Ileal Digestibility Values Research Articles

Digestible Indispensable Amino Acid Scores (DIAAS) of Six Cooked Chinese Pulses.

Values for the digestible indispensable amino acid score (DIAAS) of a protein are based on true ileal amino acid (AA) digestibility values obtained in adult humans or in the growing pig as an animal model. An experiment was conducted using growing pigs to determine the true ileal digestibility (TID) values of AA in six cooked Chinese pulses (kidney bean, mung bean, adzuki bean, broad beans, peas and chickpeas). Each pulse was included in a diet as the only source of crude protein (CP). An N-free diet was given to allow determination of gut endogenous AA losses. Seven growing pigs each fitted with a T-cannula at the terminal ileum were allotted to a 7 by 6 incomplete Latin square with seven diets and six 7-d periods. The true digestibility values % for the total indispensable AA were higher (p < 0.001) for broad beans (87.3 ± 2.98) and lower (p < 0.001) for kidney bean (73.3 ± 4.84) than for the other pulses. For the older child (over 3 years), adolescent and adult, the DIAAS (%) was 88 for kidney bean, 86 for mung bean, 76 for chickpeas, 68 for peas, 64 for adzuki bean and 60 for broad beans.

PSVIII-34 Late-Breaking Abstract: Additivity of digestible amino acids in hatchery byproducts fed to nursery pigs

Abstract The objectives were to determine standardized ileal digestibility (SID) of amino acids (AA) in hatchery byproducts fed to nursery pigs and to test the additivity of ileal digestible AA concentrations in hatchery byproducts. Ten barrows (initial body weight = 11.3 ± 1.3 kg) surgically fitted with T-cannulas at the distal ileum were individually housed in pens. Four diets were prepared to contain 30% of infertile eggs, unhatched eggs, culled chicks, or a mixture (20% dried infertile eggs + 20% dried unhatched eggs + 60% dried culled chicks) as the sole source of nitrogen. A nitrogen-free diet was additionally prepared to measure basal endogenous losses of AA. All experimental diet contained 0.5% chromic oxide as an indigestible index. Ten pigs were assigned to a replicated 5 × 4 Latin square design with 5 diets and 4 periods. Each period consisted of a 5-d adaptation period and a 2-d collection period. The hypothesis was that the determined digestible AA concentrations of the mixture are not different from the calculated values based on digestible AA in the individual ingredients. A t-test was used to determine the additivity of digestible AA concentrations in individual ingredients. Infertile eggs had greater (P &amp;lt; 0.05) SID of all indispensable AA except for lysine and methionine compared with culled chicks. The SID of all indispensable AA except for tryptophan was not different between culled chicks and the mixture. The calculated apparent and standardized ileal digestible AA in the mixture were not different from the determined values, but calculated ileal digestible tryptophan in the mixture was less (P &amp;lt; 0.05) than the measured value. In conclusion, ileal digestibility of most indispensable AA in infertile eggs is greater than that in culled chicks and ileal digestible AA values are additive in the mixture except for tryptophan.

Crystalline amino acids do not influence calculated values for standardized ileal digestibility of amino acids in feed ingredients included in diets for pigs.

An experiment was conducted to test the hypothesis that addition of crystalline amino acids (AA) to diets during the adaptation or collection periods will not influence calculated values for apparent ileal digestibility (AID) or standardized ileal digestibility (SID) of AA in corn and soybean meal (SBM). Seven ileal-cannulated barrows (initial body weight: 77.9 ± 2.6 kg) were allotted to a 7 × 7 Latin Square design with 7 dietary treatments and 7 periods. Dietary treatments included feeding diets based on corn or SBM without or with crystalline AA for the entire 7-d period or with crystalline AA during the adaptation period, but without crystalline AA during the collection period. An N-free diet was also used. Each experimental period consisted of 5 d of adaptation to the diets followed by 2 d of ileal digesta collection, with digesta being collected for 9 hr/d starting after feeding the morning meal. Thus, the entire experiment lasted 49 d. The AID and SID of crude protein (CP) and AA were calculated using values determined in corn or in SBM without or with crystalline AA to determine if crystalline AA influenced calculated values for AID or SID of CP and AA. Results indicated that addition of crystalline AA to diets fed during the entire 7-d period increased (P < 0.05) AID of some AA in corn and SBM. However, no differences in SID of CP and AA were observed between pigs fed the diets without crystalline AA and pigs fed the diets with crystalline AA if dietary crystalline AA were ignored in calculations of SID values. This indicates that crystalline AA were 100% absorbed before the distal ileum and did not affect calculated values for SID of AA if calculations were based only on the AA in corn or SBM. Therefore, it is concluded that crystalline AA may be added to experimental diets in digestibility experiments before and during collection periods without affecting results, if crystalline AA are disregarded in the calculation of AID or SID of AA in ingredients.

