Evaluation of standardized ileal digestibility of amino acids in fermented soybean meal for nursery pigs using direct and difference procedures

Article information

Anim Biosci. 2023;36(2):275-283
Publication date (electronic) : 2022 September 2
doi : https://doi.org/10.5713/ab.22.0269
1Department of Animal Science, North Carolina State University, Raleigh, NC, 27695, USA
*Corresponding Author: Sung Woo Kim, E-mail: sungwoo_kim@ncsu.edu
Received 2022 July 11; Revised 2022 July 25; Accepted 2022 August 5.

Abstract

Objective

This study was to evaluate standardized ileal digestibility (SID) of amino acids (AA) in fermented soybean meal (FSBM) for nursery pigs using both direct procedure and difference procedure when FSBM was added at 20% in diets.

Methods

Forty-eight pigs at 9.2±0.9 kg body weight (BW) were individually housed and allotted to 4 treatments. Treatments included NFD (a semi-purified N free diet), FSD (a diet with 20% FSBM), CBD (corn basal diet), and CFD (corn basal diet:FSBM at 80:20). The FSD was used to measure AA digestibility in FSBM using the direct procedure, whereas CBD and CFD were used in the difference procedure. Pigs were fed for 10 days (0.09×BW0.75 kg per day) and euthanized to collect ileal digesta for TiO2 and AA.

Results

Total endogenous AA loss was 12.1 g/kg of dry matter intake. The apparent ileal digestibility (AID) Thr was greater (p<0.05) and AID His (p = 0.073) and Leu (p = 0.052) tended to be greater using the direct procedure compared with the difference procedure. The SID Thr were greater (p<0.05) in FSBM for nursery pigs calculated using a direct procedure compared with a difference procedure. In addition, SID Lys in FSBM was about 83% to 88% for nursery pigs higher than SID Lys described in National Research Council (2012).

Conclusion

The SID of AA in FSBM when included at practical levels using the direct procedure were similar to those from the difference procedure. Considering the SID of AA obtained using both direct and difference procedures, FSBM is an effective protein supplement providing highly digestible AA to nursery pigs. The SID of AA from this study was considerably higher than those previous reported. This study also indicates the importance of including the test feedstuffs at practical levels when evaluating digestibility.

INTRODUCTION

Soybean meal has various anti-nutritional factors including trypsin inhibitors, lectins, glycinin, and β-conglycinin possibly causing negative impacts on growth and nutrient digestion of pigs [13]. Various processing for soybean meal has been developed to eliminate or reduce the anti-nutritional factors in soybean meal. Fermented soybean meal (FSBM) provides plant-based protein after microbial fermentation to reduce the anti-nutritional factors. Fermented soybean meal contained the lower concentrations of glycinin, β-glycinin, and trypsin inhibitors compared conventional soybean meal [2,3]. Previous studies has also been shown that FSBM positively affects not only growth performance and protein digestibility [35], but also inflammatory response and antioxidant activity of nursery pigs compared with conventional soybean meal [6].

Availability of amino acids (AA) in FSBM has been re ported in previous literature. Interestingly, there is substantial difference on the standardized ileal digestibility (SID) AA (SID Lys; 75% vs 86%) in FSBM for growing pigs between NRC [7] and the latest report [8]. Standardized ileal digestibility of AA in FSBM reported in NRC [7] is based on two observations and the digestibility did not consider the growth stages of pigs. Other published studies reporting SID AA in FSBM for nursery pigs used a direct procedure with at least 30% FSBM [4,5,912]. The direct procedure uses a diet mainly with a test feedstuff and other minor feedstuffs that are fully digestible nutrients so that the digestibility of interested nutrients are mainly contributed from the test feedstuff. In direct procedure, the use of a test feedstuff is often greater than practical inclusion levels included in the diet [4,5,10]. Considering that practical inclusion levels of FSBM in nursery feeds are between 3% to 20% [3,9,12], SID AA measured in a diet containing 30% FSBM could underestimate its digestibility due to palatability or antinutritional factors at increased levels [13,14]. The difference procedure can be applied to estimate digestibility of a test feedstuff at practical inclusion levels as other typical feedstuffs can be used in a test diet [14]. In the difference procedure, a test feedstuff replaces a basal diet at one or several designated proportions and then the digestibility of nutrients in the test feedstuff is calculated considering the contribution of digestibility from a basal diet [1315]. A basal diet is composed of only a few feedstuffs that are well characterized for their digestibility. According to Adeola [16], the procedure error would be related to the replacement levels of a test feedstuff in test diets because the nutrient digestibility in a feedstuff is estimated based on extrapolation to 100% replacement of interested nutrient against the replacement levels. Thus, the AA digestibility in FSBM for nursery pigs should be estimated with consideration the practical inclusion levels in test diets for both the direct procedure and the difference procedure. It is, therefore, hypothesized that SID AA in FSBM for nursery pigs should be evaluated through both direct procedure and difference procedure with consideration of a practical inclusion level of FSBM in swine diets. Therefore, the objective of this study was to evaluate SID of AA in FSBM for nursery pigs by using both direct procedure and difference procedure when FSBM is added at 20% in testing diets fed to nursery pigs.

MATERIALS AND METHODS

Animal care

The experimental protocol was approved by the Institutional Animal Care and Use Committee of North Carolina State University.

