digesta (g/kg DM)×[AIA diet (g/kg DM)/AIA digesta (g/kg DM)]
SID (%)=AID (%)+[EAA (g/kg DM)/AA digt (g/kg DM)]×100

in which: AID, apparent ileal digestibility of the AA; AIA, acid-insoluble ash; SID, standardized ileal digestibility of AA; DM, dry matter; EAA, basal endogenous AA loss.

The standardized AA content of feedstuffs was calculated according to the total AA content and the SID and presented as a fed basis.

Statistical analysis

The data were subjected to analysis of variance, and to mean comparison by the Scott Knott test at the 5% significance level, using the R statistical program, R Core Team 2021. The statistical model included the fixed effects of feedstuffs and EC supplementation, and their interaction effect, and the random effects of the experimental unit. Data were analyzed within each feedstuff by analysis of variance to test the effects of EC within each ingredient. A multivariate analysis of principal components was performed to assess the interrelationships between variables and treatments.

RESULTS

The SID of AA in CGM (60%), SPC, DBP, and POM, determined with broilers at seven days of age, are described in Table 3. There were verified differences in SID of all AA according to the feedstuffs. The SPC presents a higher SID of AA. However, the SID of lysine, methionine, histidine, alanine, and aspartate were similar between the CPS and the DPB. The CGM presents the lowest SID of methionine, methionine plus cystine, threonine, arginine, histidine, leucine, phenylalanine, serine, alanine, and glutamic acid. The SID of arginine, branched chain-aminoacids, glycine, serine, aspartate, and glutamic acid increased with EC addition (Table 3).

Standardized ileal digestibility of amino acids (%) of feedstuffs determined in seven-day-old broilers

The SID of AA within each feedstuff with or without EC in pre-starter diets is shown in Table 4. The SID of arginine and glutamic acid of CGM increased with EC addition. It was observed that the SID of valine and cystine of SPC were higher with EC inclusion. The POM presented a higher SID of leucine, glycine, and aspartate when the EC was used. The SID of isoleucine of DBP increased with EC inclusion.

Standardized ileal digestibility of amino acids (%) of feedstuffs with or without enzyme complex in seven-day-old broilers

The SID of AA in feedstuffs determined with broilers at 21 days of age is described in Table 5. It was observed, unlike what occurred in seven days old, that the SID of some AA of SPC, DBP and CGM were similar (methionine, cystine, methionine plus cystine, threonine, valine, serine, proline, glutamic acid), indicating better utilization of AAs of alternative feedstuffs with increased age. Furthermore, the lowest SID of indispensable AA in POM was verified. The SID of isoleucine, phenylalanine and glycine increased with EC addition in the broiler starter diet (Table 5).

Standardized ileal digestibility of amino acids (%) of feedstuffs determined in 21-day-old broilers

The SID of AAs (%) of each feedstuff with or without EC on starter diets of broilers is described in Table 6. The EC improved the SID of phenylalanine of CGM. The SID of AA of SPC was not influenced by the EC in diets. The DBP presents a higher SID of isoleucine when the EC was used.

Standardized ileal digestibility of amino acids (%) of feedstuffs with or without enzyme complex in 21-day-old broilers

The standardized AA contents of the analyzed feedstuffs are described in Table 7. Although the feedstuffs studied are protein sources, the contents of AA in each presented great variation.

Standardized digestible amino acid contents of feedstuffs (%) (as-fed basis)1)

The results of multivariate analysis are presented in Figure 1 and 2 of the pre-starter and starter phases, respectively. It was observed that the SID of AA of SPC with or without an EC was higher than the SID of AA of CGM, DBP and POM at the pre-starter and starter phases. In the pre-starter phase, we verified that the CGM shows the lowest SID of AA, however, at the starter phase the POM shows the lowest SID of AA (Figure 1). There was no negative correlation between the SID of AA to feedstuffs studied, but there was a clear positive correlation between the SID of some AA studied, such as proline and serine in the pre-starter phase. At the starter phase, the SID of phenylalanine, isoleucine and cystine showed no correlation (Figure 2).

Figure 1

2D plot generated by principal component analysis. The graph shows a separation between the feedstuffs with or without the enzyme complex and their relationship to the standardized ileal digestibility (SID) of amino acids (AA), based on multivariate analysis in pre-starter phase. CGM, corn gluten meal; CGM_EC, corn gluten meal with enzyme complex; SPC, soy protein concentrate; SPC_EC, soy protein concentrate with enzyme complex; POM, poultry offal meal; POM_EC, poultry offal meal with enzyme complex; DBP, dried bovine plasma; DBP_EC, dried bovine plasma with enzyme complex.