Apparent total tract and ileal amino acids digestibility values of vegetal protein meals with dietary protease to broiler diet.

This experiment was carried out to study the effect of dietary exogenous monocomponent protease on the coefficient apparent total tract (ATTD) and apparent ileal (AID) digestibility of amino acids of corn, soybean meal (SBM), and full fat soybean meal (FFSM) in broilers. A total of 400 males Cobb-500 (14 d of age) were equally allocated in 80 metabolic cages (50 cm × 50 cm × 45 cm) in a completely randomized design and a semi-controlled environment. Eight treatments (basal diet with or without a protease and three ingredients replacing the basal diets in 40% to corn and 30% to SBM and FFSM, with and without protease), with 10 replicates each were evaluated. The protease was added at 200 mg/kg resulting in 15,000 unit of PROT/kg. The total collection of excreta was held during 3 d, after 5 d for adaptation of broilers at the diets. The ileal content was collected on d 21, after slaughter of birds. The enzyme increased (P < 0.05) the ATTD and AID of most amino acids contained in SBM and FFSM. The digestibility of cysteine, glycine, proline, and threonine had higher (P < 0.05) ATTD and AID in all tested ingredients with the use of protease. On average, the dietary protease increased in 5.19% and 3.86% the total and ileal digestibility of amino acids, respectively. It was concluded that the dietary protease exerts major effects on toasted full-fat soybean, followed by soybean meal and corn to broilers.

The direct and difference procedures result in similar estimates for amino acid digestibility in feed ingredients fed to growing pigs.

An experiment was conducted to test the hypothesis that values for standardized ileal digestibility (SID) of amino acids (AA) in corn, wheat, and wheat middlings obtained using the direct procedure are not different from values obtained using the difference procedure. Sixteen ileal-cannulated barrows (initial BW: 69.5 ± 5.0 kg) were allotted to a replicated 8 × 4 Youden Square design with 8 diets and 4 periods. Each period consisted of 5 d of adaptation to the diet and 2 d of collection of ileal digesta. Four diets were based on soybean meal (SBM), corn, wheat, or wheat middlings as the only AA-containing ingredients. Three additional diets were based on a mixture of SBM and corn, SBM and wheat, or SBM and wheat middlings, and an N-free diet was also used. The apparent ileal digestibility (AID) and the SID of crude protein (CP) and AA for the 4 diets containing SBM, corn, wheat, or wheat middlings as the sole source of AA were calculated using the direct procedure. The AID and SID of CP and AA for the 3 mixed diets containing SBM and corn, wheat, or wheat middlings were also calculated and the contribution of digestible AA from SBM was subtracted from the AID or SID values for the diets. The AID or SID of AA in corn, wheat, and wheat middlings were subsequently calculated by difference. Results indicated that the AID values for a few AA were lower (P < 0.05) if the direct procedure was used instead of the difference procedure, regardless of ingredient. The AID of Trp was greater in corn and wheat middlings, and the SID of Trp in corn and wheat middlings tended to be greater, if the direct procedure rather than the difference procedure was used, but that was not the case for wheat (interaction, P < 0.05 and P < 0.10, respectively). However, for all other indispensable AA, and for most of the dispensable AA, the SID of AA in corn, wheat, and wheat middlings was not different between the difference procedure and the direct procedure. Therefore, values for SID of AA in cereal grains and fiber-rich ingredients may be determined using either the direct or the difference procedure.

Evaluation of energy and amino acids of brown rice and its effects on laying performance and egg quality of layers.