Animals, experimental design, and diets

A total of 48 newly weaned pigs (24 barrows and 24 gilts) at 21 d of age fed a common diet (26% crude protein [CP] and 15.2% lactose) for 7 days. Nursery pigs at 9.24±0.90 kg body weight (BW) were allotted to 4 treatments with 12 replications per diet in a randomized complete block design with sex and initial BW as blocks. Treatments were NFD (a semi-purified N free diet to measure basal endogenous AA losses), FSD (a diet with 20% FSBM [Pepsoygen; Nutraferma Inc., North Sioux City, SD, USA]), CBD (a corn basal diet), and CFD (a corn basal diet:FSBM = 80:20). Four experimental diets were formulated (Tables 1, 2). Two diets contained corn or FSBM (Pepsoygen; Nutraferma Inc., USA), respectively, as the source of AA and another diet was formulated by adding a certain amount of FSBM into the CBD diet for a mixture of corn and FSBM diet that containing 80% of CBD and 20% FSBM as described by Adeola [16]. A NFD based on corn starch and sucrose was also prepared to measure the endogenous losses of AA. Experimental diets were supplemented with 0.4% titanium dioxide (TiO2) as an indigestible marker. Vitamins and minerals were included in the diets to meet or exceed requirement estimates [7]. Pigs were individually housed in each pen that were equipped with a feeder and a nipple drinker.

Composition of experimental diets1) (as-fed basis)

Analyzed composition of experimental diets1) (as-fed basis)

Feeding and sample collection

Pigs were fed the experimental diets for 10 d. During the following period, the daily feed allowance was approximately 0.09×BW0.75 kg was provided to the animals as 2 equal meals at 08:00 and 17:00. Pigs had free access to water. After 10 d feeding, all pigs were euthanized at the end of the experiments to collect at least 30 mL ileal digesta samples. Ileal digesta were stored at −20°C immediately after ileal digesta collection.

Chemical analysis

The frozen ileal digesta samples were dried in a freeze dryer. Ingredient and diet samples were analyzed for dry matter (DM; method 930.15) and CP (method 990.03). Diet samples were also analyzed for calcium (method 978.02), phosphorus (method 946.06), neutral detergent fiber (method 2002.04), and acid detergent fiber (method 973.18) as described in AOAC [17]. Amino acid concentrations of diets and ileal digesta samples were determined by ion-exchange chromatography with post-column derivatization with ninhydrin. Before analysis, samples were liberated from the proteiADFn by hydrolysis with 6 N HCl for 24 h at 110°C (method 982.30). Methionine and cystine were analyzed as methionine sulfone and cysteic acid after cold performic acid oxidation overnight before hydrolysis. Tryptophan was determined after NaOH hydrolysis for 22 h at 110°C. The concentrations of titanium dioxide in diets and ileal digesta samples were determined by the procedures as previously described by Myers et al [18].

Calculation and statistical analysis

The apparent ileal digestibility and the true ileal digestibility of AA were calculated for all diets except the NFD, and endogenous losses of AA were calculated from pigs fed NFD as follows Kong and Adeola [13].

Apparent ileal digestibility (AID)=1-(AAi/AAd)×(Tid/Tii)Basal endogenous losses (BEL)(g/kg DMI)=AAi×(Tid/Tii)SID=[AID+(BEL/AAd)]

where Tid and Tii represent the concentration of Ti (g/kg DM) in diets and ileal digesta, respectively. The concentrations of AA (g/kg DM) in diets and ileal digesta represent AAd and AAi, respectively. The ileal digestibility of AA in FSBM from the diets that contained both corn and FSBM were also calculated by difference procedure [13].

AIDFSBM(%)=[(AIDMixed×AAMixed)-(AIDCorn×AACorn)]/AAFSBMSIDFSBM(%)=[(SIDMixed×AAMixed)-(SIDCorn×AACorn)]/AAFSBM

where AAcorn and AAMixed represent the concentration of AA (g/kg DM) in corn and corn and FSBM mixed diets, respectively. AIDcorn or SIDcorn and AIDMixed or SIDMixed are measured AID or SID of AA in corn and corn and FSBM mixed diets, respectively.

Data were analyzed using the Proc Mixed procedure of SAS (SAS Inst. Inc., Cary, NC, USA). In the statistical model, diet included as a fixed variable and a block and sex were the random variables for ileal digestibility in respective diets. Least squares of means for each treatment were calculated. For the comparison between measured and predicted AID and SID of AA in FSBM, the predicted digestibility was subtracted from the measured digestibility and the difference between measured and predicted values in FSBM were tested using a t-test. The statistical difference was considered significant with p<0.05, whereas 0.05≤p<0.10 was considered as tendency.

RESULTS

Amino acid composition in corn and FSBM used in this study is described in Table 3. The Lys, Thr, Trp, and Met were 0.26%, 0.27%, 0.06%, and 0.17% in corn and 3.16%, 2.11%, 0.61%, and 0.75% in FSBM, respectively. During the experiment, one pig fed diet based on NFD and two pigs fed diet based on FSBM were removed from the 9 experiment due to unnormal healthy conditions. The AID of AA in pigs fed FSD were higher (p<0.05) compared with the pigs fed CBD (Table 4). Endogenous AA losses were determine using pigs fed the NFD and average total 12.1 g/kg of dry matter intake (DMI) (Table 5). The SID of most AA in pigs fed FSD were higher (p<0.05) in the pigs compared with pigs fed CBD and CFD (Table 6).

Analyzed composition of test ingredients (as-fed basis)

Apparent ileal digestibility of amino acids in experimental diets

Basal endogenous losses of amino acids of nursery pigs fed an N-free diet

Standardized ileal digestibility of amino acids in experimental diets

There was no difference on the AID of Arg, Ile, Lys, Met, Phe, Trp, and Val in indispensable AA and Asp, Gly, Pro, Ser, and Tyr in dispensable AA of FSBM between direct and difference procedures (Table 7). The AID of Thr was greater (p<0.05) and AID of His (p = 0.073) and Leu (p = 0.052) tended to be greater if calculated using the direct procedure rather than difference procedure. The AID of Ala, Cys, and Ser were greater and the AID of Glu tended to be greater (p = 0.061) if calculated using the direct procedure rather than difference procedure.