Figure 2

2D plot generated by principal component analysis. The graph shows a separation between the feedstuffs with or without the enzyme complex and their relationship to standardized ileal digestibility (SID) of amino acids (AA), based on multivariate analysis in starter phase. CGM, corn gluten meal; CGM_EC, corn gluten meal with enzyme complex; SPC, soy protein concentrate; SPC_EC, soy protein concentrate with enzyme complex; POM, poultry offal meal; POM_EC, poultry offal meal with enzyme complex; DBP, dried bovine plasma; DBP_EC, dried bovine plasma with enzyme complex.

DISCUSSION

The aim of this study was to evaluate the effect of EC on the SID of AA of four protein sources in pre-starter and starter broilers’ diets. Knowledge of the AA digestibility of feed ingredients is of great importance, especially when aiming to use an unconventional feedstuff in broiler diets. In the present study, it was verified that in the pre-starter phase the SID of arginine, branched chain-aminoacids, glycine, serine, aspartate, and glutamic acid was increased in EC-supplemented diets. In contrast, at the starter phase, only the SID of isoleucine, phenylalanine and glycine increased with EC addition to the diet. This improvement occurred independently of the feedstuff studied. In addition, the experiments showed that the SID of AA is different according to the feedstuffs.

On average, SPC showed the highest SID of all the feed stuffs tested in this study, which makes it an excellent protein source for birds in the pre-starter phase. The high digestibility of AA in pre-starter diets is important, since it has been related that dietary AA affects the body weight gain, the growth rate, the feed conversion ratio, the internal organ development of broilers [12] and the improved function of the gastrointestinal tract of broilers [13]. Some factors influence the AA digestibility in broilers. [17] verified that the defatting process of insect meal increased glutamic acid, proline, and serine digestibility. Yaghobfar [1] verified that the AA digestibility of soybean, sunflower and canola meals was lower in broilers than in intact and caecectomized cockerels, indicating that age affects the use of AA by broilers.

The SID of lysine, methionine, histidine, alanine, and as partate were similar between the CPS and the DPB, indicating that DPB is a great alternative animal byproduct to use in pre-starter broilers’ diets. Furthermore, the SID of isoleucine of DBP increased with EC inclusion. Lysine, methionine, and threonine are the first three limiting AA for broilers fed a corn-soybean meal diet and are present in great quantities in SPC and DPB. Therefore, [18] related that the spray-dried plasma improves early intestinal health and supports an efficient immune system response both locally at the intestine and systemically, thereby benefiting growth, feed efficiency, and survival of broilers.

The CGM presented the lowest SID of indispensable AA in pre-stater diets. However, the addition of EC was able to increase the SID of arginine and glutamic acid in the broilers fed the diet containing CGM. The CGM showed the lowest digestibility coefficients among the plant-based products, which may be due to its high fibre content, which reduces the AA digestibility.

At the pre-starter phase, the SID of arginine, branched chain-aminoacids, glycine, serine, aspartate, and glutamic acid increased in EC-supplemented diets. These AA are classified as polar and non-polar, indicating that the EC did not improve the digestibility of a specific group of AAs. The SID of these AA was increased up to 2.41% in mean, with the EC inclusion. The results agree with [6], verifying that the exogenous protease addition resulted in an increase in ileal AA digestibility of over 2.5%. There are many mechanisms by which the enzyme improves the SID of AA. The EC reduces the viscosity of digesta [1921], increases digesta retention time in the ileum [22], facilitating the digestion of nutrients by the digestive enzymes. Furthermore, it has been shown that the phytase plus xylanase combination increased sodium digestibility [22]. Since AA absorption is sodium-dependent, the increase of sodium digestibility could result in an enhanced SID of AA. In addition to these factors, the addition of exogenous protease to the diet increases the jejunal expression of genes responsible for peptide transport [6], resulting in better utilization of some AA. Cowieson et al [23] reported that exogenous protease may influence digestive dynamics through altered secretion of intestinal mucin, improved tight junction integrity and changed emphasis on AA transport.