Two experiments were conducted to determine apparent metabolizable energy (AME), nitrogen-corrected AME (AMEn), and ileal digestible amino acid (AA) content of brown rice (BR) and to investigate the effect of dietary supplementation of BR on laying performance and egg quality of laying hens. In Exp. 1, 72 Hy-line Brown layers (49-week-old) were allocated to two treatments using a completely randomized block design, and each treatment included six cages per treatment and six hens per cage. A semi-purified diet was formulated to include BR as the sole source of AA and energy and an N-free diet was used to determine basal endogenous loss of AA. The hens were fed a commercial layer diet for adaptation to the experimental environment and diet for 7 days from d 0, and then fed experimental diets for 5 days from d 7. Excreta were collected from d 10 to 11 and ileal digesta were collected on d 12. On a dry matter (DM) basis, the AME and AMEn of BR was determined at 3,773 and 3,729 kcal/kg, respectively. The apparent ileal digestibility (AID) of BR ranged from 32.7% for Thr to 73.7% for Arg. The range of the standardized ileal digestibility (SID) value was between 79.4% for Met and 96.6% for Lys. In Exp. 2, 252 Hy-line Brown layers (44-week-old) were divided into four groups, comprising seven replicates of nine birds each and assigned to four experimental diets containing 0 (Control), 5%, 10%, or 15% BR for 5 weeks. The BR-containing diets were formulated to be equal in the content of AMEn and digestible AA to those of the diet without BR. No significant differences were observed in laying performances. Egg quality and blood profiles were not linearly or quadratically affected by dietary treatments. These results suggest that up to 15% BR can be included into layer feed without any adverse effects on laying performance and egg quality, if its energy and digestible AA values are well evaluated.

Effects of dietary protein levels and protease supplementation on growth performance, carcass traits, meat quality, and standardized ileal digestibility of amino acid in Pekin ducks fed a complex diet

This study aimed to investigate to the effects of dietary CP levels and protease supplementation on growth performance, carcass traits, meat quality, nutrients utilization, and standardized ileal digestibility of amino acid in Pekin ducks fed a complex diet. A total of 960 14-day-old male ducks were weighed and randomly allotted to a 2 × 5 factorial arrangement of 10 treatments with 6 replicate pens per treatment and 16 ducks per pen fed to 49 D of age. Experimental factors included five dietary CP levels ranging from 13.5 to 17.5% and with or without protease (200 mg/kg) supplementation. Between day 28 to 34, the digestible and metabolizable trials were performed. Significant CP × protease interactions (P < 0.05) on breast meat yield, DM, energy and nitrogen utilization, as well as standardized ileal digestibility values of 7 amino acids were observed. Regardless of protease supplementation, ducks fed 13.5, 14.5, and 15.5% CP had a poorer (P < 0.05) growth performance and breast meat yield than ducks fed with 16.5 and 17.5% CP. Ducks fed 13.5% CP had a positive effect (P < 0.05) on meat quality, dietary DM, energy and nitrogen utilization as well as standardized ileal digestibility of amino acids. Protease supplementation increased (P < 0.05) DM and phosphorus retention and decreased (P < 0.05) shear force of breast meat, regardless of CP level; when CP = 14.5%, protease significantly increased (P < 0.05) breast muscle yield. The optimal CP requirement without or with protease supplementation for BWG and FI were 17.02 or 16.53% and 16.64 or 16.75%, respectively, based on linear broken-line regression.

Unresolved issues for amino acid digestibility in poultry nutrition

Summary The purpose of this article is to review and discuss several issues concerning amino acid digestibility in poultry nutrition which are not totally resolved. Some issues are more resolved than others. These issues are as follows: Which method should be used to determine amino acid digestibility? Are amino acid digestibility values determined with cecectomized roosters similar to and interchangeable with broiler chicken ileal digestibility values? Should apparent or standardized amino acid digestibility values be used in feed formulation (which is preferable?)? which type of basal endogenous amino acid correction should be used for standardized amino acid digestibility values? Which type of indigestible marker should be used and how should digestibility values be calculated when using a marker? What to do about the effect of bird age on amino acid digestibility in feed formulation? And, what values should be used for digestible amino acid requirements?