Apparent ileal digestibility of amino acids in fermented soybean meal calculated using direct and difference procedures

There was no difference on the SID of most indispensable AA except for Thr (p<0.05) of FSBM between direct and difference procedures (Table 8). The SID of dispensable AA including Ala and Ser in FSBM were greater (p<0.05) and SID of dispensable AA including Cys (p = 0.054) and Gly (p = 0.079) in FSBM tended to be greater if calculated using the direct procedure rather than difference procedure.

Standardized ileal digestibility of amino acids in fermented soybean meal calculated using direct and difference procedures

DISCUSSION

Amino acids are responsible for the most parts of physiological responses for growth and maintenance in the body such as nutrient metabolism, immunity, and protein deposition [19,20]. In particular, nursery pigs would be susceptible from multiple stressors during postweaning periods, leading to reduced feed intake and growth retardation with impaired intestinal functions, especially barrier function and nutrient utilization [21,22]. According to previous studies, AA balance and some specific AA could be significantly engaged in the modulation of immunity and recovery the intestinal damage induced from weaning in nursery pigs [2325]. Thus, estimation of specific AA availability in feedstuff would be important to efficiently supply and utilize the AA for growth and health of nursery pigs.

Soybean meal is the main protein supplement in swine feeds, but it has been used at less than 20% in nursery feeds because the immature intestine of nursery pigs do not tolerate to digest the high levels of soybean meal [2,26,27]. Fermented soybean meal could be an effective source of soy protein and it is produced by mixing conventional soybean meal with water and a bacterial culture achieved from human food production, microbial fermentation, and then drying it on a plate or drum drier at a specific temperature to avoid heat damage to the protein [28]. Microbial fermentation by beneficial microbes such as Apergillus oryzae and Bacillus subtillits could effectively reduce anti-nutritional factors such as the trypsin inhibitor by 84%, glycinin by 40%, beta-conglycinin by 40%, and phytic acid by 35% with increasing protein content and producing smaller peptide size in conventional soybean meal [2,3,28]. Previous studies have shown that supplementation of FSBM positively affects growth performance and protein digestibility of nursery pigs compared with conventional soybean meal [35].

In this study, the analyzed compositions of indispensable and dispensable AA in FSBM were similar or slightly higher than those in conventional soybean meal described in NRC [7]. These difference would be possibly due to the inclusion rate of soybean hulls during the fermentation process, which may affect the AA concentrations in FSBM [29]. Microbial fermentation in soybean meal could decrease the composition of DM contents and trypsin inhibitors with increase in smaller peptide and fat contents and it would be accounted for by carbohydrate fermentation by Apergillus oryzae [2]. Thus, the use of fermented soybean would be beneficial to efficiently supply high AA through changing the AA profiles and reducing the antinutritional factors by microbial fermentation compared with conventional soybean meal.

In this study, the SID of AA in CBD and CFD diets for nursery pigs were relatively low compared with the SID of AA reported in previous studies. The CBD and CFD diets in this study were used to estimate the SID of AA in FSBM using a difference procedure. In contrast to the SID of AA in FSD, which was relatively similar to the SID of AA from previous literature [8,9,30], the possible reason for this observation would be related to the inclusion of corn as a major feedstuff in CBD and CFD diets. According to Oliveira et al [15], the SID of AA in the corn-basal diet and corn-SBM diet was over 85% for growing pigs. However, considering the growth phase of pigs, Trindade Neto et al [31] showed that the SID of AA in corn for nursery pigs was relatively low with the SID of most AA at below 30%. Sauer et al [32] also showed that the SID of AA in corn for nursery pigs was also relatively similar to the SID of AA in this study. It can be explained by the high variable digestibility of AA in corn [3335]. However, the possible reason for this observation could also be related to the capacity of nursery pigs to digest the plant feedstuff during the post-weaning period, although corn is one of the most used cereals as an energy source containing less antinutritional factors. According to Mahan [36], starch from cereal grains is low palatable and less digestible for newly weaned pigs rather than lactose, because their digestive tract would be adapted to lactose digestion by milk consumption during lactation. Moeser et al [37] showed that intestinal damage by weaning stress would be sustained for about 14 d after weaning with impaired intestinal functions, resulting in a reduction in the digestive and absorptive capacity in the small intestine of nursery pigs. Lindemann et al [38] also showed the activities of digestive enzymes in nursery pigs could be reduced during the first 2 wks after weaning. In this study, although the pigs had an adaptation period for 10 d after weaning, their intestine would be limited to digesting the corn as a plant feedstuff in CBD and CFD diets. Therefore, the results in this study indicate that the inclusion level of a test feedstuff that affects the inclusion of other typical feedstuffs such as corn in test diets for a difference procedure could be important to determine the SID of AA in feedstuff for nursery pigs.

Amino acid digestibility in feed ingredients have been de termined either by direct procedure or difference procedure [13,14]. The direct procedure can be used for determining digestibility of nutrients in the feed ingredients with high feeding value such like palatable feedstuff and low content of antinutrients [13,14]. In difference procedure, when the test feedstuff would not be solely used as the major ingredient due to poor palatability, high content of protein, or anti-nutritional factors. For a difference procedure, testing diets are required to be formulated with both the test feedstuff and cereal feedstuff. A direct procedure has been widely used to evaluate the SID of protein feedstuff rather than a difference procedure [4,5,8,9,15], because having poor palatability or high content of proteins and antinutritional factors can interrupt the evaluation of AA digestibility in a feedstuff using a difference procedure [13]. Based on the findings in previous studies [2,3,28], it could suggest that FSBM at a practical inclusion level can have additivity of SID AA because microbial fermentation leads to the change in protein profile and the reduction of the concentration of antinutritional compounds in conventional soybean meal. The inclusion level of soy protein source below 20% in early weaner diets also has been considered the palatability and digestive capacity of nursery pigs [2,26,27].