The SID of AA within each feedstuff with or without EC was studied in the pre-starter phase. In the SPC, the SID were significantly higher for valine and cystine in the EC-supplemented diets. It was verified that all the AA present SID up to 90% in SPC. The inherent high digestibility of AA of SPC could contribute to a lack of effect of EC in enhancing the SID of other AA.

The SID of leucine, glycine and aspartate on POM was improved when the EC was used. The improvement of glycine digestibility in the pre-starter diet is important. Dietary glycine may need to be considered as a limiting nutrient in early nutrition, especially if the CP is low, and only vegetable ingredients are being used [24].

At the starter phase, it was verified that the SID of some AA of SPC, DBP, and CGM was similar, indicating better utilization of AAs of alternative feedstuffs with the increase of age. In this context, it is important to evaluate differences in AA digestibility in broiler chicks in the first week of life, given the limitations that occur in the digestive processes that affect nutritional utilization at that stage [25,26]. Because AA digestibility in birds is determined in the third week of life, differences in physiological maturity, especially in terms of intestinal functions and enzyme action, are greater than in the pre-starter phase, which can affect nutrient utilization efficiency and body development in these animals.

At the starter phase, only the SID of isoleucine, phenyl alanine and glycine increased with EC addition in the diet (average of increase of 2.33%). At the starter phase, the digestive system of the broiler is completely developed, and age could influence the SID of AA. Szczurek et al [27] verified that the SID value of AA in wheat was not influenced by the age of broilers, but the SID of most AA in triticale, and all the AA in barley, were higher in 28-day-old chickens compared with 14-day-olds. The results suggested that the SID coefficients of AA are influenced by the age of birds in a feedstuff-dependent way. In addition to the age of birds, other factors can affect the efficacy of exogenous enzymes and the AA digestibility. The dietary levels of available phosphorus and calcium can influence the efficacy of the combination of a multi-carbohydrase and phytase complex, on the digestibility of AAs of broilers [28].

The standardized AA contents of the feedstuffs were cal culated from the total AA content and the SID. Although the feedstuffs studied are protein sources, the contents of AA in each presented great variation. The digestible AA content of SPC was, on average, lower than those observed by [29], probably due to the lower protein levels found in this feedstuff in the present experiment. In fact, differences in nutritive value do exist between SBM from different origins in terms of nutrient contents, apparent metabolizable energy, and digestible AA [2].

The POM showed the greatest variation in digestible AA content between the feedstuffs of animal origin. This result can be attributed to the broad variations in its composition, which also explains the divergent AA compositions between different studies. The observed differences in AA content can be attributed to a lack of standardization in the processing of the evaluated feedstuffs. The processing of a feedstuff greatly influences the digestibility of AA. Overprocessing, for instance, can lead to a deficiency in sulfur-containing AAs, especially cystine, which is converted to lanthionine, which in turn has low nutritional value. On the other hand, insufficient processing may result in incomplete hydrolysis, which translates into lower nutrient digestibility [30]. The reduced digestibility of lysine may be attributed to the formation of Maillard reaction products during thermal processing.

In summary, we verified that the EC effectively improved the SID of AA of feedstuffs, resulting in the better utilization of some AA by birds. The addition of EC increased AA digestibility by an average of 2.41% and 2.33%, respectively, at the pre-starter and starter phases.

CONCLUSION

The addition of an EC to broiler pre-starter and starter diets is efficient in increasing the SID of AA on SPC, POM and DBP.

Notes

CONFLICT OF INTEREST

We certify that there is no conflict of interest with any financial organization regarding the material discussed in the manuscript.

FUNDING

The authors would like to thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the research funding (Process number 156224/2010-0), the São Salvador Alimentos, the Evonik and the Cargill.

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Figure 1

2D plot generated by principal component analysis. The graph shows a separation between the feedstuffs with or without the enzyme complex and their relationship to the standardized ileal digestibility (SID) of amino acids (AA), based on multivariate analysis in pre-starter phase. CGM, corn gluten meal; CGM_EC, corn gluten meal with enzyme complex; SPC, soy protein concentrate; SPC_EC, soy protein concentrate with enzyme complex; POM, poultry offal meal; POM_EC, poultry offal meal with enzyme complex; DBP, dried bovine plasma; DBP_EC, dried bovine plasma with enzyme complex.