Protein Quality Assessment of Follow-up Formula for Young Children and Ready-to-Use Therapeutic Foods: Recommendations by the FAO Expert Working Group in 2017

The FAO of the UN convened an Expert Working Group meeting to provide recommendations related to protein quality evaluation of Follow-up Formula for Young Children (FUF-YC) and Ready-to-Use Therapeutic Foods (RUTFs). The protein and amino acid (AA) scoring patterns for the target age groups were defined and recommendations provided on the use of currently available protein and indispensable AA digestibility data. For FUF-YC, an age category of 1-2.9 y was identified, and a matching protein requirement of 0.86g · kg-1 · d-1 with corresponding AA requirements were recommended. For RUTF, the protein requirement recommended was 2.82g · kg-1 · d-1, to achieve a catch-up weight gain of 10g · kg-1 · d-1 in children recovering from severe acute malnutrition. The AA requirements were factorially derived based on the adult protein requirement for maintenance and tissue AA composition. A flowchart was proposed for the best available methods to estimate digestibility coefficients (of either protein or AAs), in the following order: human, growing pig, and rat true ileal AA digestibility values. Where this is not possible, fecal protein digestibility values should be used. The Expert Working Group recommends the use of the Protein Digestibility Corrected Amino Acid Score (PDCAAS), with existing protein digestibility values, or the Digestible Indispensable Amino Acid Score provided that individual AA digestibility values are available for protein quality evaluation using the latter score. The Group also recommends the use of ileal digestibility of protein or of AAs for plant-based protein sources, recognizing the possible effects of antinutritional factors and impaired gut function. A PDCAAS score of ≥90% can be considered adequate for these formulations, whereas with a score <90%, the quantity of protein should be increased to meet the requirements. Regardless of the protein quality score, the ability of formulations to support growth in the target population should be evaluated. Future research recommendations are also proposed based on the knowledge gaps identified.

Digestible Indispensable Amino Acid Score (DIAAS) better Estimates the Protein Value of Pistachios than Digestibility Corrected Amino Acid Score (PDCAAS)

AbstractPistachios (Pistacia Vera) are nutrient-dense foods with a healthy nutritional profile that contains fiber, unsaturated fatty acids, essential nutrients, phytochemicals and protein. However, the nutritional quality of the protein has not been characterized to date. Therefore, the objective of this study was to determine the Protein Digestibility Corrected Amino Acid Score (PDCAAS) and Digestible Indispensable Amino Acid Score (DIAAS) for raw and roasted American pistachio nuts in growing pigs. The values for apparent ileal digestibility (AID) of crude protein (CP) and the standard ileal digestibility (SID) where calculated for these proteins. The CP content was greater for raw pistachios (27.1%) compared with roasted pistachios (25.1%). The amino acid (AA) in greatest concentrations for both types of pistachio were arginine followed by leucine. The AA in the lowest concentration were tryptophan followed by methionine. The AID of CP was greater (P &lt; 0.05) for raw pistachios than for roasted pistachios, and the AID of most indispensable AA (IAA), except arginine, isoleucine, and phenylalanine, was greater (P &lt; 0.05) for raw pistachios. The SID of CP was greater (P &lt; 0.05) for raw than for roasted pistachios, and the SID of all IAA, except phenylalanine, was greater (P &lt; 0.05) for raw than for roasted pistachios. The PDCAAS value calculated for both types of pistachios was based on the requirement for children from 2 to 5 years old (FAO, 1991), whereas the DIAAS value was calculated based on the requirement for children 3 years and older, adolescents, and adults (FAO, 2013). Both raw and roasted pistachios had a PDCAAS value of 75. In contrast, the DIAAS was numerically greater for raw pistachios than for roasted pistachios with values of 86 and 83, respectively. For PDCAAS, the first limiting AA in both raw and roasted pistachios when compared with the AA requirements for children 2 to 5 years was threonine. For DIAAS, lysine was the first limiting AA in both raw and roasted pistachios when compared with the AA requirements for children 3 years and older, adolescents, and adults. Based on the DIAAS cut-off values describing protein quality (FAO, 2013), raw pistachios and roasted pistachios can both be considered a ‘Good’ quality protein if consumed by children older than 3 year, adolescents, and adults.