In this study, the AID of dispensable AA including His, Leu, and Thr in FSBM from direct procedure were less than from difference procedure, but the SID of AA in FSBM were not different except for Thr. The possible reason for the non-additivity on AID and SID of these AA would be related to the contribution of digestible AA in corn for a difference procedure. This study considered the practical inclusion level of FSBM in nursery feeds and thus the experiment diets contained the relatively lower inclusion levels of FSBM at 20% in the testing diets compared with previous studies using about 30% [4,5,810,12]. It could also bring an increase in the portion of the use of corn in the test diets for a difference procedure. This may indicate that digestibility of AA in corn could result in relatively high variation in AID and SID of AA in corn and thus it may affect the estimation for a difference procedure to measure AID and SID of several AA in FSBM for nursery pigs. Previous studies have shown the cereal grains including corn could have high variable digestibility of AA [3335] that were not also in accordance with NRC [7]. According to Stein et al [33], the AID of AA in feedstuff could not be additive depending on the AA composition in the testing diets. Stein et al [39] also showed that the low concentration of AA in feed ingredients may be potential to cause variation on the AID of AA due to the relatively greater contribution of AA of endogenous origin to the ileal output of AA in feed ingredients. Xue et al [40] also showed that the predicted AID of AA based on the values from mixed diets containing a high proportion of corn as low CP feedstuff be likely to be lower than the determined values by a direct method. Therefore, an increase in the portion of corn in the testing diets for a difference procedure may influence to be underestimated values for the AID and SID of several AA in FSBM using a difference procedure and thus resulted in the lack of additivity.

Most of the previous literature reported the SID of AA in FSBM for pigs by a direct procedure [4,5,8,9], but there is limited information about those from a difference procedure. Although this study shows the SID of AA in FSBM using both a direct procedure and a difference procedure, comparing the results with literature within the same method would be necessary. Comparing the SID of AA in previous reports with consideration of the type of FSBM, the BW of pigs, and the measuring procedure, interestingly, the SID of Lys in FSBM for pigs was lower than the values in conventional soybean meal. Cervantes-Pahm and Stein [4] also showed 9% lower SID Lys in FSBM with Aspergillus oryzae (77% vs 85%) than in conventional soybean meal for nursery barrows during 10.9 to 22.2 kg BW. The SID Lys in FSBM was 16% lower (75% vs 89%) than in conventional soybean meal in NRC [7]. The SID Lys in FSBM with Aspergillus oryzae and Bacillus subtilis was 2% lower (82% vs 84%) for nursery pigs at 10.4 kg initial BW in Rojas and Stein [5]. The SID Lys in FSBM with Streptococcus thermophiles and Saccharomyces cerevisiae was 5% (83% vs 88%) lower for growing barrows at 26.8 kg initial BW in Wang et al [9]. The SID Lys in FSBM with Aspergillus oryzae and Bacillus subtilis was 4% lower (86% vs 90%) for grower-finisher barrows at 30.4 kg initial BW in Yáñez et al [8]. Cervantes-Pahm and Stein [4] demonstrated that the reduced the SID of lysine would be results from the heating processing in FSBM production which is possibly causing the Maillard reaction with decreased the available Lys content. Besides, based on previous findings, the SID of AA in FSAM was not related to the BW of pigs or the procedure, because SID of AA in various types of FSBM would be influenced by the bacterial species as previously reported by Kim et al [11]. Indeed, the SID Lys in FSBMs seems to be getting increased as times go on. Based on the published years of studies, the initial studies showed underrated SID Lys for pigs compared with the latest studies. This study also shows that the SID Lys in FSBM was about 83 (difference procedure) to 88% (direct procedure) for nursery pigs. These values are relatively accordance in the values from the latest reports [8,9,30] rather than the initial reports [4,7,10]. It may be possibly due to the advances in the processing technology using microbial fermentation by specific bacteria to consider the impacts on available AA content in soybean meal for growing pigs [8,11,41]. Unfortunately, conventional soybean meal was not tested in this study indicating that it would not be available to directly comparison in the AA digestibility between FSBM and conventional soybean meal. Another possible reason could be suggested by the inclusion levels of FSBM in testing diets. Previous studies using a direct procedure with around 30% FSBM showed relatively low SID Lys (average 77%) in FSBM for nursery pigs [4,5,10]. In contrast, previous studies using a direct procedure with around 25% FSBM showed SID Lys at an average of 84% in FSBM for nursery pigs [9,12]. Due to possibly causing the low palatability or the content of antinutritional factors when a test feedstuff is added at high levels in test diets [13,14], the SID AA in FSBM would be variable by the inclusion level of FSBM in experimental diets.

CONCLUSION

In conclusion, the SID of AA in FSBM when included at practical levels using the direct procedure were relatively similar to those from the difference procedure. Considering SID of AA obtained using both direct procedure and difference procedure, FSBM is an effective protein supplement providing highly digestible AA to nursery pigs. The SID of AA from this study was considerably higher than those previous reported. This study also indicates the importance of including the test feedstuffs at practical levels when evaluating digestibility.

ACKNOWLEDGMENTS

The authors appreciate technical supports from Prof. Dong Yong Kil at Chung-Ang University (Anseong, Korea), Prof. Changsu Kong at Kyungpook National University (Sangju, Korea), Prof. Beob Gyun Kim at Konkuk University (Seoul, Korea), and Mr. Hyunjun Choi and Dr. Inkyung Park at North Carolina State University (Raleigh, NC, USA).