Figure 2

2D plot generated by principal component analysis. The graph shows a separation between the feedstuffs with or without the enzyme complex and their relationship to standardized ileal digestibility (SID) of amino acids (AA), based on multivariate analysis in starter phase. CGM, corn gluten meal; CGM_EC, corn gluten meal with enzyme complex; SPC, soy protein concentrate; SPC_EC, soy protein concentrate with enzyme complex; POM, poultry offal meal; POM_EC, poultry offal meal with enzyme complex; DBP, dried bovine plasma; DBP_EC, dried bovine plasma with enzyme complex.

Table 1

Ingredient composition of the experimental diets fed to broilers, as fed-basis (%) (Experiment I and II)

Ingredient PFD CGM CGM+EC SPC SPC+EC POM POM+EC DBP DBP+EC
Starch 81.0 61.0 60.95 61.0 60.95 64.0 63.95 64.0 63.95
Corn gluten meal, 60% - 20.0 20.00 - - - - - -
Soy protein concentrate - - - 20.0 20.0 - - - -
Offal meal - - - - - 17.0 17.0 - -
Dried bovine plasma - - - - - - - 17.0 17.0
Soybean oil 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00 4.00
Dicalcium phosphate 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65 2.65
Limestone 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.70 0.70
Common salt 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60
Sugar 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00
Vitamin-mineral supplement1) 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.04
Enzyme complex2) - - 0.05 - 0.05 - 0.05 - 0.05
Antioxidant3) 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01
Inert4) 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00
Marker5) 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00
Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0

PFD, diet protein free; CGM, corn gluten meal; EC, enzyme complex; SPC, soy protein concentrate; POM, poultry offal meal; DBP, dried bovine plasma.

1)

Provides per kilogram of product: folic acid 200 mg, pantothenic acid 3,120 mg, biotin 10 mg, copper 1,997 mg, choline 78.10 g, enramycin 2,000 mg, iron 11.25 g, iodine 187.47 mg, maduramicin 937.50 mg, manganese 18.74 g, niacin 8,400 mg, nicarbazin 10 g, selenium 75 mg, vitamin A 1,680,000 IU, vitamin B1 436.50 mg, vitamin B12 2,400 mcg, vitamin B2 1,200 mg, vitamin B6 624 mg, vitamin D3 400,000 IU, vitamin E 3,500 IU, vitamin K3 360 mg, zinc 17.50 g.

2)

Axtra®.

3)

BHT (butylated hydroxytoluene).

4)

Rice husk.

5)

Celite (ash insoluble in acid).

Table 2

Dry matter, crude protein contents and total amino acid composition of different feedstuffs for broiler, expressed in percentage (as-fed basis)1)

Items CGM SPC POM DBP
Dry matter 91.62 94.03 95.01 92.08
Crude protein 62.09 62.36 63.73 70.30
Indispensable AA
 Lysine 1.01 3.81 4.14 6.86
 Methionine 1.47 0.84 1.39 0.81
 Methionine+cystine 2.58 1.73 2.05 3.68
 Threonine 2.07 2.52 2.51 4.95
 Arginine 1.97 4.55 4.16 4.01
 Histidine 1.33 1.60 1.06 2.88
 Valine 2.83 2.80 2.93 4.96
 Isoleucine 2.51 2.74 2.42 2.35
 Leucine 10.23 4.85 4.48 7.21
 Phenylalanine 3.90 3.20 2.51 4.41
 Glycine 1.49 2.64 4.74 2.98
Dispensable AA
 Cystine 1.10 0.89 0.67 2.17
 Alanine 5.51 2.72 3.34 4.02
 Aspartic acid 3.77 7.25 4.49 8.12
 Glutamic acid 13.59 11.28 7.02 11.79
 Serine 3.12 3.34 4.60 4.98
 Proline 1.56 3.04 4.65 4.11
1)

Aminogram developed by Evonik Industries AG Feed Additives/Animal Nutrition Services.

CGM, corn gluten meal; SPC, soy protein concentrate; POM, poultry offal meal; DBP, dried bovine plasma; AA, amino acid.