Predicting the standardized ileal digestibility of crude protein in feather meal fed to broiler chickens using a pH-stat and a FT-Raman method

The present study assessed the suitability of a three-enzyme pH-stat method and of novel FT-Raman methods to predict the ileal digestibility of crude protein (CP) in feather meals (FeMs). A broiler digestibility trial was conducted to assess the ileal digestibility of crude protein in nine FeMs of different origins. One of the nine FeMs (FeM9) was the pre-treated ingredient stream of a commercially available FeM (FeM8). The pre-treatment was previously developed in our laboratory and consists of incubating FeM in 200% distilled water (%FeM w/w), with 0.5% of a commercial protease (%FeM w/w) and 2% sodium sulphite (%FeM w/w) at 55 °C for 24 hr in a shaking incubator. The degree of hydrolysis (DH) was measured after 10 minutes using a three-enzyme pH-stat method. Levels of disulphide conformers trans-gauche-trans (SStgt), gauche-gauche-trans (SSggt) and gauche-gauche-gauche (SSggg) in the nine FeMs were studied by means of FT-Raman. The effects of the disulphide conformers and of their interactions on AIDCP and SIDCP in FeM were assessed by analysis of variance (ANOVA) and fitted using a third-order interaction model.The coefficient of apparent ileal digestibility of CP (AIDCP) in the FeMs ranged from 0.368 to 0.594, whereas the coefficient of standard ileal digestibility of CP (SIDCP) ranged from 0.398 to 0.644. The pre-treatment significantly improved (P < 0.05) the AIDCP and SIDCP in FeM8 from 0.499 to 0.594 and from 0.546 to 0.644, respectively. DH correlated positively with AIDCP (R2 = 0.50, P < 0.05) and SIDCP (R2 = 0.49, P < 0.05). Significant (P < 0.05) positive linear relationships existed between total disulphide bonds and the ileal digestibility of CP in FeMs. All three types of disulphide conformers, as well as their interactions, had a significant effect (P < 0.05) on the ileal digestibility of CP in FeM. Third-order interaction models enabled predictions equation based on all three disulphide levels, with regression coefficients (R2) of 0.675 for AIDCP (P < 0.05) and 0.674 (P < 0.05) for SIDCP. Positive linear regression analysis of the predicted values of ileal digestibility of CP with the observed values of ileal digestibility of CP in FeMs in the two models revealed significant (P < 0.05) correlation coefficients (R2) of 0.96 and 0.93 for AIDCP and SIDCP, respectively.This study highlights that the ileal digestibility of CP in FeM is greatly affected by the disulphide bond conformers present, which can be used as predictors of AIDCP and SIDCP.

Amino acid composition and digestible amino acid content in animal protein by-product meals fed to growing pigs1.

An industry survey and animal experiment were conducted to evaluate the amino acid (AA) compositional variability and standardized ileal digestibility (SID) of AA in animal protein by-products fed to growing pigs. Animal protein by-product meals (212) were categorized into 8 groupings (blood meal, chicken by-product meal, chicken meal, feather meal, meat and bone meal, meat meal, poultry by-product meal, and poultry meal) and analyzed for total AA. Amino acid analysis among (e.g., Lys in blood meal averaged 9.20% compared with 2.31% for feather meal, DM basis) and within (e.g., Lys range of 1.54% in blood meal and 1.44% in feather meal, DM basis) the by-product classifications varied as expected, but on average the total AA values were similar to that reported in the literature. For the determination of the SID of AA, 15 barrows (average initial and final BW of 31.6 and 78.7 kg, respectively) were fitted with a T-cannula in the distal ileum and allotted to 15 diets over nine 7-d periods, resulting in 9 replications per diet. Pigs were fed a basal diet based on soybean meal and dehulled-degermed corn, 13 diets containing 17.5% animal protein by-product meal to partially replace a portion of the soybean meal and dehulled-degermed corn in the basal diet, or a N-free diet. Pigs were re-allotted to diets based on minimizing the number to times that the N-free diet would precede or follow feeding either of the blood or feather meal diets because of concern with inadequate diet consumption, as well as to prevent diets from being re-fed to the same pig during the next or subsequent periods. Values for the apparent ileal AA digestibility of each diet were determined, adjusted to SID based upon the endogenous AA losses determined by feeding the N-free diet, and the SID of AA in each animal protein by-product meal calculated using the difference procedure. The SID of AA varied among (e.g., SID of Lys averaged 91% in chicken meal but 47% in feather meal) and within (e.g., SID of Lys in three meat and bone meals was 80%, 71%, and 54%) the animal protein by-product meals, as would be expected and are consistent with variation reported in the literature. Overall, the data provide total AA composition for 212 samples and SID of AA for 13 samples of animal protein by-product meals, including data on their variability, which is critical for their use in feed formulation programs.