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

This study was financially supported from North Carolina Agricultural Foundation (#660101, Raleigh, NC, USA) and Nutraferma Inc. (North Sioux City, SD, USA).

References

1. Li DF, Nelssen JL, Reddy PG, et al. Transient hypersensitivity to soybean meal in the early-weaned pig. J Anim Sci 1990;68:1790–9. https://doi.org/10.2527/1990.6861790x .
2. Hong K-J, Lee C-H, Kim SW. Aspergillus oryzae GB-107 fermentation improves nutritional quality of food soybeans and feed soybean meals. J Med Food 2004;7:430–5. https://doi.org/10.1089/jmf.2004.7.430 .
3. Kim SW, van Heugten E, Ji F, Lee CH, Mateo RD. Fermented soybean meal as a vegetable protein source for nursery pigs: I. Effects on growth performance of nursery pigs. J Anim Sci 2010;88:214–24. https://doi.org/10.2527/jas.2009-1993 .
4. Cervantes-Pahm SK, Stein HH. Ileal digestibility of amino acids in conventional, fermented, and enzyme-treated soybean meal and in soy protein isolate, fish meal, and casein fed to weanling pigs. J Anim Sci 2010;88:2674–83. https://doi.org/10.2527/jas.2009-2677 .
5. Rojas OJ, Stein HH. Concentration of digestible, metabolizable, and net energy and digestibility of energy and nutrients in fermented soybean meal, conventional soybean meal, and fish meal fed to weanling pigs. J Anim Sci 2013;91:4397–405. https://doi.org/10.2527/jas.2013-6409 .
6. Roh S-G, Carroll JA, Kim SW. Effects of fermented soybean meal on innate immunity-related gene expressions in nursery pigs acutely challenged with lipopolysaccharides. Anim Sci J 2015;86:508–16. https://doi.org/10.1111/asj.12319 .
7. NRC. Nutrient requirements of swine: Eleventh Revised Edition Washington, DC, USA: The National Academies Press; 2012.
8. Yáñez JL, Woyengo TA, Jha R, Van Kempen TATG, Zijlstra RT. Nutrient digestibility of soybean products in grower-finisher pigs. J Anim Sci 2019;97:4598–607. https://doi.org/10.1093/jas/skz290 .
9. Wang Y, Lu WQ, Li DF, et al. Energy and ileal digestible amino acid concentrations for growing pigs and performance of weanling pigs fed fermented or conventional soybean meal. Asian-Australas J Anim Sci 2014;27:706–16. https://doi.org/10.5713/ajas.2013.13612 .
10. Urbaityte R, Mosenthin R, Eklund M, Piepho HP, Sauer N, Rademacher M. Standardised ileal crude protein and amino acid digestibilities in protein supplements for piglets. Arch Anim Nutr 2009;63:356–78. https://doi.org/10.1080/17450390903052631 .
11. Kim DH, Heo PS, Jang JC, Jin SS, Hong JS, Kim YY. Effect of different soybean meal type on ileal digestibility of amino acid in weaning pigs. J Anim Sci Technol 2015;57:11. https://doi.org/10.1186/s40781-015-0041-9 .
12. Sinn SM, Gibbons WR, Brown ML, Derouchey JM, Levesque CL. Evaluation of microbially enhanced soybean meal as an alternative to fishmeal in weaned pig diets. Animal 2017;11:784–93. https://doi.org/10.1017/S1751731116002020 .
13. Kong C, Adeola O. Evaluation of amino acid and energy utilization in feedstuff for swine and poultry diets. Asian-Australas J Anim Sci 2014;27:917–25. https://doi.org/10.5713/ajas.2014.r.02 .
14. Zhang F, Adeola O. Techniques for evaluating digestibility of energy, amino acids, phosphorus, and calcium in feed ingredients for pigs. Anim Nutr 2017;3:344–52. https://doi.org/10.1016/j.aninu.2017.06.008 .
15. Oliveira MSF, Htoo JK, Stein HH. The direct and difference procedures result in similar estimates for amino acid digestibility in feed ingredients fed to growing pigs. J Anim Sci 2020. 98skaa225. https://doi.org/10.1093/jas/skaa225 .
16. Adeola O. Digestion and balance techniques in pigs. In : Lewis AJ, Sothern LL, eds. Swine nutrition Second Edth ed. Boca Raton, FL, USA: CRC Press; 2000. p. 906.
17. AOAC. Official methods of analysis of AOAC International Gaithersburg, MD, USA: AOAC International; 2006.
18. Myers WD, Ludden PA, Nayigihugu V, Hess BW. Technical Note: A procedure for the preparation and quantitative analysis of samples for titanium dioxide. J Anim Sci 2004;82:179–83. https://doi.org/10.2527/2004.821179x .
19. Wu G. Functional amino acids in growth, reproduction, and health. Adv Nutr 2010;1:31–7. https://doi.org/10.3945/an.110.1008 .
20. Zhao Y, Weaver AC, Fellner V, Payne RL, Kim SW. Amino acid fortified diets for weanling pigs replacing fish meal and whey protein concentrate: Effects on growth, immune status, and gut health. J Anim Sci Biotechnol 2014;5:57. https://doi.org/10.1186/2049-1891-5-57 .
21. Wensley MR, Tokach MD, Woodworth JC, et al. Maintaining continuity of nutrient intake after weaning. II. Review of post-weaning strategies. Transl Anim Sci 2021. 5txab022. https://doi.org/10.1093/tas/txab022 .