Table 3

Standardized ileal digestibility of amino acids (%) of feedstuffs determined in seven-day-old broilers

Items Lys Met Cys M+C Thr Arg His Val Iso Leu Phe Gly Ser Pro Ala Asp Glu
Feedstuffs (F)
 CGM (60%) 81.62b 78.06c 79.60b 77.74c 77.79d 82.04c 73.44c 78.96c 79.38b 75.95d 74.16c 76.44c 74.48d 73.00c 73.66c 74.46b 73.03d
 SPC 95.04a 97.57a 91.87a 97.35a 96.88a 98.33a 96.11a 93.98a 94.41a 95.11a 98.27a 93.36a 98.47a 97.73a 93.47a 91.67a 96.84a
 POM 85.26b 84.86b 78.90b 80.33c 84.47c 87.01b 83.71b 78.96c 79.71b 84.08c 83.58b 74.04d 78.42c 74.53c 82.01b 62.82c 82.51c
 DBP 94.63a 96.91a 78.77b 86.73b 88.73b 87.56b 94.54a 88.35b 83.98b 91.18b 95.87a 90.42b 91.92b 90.85b 95.37a 92.40a 93.21b
 SEM 1.50 0.92 1.78 1.12 1.00 0.64 1.24 0.68 1.63 0.60 1.10 0.71 0.76 1.20 1.11 0.54 0.74
Enzyme complex (EC)
 − 87.94 88.57 80.56 85.01 86.17 87.83b 85.83 84.24b 82.60 85.59b 86.82 82.65b 84.89b 82.70 85.09 79.13b 85.08b
 + 90.33 90.13 84.01 86.06 87.77 89.64a 88.07 85.88a 86.14 87.57a 89.12 84.47a 86.75a 85.36 87.17 81.55a 87.72a
 SEM 1.06 0.65 1.25 0.79 0.71 0.45 0.87 0.48 1.15 0.84 0.77 0.50 0.54 0.84 0.78 0.38 0.52
p-value
 F <0.001 <0.001 0.002 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
 EC 0.1502 0.1331 0.0888 0.381 0.15 0.0223 0.1082 0.044 0.0624 0.0109 0.0709 0.0337 0.0415 0.0581 0.0971 0.0022 0.0078
 F×EC 0.5725 0.9601 0.2853 0.9226 0.7057 0.4947 0.9824 0.4705 0.2612 0.585 0.7477 0.5042 0.5221 0.8378 0.7576 0.0067 0.3278

M+C, methionine+cystine; CGM, corn gluten meal; SPC, soy protein concentrate; POM, poultry offal meal; DBP, dried bovine plasma; SEM, standard error of the means; (−) without EC; (+) with EC.

a–d

Means within a column-subgroup with no common superscript letters are significantly different at p<0.05 by Scott Knott test.

Table 4

Standardized ileal digestibility of amino acids (%) of feedstuffs with or without enzyme complex in seven-day-old broilers

Items Corn gluten meal (60%) Soy protein concentrate Poultry offal meal Dried bovine plasma




+ SEM p-value + SEM p-value + SEM p-value + SEM p-value
Indispensable AA
 Lys 78.64 84.59 2.12 0.082 94.62 95.47 2.12 0.782 84.06 86.46 2.12 0.447 94.45 94.80 2.12 0.91
 Met 77.00 79.12 1.31 0.285 96.70 98.45 1.31 0.374 84.07 85.65 1.31 0.419 96.53 97.29 1.31 0.693
 M+C 77.73 77.76 1.59 0.989 96.57 98.13 1.59 0.508 80.03 80.63 1.59 0.796 85.73 87.72 1.59 0.403
 Thr 77.71 77.78 1.42 0.934 95.60 98.16 1.42 0.239 82.97 85.98 1.42 0.172 88.40 89.07 1.42 0.748
 Arg 80.30b 83.79a 0.90 0.026 97.94 98.73 0.90 0.552 86.10 87.93 0.90 0.191 87.00 88.13 0.90 0.402
 His 72.51 74.37 1.75 0.476 94.67 97.56 1.75 0.277 82.44 84.89 1.75 0.334 93.71 95.38 1.75 0.518
 Val 78.16 79.76 0.96 0.276 92.34b 95.62a 0.96 0.043 78.16 79.77 0.96 0.273 88.32 88.37 0.96 0.971
 Iso 78.65 80.10 2.31 0.669 93.92 94.90 2.31 0.772 78.72 80.71 2.31 0.559 79.10b 88.86a 2.31 0.017
 Leu 75.31 76.59 0.84 0.317 94.27 95.96 0.84 0.198 82.36b 85.81a 0.84 0.0207 90.43 91.93 0.84 0.246
 Phe 72.44 75.89 1.55 0.156 97.14 99.39 1.55 0.337 82.00 85.17 1.55 0.1882 95.72 96.03 1.55 0.891
 Gly 75.28 77.60 1.00 0.142 93.07 93.66 1.00 0.689 72.32b 75.76a 1.00 0.042 89.95 90.89 1.00 0.529
Dispensable AA
 Cys 80.47 78.74 2.52 0.641 87.38b 96.35a 2.52 0.035 77.22 80.57 2.52 0.3744 77.17 80.37 2.52 0.395
 Ala 71.97 75.36 1.57 0.166 92.08 94.87 1.57 0.245 81.00 83.03 1.57 0.3888 95.30 95.45 1.57 0.946
 Asp 74.12 74.81 0.77 0.547 91.45 91.89 0.77 0.700 59.22b 66.43a 0.77 <0.001 91.74 93.08 0.77 0.255
 Glu 70.56b 75.51a 1.05 0.010 96.05 97.63 1.05 0.322 81.03 84.00 1.05 0.0831 92.69 93.75 1.05 0.497
 Ser 73.24 75.72 1.08 0.143 98.31 98.63 1.08 0.842 76.71 80.14 1.08 0.055 91.32 92.51 1.08 0.459
 Pro 71.45 74.56 1.69 0.231 97.34 98.12 1.69 0.753 72.72 76.35 1.69 0.1697 89.30 92.40 1.69 0.232