22. Zheng L, Duarte ME, Sevarolli Loftus A, Kim SW. Intestinal health of pigs upon weaning: challenges and nutritional intervention. Front Vet Sci 2021;8:91. https://doi.org/10.3389/fvets.2021.628258 .
23. Shen YB, Weaver AC, Kim SW. Effect of feed grade L-methionine on growth performance and gut health in nursery pigs compared with conventional DL-methionine. J Anim Sci 2014;92:5530–9. https://doi.org/10.2527/jas.2014-7830 .
24. Bai M, Wang L, Liu H, et al. Imbalanced dietary methionine-to-sulfur amino acid ratio can affect amino acid profiles, antioxidant capacity, and intestinal morphology of piglets. Anim Nutr 2020;6:447–56. https://doi.org/10.1016/j.aninu.2020.03.009 .
25. Chalvon-Demersay T, Luise D, Le Floc’h N, et al. Functional amino acids in pigs and chickens: implication for gut health. Front Vet Sci 2021;8:663727. https://doi.org/10.3389/fvets.2021.663727 .
26. Koepke JR, Kaushik RS, Gibbons WR, Brown M, Levesque CL. Evaluation of a bioprocessed soybean meal on nursery pig performance and immune status. J Anim Sci 2017;95:5030–9. https://doi.org/10.2527/jas2017.1679 .
27. Li DF, Nelssen JL, Reddy PG, Blecha F, Klemm R, Goodband RD. Interrelationship between hypersensitivity to soybean proteins and growth performance in early-weaned pigs. J Anim Sci 1991;69:4062–9. https://doi.org/10.2527/1991.69104062x .
28. Yang YX, Kim YG, Lohakare JD, et al. Comparative efficacy of different soy protein sources on growth performance, nutrient digestibility and intestinal morphology in weaned pigs. Asian-Australas J Anim Sci 2007;20:775–83. https://doi.org/10.5713/ajas.2007.775 .
29. Shankar SK, Mulimani VH. Alpha-galactosidase production by Aspergillus oryzae in solid-state fermentation. Bioresour Technol 2007;98:958–61. https://doi.org/10.1016/j.biortech.2006.03.013 .
30. Pedersen C, Almeida JS, Stein HH. Analysis of published data for standardized ileal digestibility of protein and amino acids in soy proteins fed to pigs. J Anim Sci 2016;94:340–3. https://doi.org/10.2527/jas.2015-9864 .
31. Trindade Neto MA, Gallardo Vela C, Dadalt JC. Amino acid digestibility and energy use by weaned piglets fed yellow corn, sorghum and an exogenous enzymes combination. Livest Sci 2020;240:104126. https://doi.org/10.1016/j.livsci.2020.104126 .
32. Sauer N, Eklund M, Hoerner S, Rademacher M, Mosenthin R. Comparison of standardized ileal amino acid digestibilities in protein supplements and cereal grains for weaned pigs. J Anim Sci 2012;90:107–9. https://doi.org/10.2527/jas.53828 .
33. Stein HH, Pedersen C, Wirt AR, Bohlke RA. Additivity of values for apparent and standardized ileal digestibility of amino acids in mixed diets fed to growing pigs. J Anim Sci 2005;83:2387–95. https://doi.org/10.2527/2005.83102387x .
34. Cervantes-Pahm SK, Liu Y, Stein HH. Digestible indispensable amino acid score and digestible amino acids in eight cereal grains. Br J Nutr 2014;111:1663–72. https://doi.org/10.1017/S0007114513004273 .
35. Pedersen C, Boersma MG, Stein HH. Energy and nutrient digestibility in NutriDense corn and other cereal grains fed to growing pigs. J Anim Sci 2007;85:2473–83. https://doi.org/10.2527/jas.2006-620 .
36. Mahan DC. Evaluating two sources of dried whey and the effects of replacing the corn and dried whey component with corn gluten meal and lactose in the diets of weanling swine. J Anim Sci 1993;71:2860–6. https://doi.org/10.2527/1993.71112860x .
37. Moeser AJ, Pohl CS, Rajput M. Weaning stress and gastrointestinal barrier development: Implications for lifelong gut health in pigs. Anim Nutr 2017;3:313–21. https://doi.org/10.1016/j.aninu.2017.06.003 .
38. Lindemann MD, Cornelius SG, El Kandelgy SM, Moser RL, Pettigrew JE. Effect of age, weaning and diet on digestive enzyme levels in the piglet. J Anim Sci 1986;62:1298–307. https://doi.org/10.2527/jas1986.6251298x .
39. Stein HH, Sève B, Fuller MF, Moughan PJ, De Lange CFM. Invited review: amino acid bioavailability and digestibility in pig feed ingredients: terminology and application. J Anim Sci 2007;85:172–80. https://doi.org/10.2527/jas.2005-742 .
40. Xue PC, Ragland D, Adeola O. Determination of additivity of apparent and standardized ileal digestibility of amino acids in diets containing multiple protein sources fed to growing pigs. J Anim Sci 2014;92:3937–44. https://doi.org/10.2527/jas.2014-7815 .
41. González-Vega JC, Kim BG, Htoo JK, Lemme A, Stein HH. Amino acid digestibility in heated soybean meal fed to growing pigs. J Anim Sci 2011;89:3617–25. https://doi.org/10.2527/jas.2010-3465 .

Article information Continued

Table 1

Composition of experimental diets1) (as-fed basis)

Item FSD CBD NFD
Feedstuff (%)
Fermented soybean meal 20.00 - -
Corn, yellow - 92.62 -
Corn starch 62.72 - 69.37
Sucrose 10.00 - 20.00
Cellulose 3.50 - 5.00
Soy oil - 3.00 1.00
L-Lys HCl - 0.38 -
L-Thr - 0.08 -
L-Trp - 0.04 -
Vitamin premix2) 0.03 0.03 0.03
Mineral premix3) 0.15 0.15 0.15
Magnesium oxide - - 0.10
Potassium carbonate - - 0.40
Salt 0.40 0.30 0.40
Dicalcium phosphate 2.00 2.35 2.60
Limestone 0.70 0.55 0.45
Titanium dioxide 0.50 0.50 0.50
Total 100.00 100.00 100.00
1)

FSD, a diet with 20% fermented soybean meal (Pepsoygen, Nutraferma Inc., North Sioux City, SD, USA); CBD, a corn basal diet; NFD, a semi-purified N free diet to measure basal endogenous AA losses; CFD, a mixture of corn and fermented soybean meal diet (80% of CBD and 20% fermented soybean meal).

2)

The vitamin premix provided per kilogram of complete diet: 6,614 IU of vitamin A as vitamin A acetate, 992 IU of vitamin D3, 19.8 IU of vitamin E, 2.64 mg of vitamin K as menadione sodium bisulfate, 0.03 mg of vitamin B12, 4.63 mg of riboflavin, 18.52 mg of D-pantothenic acid as calcium panthonate, 24.96 mg of niacin, and 0.07 mg of biotin.

3)

The trace mineral premix provided per kilogram of complete diet: 33 mg of Mn as manganous oxide, 110 mg of Fe as ferrous sulfate, 110 mg of Zn as zinc sulfate, 16.5 mg of Cu as copper sulfate, 0.30 mg of I as ethylenediamine dihydroiodide, and 0.30 mg of Se as sodium selenite.

Table 2

Analyzed composition of experimental diets1) (as-fed basis)

Item FSD CBD CFD NFD
DM (%) 95.56 92.38 91.41 95.71
CP (%) 10.83 7.26 17.33 0.44
NDF (%) 5.24 8.00 7.46 4.95
ADF (%) 4.30 2.62 3.09 4.53
Ca (%) 0.72 0.75 0.61 0.71
P (%) 0.49 0.73 0.67 0.52
Indispensable AA (%)
 Arg 0.69 0.37 1.06 0.01
 His 0.28 0.20 0.45 0.00
 Ile 0.55 0.26 0.78 0.01
 Leu 0.89 0.79 1.53 0.01
 Lys 0.68 0.54 1.14 0.03
 Met 0.15 0.16 0.29 0.00
 Phe 0.58 0.34 0.87 0.01
 Thr 0.43 0.33 0.70 0.01
 Trp 0.15 0.10 0.23 0.00
 Val 0.59 0.35 0.88 0.01
Dispensable AA (%)
 Ala 0.51 0.50 0.91 0.01
 Asp 1.27 0.49 1.70 0.01
 Cys 0.16 0.15 0.31 0.00
 Glu 2.02 1.23 2.98 0.02
 Gly 0.50 0.31 0.76 0.01
 Pro 0.55 0.58 1.02 0.03
 Ser 0.50 0.29 0.72 0.01
 Tyr 0.23 0.22 0.51 0.01
Total AA 11.06 7.52 17.15 0.44

DM, dry matter; CP, crude protein; NDF, neutral detergent fiber; ADF, acid detergent fiber; AA, amino acids.

1)

FSD, a diet with 20% fermented soybean meal (Pepsoygen, Nutraferma Inc., North Sioux City, SD, USA); CBD, a corn basal diet; CFD, a mixture of corn and fermented soybean meal diet (80% of CBD and 20% fermented soybean meal); NFD, a semi-purified N free diet to measure basal endogenous AA losses.

Table 3

Analyzed composition of test ingredients (as-fed basis)

Item (%) Corn Fermented soybean meal
Indispensable AA
 Arg 0.40 3.57
 His 0.22 1.29
 Ile 0.28 2.30
 Leu 0.85 4.09
 Lys 0.26 3.16
 Met 0.17 0.75
 Phe 0.37 2.71
 Thr 0.27 2.11
 Trp 0.06 0.61
 Val 0.38 2.55
Dispensable AA
 Ala 0.54 2.37
 Asp 0.53 5.91
 Cys 0.16 0.97
 Glu 1.33 9.32
 Gly 0.33 2.34
 Pro 0.63 2.97
 Ser 0.31 2.74
 Tyr 0.24 1.74

AA, amino acids.

Table 4

Apparent ileal digestibility of amino acids in experimental diets

Item (%) Treatment1) SEM p-value

FSD CBD CFD
Indispensable AA
 Arg 84.6c 55.5a 73.8b 2.9 <0.001
 His 86.0c 44.9a 61.9b 3.3 <0.001
 Ile 85.0c 37.7a 64.3b 3.8 <0.001
 Leu 83.8b 50.5a 58.6a 4.5 <0.001
 Lys 81.6b 65.3a 69.3a 3.4 <0.001
 Met 85.4b 60.3a 63.9a 4.7 <0.001
 Phe 85.4c 44.0a 62.8b 3.8 <0.001
 Thr 72.9c 29.2a 45.0b 4.9 <0.001
 Trp 80.7c 51.9a 64.6b 3.6 <0.001
 Val 79.1c 30.5a 53.0b 3.9 <0.001
Dispensable AA
 Ala 77.0b 44.1a 48.2a 4.1 <0.001
 Asp 83.4c 33.4a 63.6b 3.1 <0.001
 Cys 73.1b 36.1a 43.8a 4.6 <0.001
 Glu 85.9c 51.6a 65.6b 3.3 <0.001
 Gly 42.6c −55.7a 5.4b 15.3 <0.001
 Pro 56.7 38.9 48.9 6.5 0.128
 Ser 79.8c 31.6a 53.5b 3.9 <0.001
 Tyr 74.6c 40.7a 58.6b 4.9 <0.001
Total AA 79.3c 40.8a 57.0b 3.5 <0.001

SEM, standard error of the mean; AA, amino acids.