SEM, standard error of the means; AA, amino acids; M+C, methionine+cystine.

a,b

Means within a feedstuff group with no common superscript letters are significantly different at p<0.05 by Scott Knott test.

Table 5

Standardized ileal digestibility of amino acids (%) of feedstuffs determined in 21-day-old broilers

Items Lys Met Cys M+C Thr Arg His Val Iso Leu Phe Gly Ser Pro Ala Asp Glu
Feedstuffs (F)
CGM (60%) 91.51c 94.60b 86.71 92.77a 93.60a 94.75b 89.21b 94.51a 93.80a 95.80a 83.74 b 88.51b 95.14a 92.57a 94.86a 89.88b 94.43a
 SPC 94.29b 98.28a 91.40 95.11a 94.71a 97.11a 94.06a 93.92a 93.62a 93.24b 98.42 a 91.31a 96.17a 95.61a 91.88b 88.81b 95.11a
 POM 81.48d 82.56c 89.41 83.27b 82.03b 84.12c 80.57c 80.43b 79.77b 81.74c 83.73 b 77.93c 82.56b 75.33b 80.76c 64.81c 79.21b
 DBP 97.88a 98.38a 92.91 95.89a 96.54a 93.70b 96.07a 92.39a 80.53b 96.89a 97.61 a 93.01a 94.40a 94.67a 96.01a 94.44a 94.83a
 SEM 0.41 0.47 2.34 1.20 1.88 0.56 0.99 1.09 0.71 0.66 0.88 0.59 1.01 1.00 0.67 0.42 0.80
Enzyme complex (EC)
 − 91.09 93.00 88.13 91.26 91.65 92.08 89.49 89.79 86.05b 91.36 89.45b 86.91b 91.17 88.58 90.18 84.27 90.49
 + 91.48 93.91 92.08 92.26 91.80 92.76 90.46 90.83 87.80a 92.47 92.30a 88.46a 92.97 90.51 91.57 84.70 91.30
 SEM 0.29 0.33 1.65 0.85 1.33 0.39 0.70 0.77 0.50 0.46 0.62 0.42 0.71 0.70 0.47 0.29 0.57
p-value
 F <0.001 <0.001 0.3366 <0.001 0.0024 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001 <0.001
 EC 0.3668 0.092 0.1301 0.432 0.9386 0.2617 0.3573 0.3713 0.04 0.134 0.0121 0.0311 0.112 0.0903 0.0733 0.3455 0.3473
 F×EC 0.5727 0.6154 0.7188 0.9688 0.9984 0.5755 0.8045 0.8951 0.1352 0.6389 0.0743 0.9904 0.5991 0.7419 0.9579 0.1436 0.5604

M+C, methionine+cystine;CGM, corn gluten meal; SPC, soy protein concentrate; POM, poultry offal meal; DBP, dried bovine plasma; SEM, standard error of the means; (−) without EC; (+) with EC.

a–d

Means within a column-subgroup with no common superscript letters are significantly different at p<0.05 by Scott Knott test.

Table 6

Standardized ileal digestibility of amino acids (%) of feedstuffs with or without enzyme complex in 21-day-old broilers

Items Corn gluten meal (60%) Soy protein concentrate Poultry offal meal Dried bovine plasma




+ SEM p-value + SEM p-value + SEM p-value + SEM p-value
Indispensable AA
 Lys 91.20 91.82 0.58 0.471 94.11 94.48 0.58 0.664 80.93 82.04 0.58 0.211 98.16 97.62 0.58 0.532
 Met 93.68 95.53 0.67 0.087 97.95 98.62 0.67 0.501 82.03 83.10 0.67 0.293 98.36 98.41 0.67 0.959
 M+C 91.81 93.73 1.70 0.484 94.61 95.62 1.70 0.686 82.89 83.66 1.70 0.757 95.75 96.04 1.70 0.907
 Thr 93.24 93.97 2.66 0.851 94.76 94.66 2.66 0.979 82.06 82.02 2.66 0.990 96.54 96.56 2.66 0.996
 Arg 94.27 95.24 0.79 0.411 97.19 97.04 0.79 0.893 83.19 85.06 0.79 0.132 93.70 93.72 0.79 0.989
 His 87.96 90.47 1.40 0.243 94.10 94.03 1.40 0.974 80.00 81.16 1.40 0.577 95.93 96.23 1.40 0.885
 Val 93.32 95.72 1.54 0.304 93.50 94.35 1.54 0.707 80.04 80.83 1.54 0.725 92.35 92.44 1.54 0.966
 Iso 92.21 95.39 1.01 0.057 94.13 93.12 1.01 0.503 79.33 80.21 1.01 0.556 78.55b 82.52a 1.01 0.024
 Leu 94.86 96.75 0.93 0.192 92.68 93.81 0.93 0.419 80.87 82.62 0.93 0.224 97.07 96.73 0.93 0.804
 Phe 80.90b 86.57a 1.25 0.012 98.33 98.53 1.25 0.914 80.90b 86.57a 1.25 0.012 97.48 97.75 1.25 0.882
 Gly 87.83 89.19 0.84 0.286 90.55 92.07 0.84 0.237 77.00 78.87 0.84 0.154 92.28 93.74 0.84 0.255
Dispensable AA
 Cys 82.64 90.80 3.31 0.119 90.75 92.06 3.31 0.786 87.11 91.73 3.31 0.352 92.06 93.77 3.31 0.724
 Ala 94.20 95.53 0.95 0.351 91.29 92.48 0.95 0.403 79.77 81.77 0.95 0.176 95.50 96.53 0.95 0.465
 Asp 89.11 90.66 0.59 0.104 89.48 88.15 0.59 0.154 64.72 64.91 0.59 0.827 93.80 95.09 0.59 0.167
 Glu 93.67 95.20 1.14 0.370 95.53 94.71 1.14 0.622 78.07 80.36 1.14 0.193 94.73 94.95 1.14 0.892
 Ser 94.92 95.38 1.43 0.825 96.00 96.35 1.43 0.866 80.79 84.35 1.43 0.116 92.98 95.84 1.43 0.195
 Pro 91.79 93.36 1.41 0.457 95.45 95.77 1.41 0.877 73.65 77.03 1.41 0.130 93.45 95.91 1.41 0.254

SEM, standard error of the means; AA, amino acids; M+C, methionine+cystine.

a,b

Means within a feedstuff group with no common superscript letters are significantly different at p<0.05 by Scott Knott test.

Table 7

Standardized digestible amino acid contents of feedstuffs (%) (as-fed basis)1)

Items CGM SPC POM DBP
Dry matter 91.62 94.03 95.01 92.08
Crude protein 62.09 62.36 63.73 70.30
Lysine 0.92 3.43 3.31 5.95
Methionine 1.35 0.77 1.15 0.66
Methionine+cystine 2.33 1.49 1.54 3.26
Threonine 1.94 2.36 1.93 4.28
Arginine 1.79 4.24 3.83 3.33
Histidine 1.21 1.47 0.93 2.35
Valine 2.57 2.46 2.32 4.40
Isoleucine 2.26 2.44 1.94 1.99
Leucine 9.31 4.31 3.63 6.20
Phenylalanine 3.51 2.85 2.11 3.71
Cystine 1.02 0.79 0.46 1.77
1)

Aminogram developed by Evonik Industries AG Feed Additives/Animal Nutrition Services.

CGM, corn gluten meal; SPC, soy protein concentrate; POM, poultry offal meal; DBP, dried bovine plasma;