1)

FSD, pigs fed a diet with 20% fermented soybean meal (Pepsoygen, Nutraferma Inc., North Sioux City, SD, USA); CBD, pigs fed a corn basal diet; CFD, pigs fed a mixture of corn and fermented soybean meal diet (80% of CBD and 20% fermented soybean meal).

a–c

Means in the same row with different superscripts are different (p<0.05).

Table 5

Basal endogenous losses of amino acids of nursery pigs fed an N-free diet

Item (g/kg dry matter intake) Basal endogenous losses of AA SEM
Indispensable AA
 Arg 0.56 0.09
 His 0.16 0.02
 Ile 0.32 0.06
 Leu 0.53 0.10
 Lys 0.42 0.09
 Met 0.09 0.02
 Phe 0.32 0.06
 Thr 0.52 0.07
 Trp 0.13 0.02
 Val 0.55 0.07
Dispensable AA
 Ala 0.54 0.08
 Asp 0.74 0.12
 Cys 0.14 0.02
 Glu 0.97 0.18
 Gly 1.93 0.21
 Pro 3.09 0.83
 Ser 0.45 0.05
 Tyr 0.23 0.04
Total AA 12.12 1.66

AA, amino acids; SEM, standard error of the mean.

Table 6

Standardized ileal digestibility of amino acids in experimental diets

Item (%) Treatment1) SEM p-value

FSD CBD CFD
Indispensable AA
 Arg 91.7b 80.7a 79.9a 3.1 0.005
 His 90.3b 61.4a 65.1a 3.4 <0.001
 Ile 89.7b 62.6a 69.0a 3.9 <0.001
 Leu 88.8b 65.9a 62.1a 4.7 <0.001
 Lys 87.1b 81.5ab 74.0a 3.4 0.005
 Met 90.0b 72.5a 66.7a 5.0 <0.001
 Phe 90.1b 64.2a 66.9a 4.7 <0.001
 Thr 83.6b 59.1a 53.3a 4.9 <0.001
 Trp 89.0b 76.5a 71.7a 3.6 <0.001
 Val 87.3b 60.2a 60.0a 4.2 <0.001
Dispensable AA
 Ala 85.7b 64.6a 54.1a 4.3 <0.001
 Asp 88.1b 63.0a 68.7a 3.2 <0.001
 Cys 80.2b 57.5a 48.5a 5.0 <0.001
 Glu 89.9b 68.9a 69.2a 3.3 <0.001
 Gly 81.1b 43.5a 35.6a 15.2 0.013
 Pro 104.8b 100.2ab 78.3a 7.6 0.023
 Ser 87.1b 59.9a 60.0a 4.1 <0.001
 Tyr 84.3c 50.5a 62.9b 4.5 <0.001
Total AA 89.8b 55.7a 63.6a 3.4 <0.001

SEM, standard error of the mean; AA, amino acids.

1)

FSD, pigs fed a diet with 20% fermented soybean meal (Pepsoygen, Nutraferma Inc., North Sioux City, SD, USA); CBD, pigs fed a corn basal diet; CFD, pigs fed a mixture of corn and fermented soybean meal diet (80% of CBD and 20% fermented soybean meal).

a–c

Means in the same row with different superscripts are different (p<0.05).

Table 7

Apparent ileal digestibility of amino acids in fermented soybean meal calculated using direct and difference procedures

Item (%) Direct procedure Difference procedure Pooled SEM p-value
Indispensable AA
 Arg 84.1 84.9 7.4 0.919
 His 86.0 73.3 6.0 0.073
 Ile 84.0 87.3 6.8 0.646
 Leu 83.0 64.0 8.1 0.052
 Lys 81.5 75.1 9.0 0.498
 Met 84.0 66.6 10.2 0.131
 Phe 84.7 73.9 6.4 0.136
 Thr 73.3 44.3 9.4 0.017
 Trp 81.0 78.5 6.9 0.732
 Val 78.9 67.0 8.7 0.212
Dispensable AA
 Ala 76.7 45.3 7.9 0.005
 Asp 83.4 75.3 6.4 0.244
 Cys 73.1 34.2 13.5 0.024
 Glu 85.9 73.1 5.8 0.061
 Gly 45.0 24.8 16.4 0.260
 Pro 56.7 43.8 29.4 0.674
 Ser 79.9 50.4 6.8 0.003
 Tyr 73.6 59.1 12.4 0.282

SEM, standard error of the mean; AA, amino acids.

Table 8

Standardized ileal digestibility of amino acids in fermented soybean meal calculated using direct and difference procedures

Item (%) Direct procedure Difference procedure Pooled SEM p-value
Indispensable AA
 Arg 91.8 90.0 7.4 0.818
 His 91.5 83.3 6.0 0.217
 Ile 89.7 95.3 6.8 0.437
 Leu 88.6 73.7 8.1 0.107
 Lys 87.5 83.3 9.0 0.656
 Met 89.8 75.1 10.2 0.191
 Phe 90.0 81.7 6.4 0.237
 Thr 84.9 59.1 9.4 0.028
 Trp 89.3 90.4 6.9 0.874
 Val 87.8 78.6 8.7 0.323
Dispensable AA
 Ala 86.8 59.4 7.9 0.010
 Asp 89.0 83.5 6.4 0.420
 Cys 81.7 50.5 13.5 0.054
 Glu 90.5 80.7 5.8 0.131
 Gly 81.8 48.0 16.4 0.079
 Pro 110.4 66.0 29.4 0.175
 Ser 88.5 59.9 6.8 0.004
 Tyr 83.3 68.1 12.4 0.262

SEM, standard error of the mean; AA, amino acids.