Can the digestible indispensable amino acid score methodology decrease protein malnutrition.

Protein undernutrition is a serious global problem that results in stunted growth, disease, and premature death in millions of people annually. Protein deficiency is caused by a deficiency in specific indispensable amino acids and efforts to alleviate protein malnutrition, therefore, need to focus on the provision of adequate quantities of digestible indispensable amino acids. The digestibility of amino acids is most correctly determined at the end of the small intestine, and digestibility values obtained using this approach are termed “ileal digestibility values.” The total protein provision to an individual is based on the sum of digestible indispensable amino acids consumed in a meal. The protein quality of a single ingredient is less important than the quality of the mixed meal that is consumed. To assist in calculating the protein quality of meals for humans, the FAO recommends that a system called the “Digestible Indispensable Amino Acid Score” or DIAAS be used. This system is based on the ileal digestibility of each amino acid in individual protein foods, but allows for the calculation of the quality of a meal consisting of a number of protein foods. The system can then be used to assess the quality of total protein intake consumed as a meal. Comparison of this value to the requirements for indispensable amino acids by humans can be used to estimate an individual’s protein status.

Additivity of apparent and standardized ileal amino acid digestibility of corn and soybean meal in broiler diets.

A total of 144 male Ross 308 broiler chickens were used in a digestibility bioassay to determine the additivity of apparent or standardized amino acid (AA) digestibility values for corn, soybean meal (SBM), or a mixture of corn and SBM. Following the receipt of a standard commercial starter diet from days 1 to 21, broilers were divided into 4 treatments (6 cages per treatment; 6 birds per cage) and received semi-purified diets based on corn, SBM, or a mixture of corn and SBM or a nitrogen-free diet (for the estimation of basal endogenous AA losses). Apparent and standardized ileal AA digestibility values were determined on day 28 and the measured values for the mixture of corn and SBM were statistically compared to calculated values based on the digestibility of the individual raw materials and their concentration in the mixed diet. The use of apparent ileal AA digestibility values for single ingredients resulted in an underestimation (P < 0.05) of the digestibility of the mixed feed for nitrogen, Lys, Arg, Thr, Asp, and Gly. Correction of apparent digestibility values to standardized values entirely corrected the underestimation in the mixed feed and resulted in a predictable linearity from single ingredients to the mixed diet. It can be concluded that standardized ileal AA digestibility values are more additive than apparent values and should be used, where possible, to enhance the accuracy of feed formulation and reduce both the diet cost and the environmental impact of nitrogenous pollution.

116 Direct vs. difference method to determine amino acid digestibility in ingredients fed to pigs

Abstract An experiment was conducted to test the hypothesis that values for standardized ileal digestibility (SID) of amino acids (AA) in cereal grains and fiber rich ingredients obtained using the direct method are not different from values obtained using the difference method. Sixteen ileal-cannulated barrows (69.45 ± 5.01 kg) were allotted to an 8 diets × 4 period Youden square design. Each period consisted of 5 d of adaptation and 2 d of ileal digesta collection. Four diets were based on soybean meal (SBM), corn, wheat, or wheat middlings as the only AA-containing ingredients. Three additional diets were based on a mixture of SBM and corn, wheat, or wheat middlings and a N-free diet was also used. The SID of AA in the 4 diets containing SBM, corn, wheat, or wheat middlings as the sole source of AA were calculated using the direct method. The SID of AA in corn, wheat, and wheat middlings were also calculated by difference from the 3 diets containing SBM and corn, wheat, or wheat middlings by subtracting the contribution from SBM of each AA from the SID values for the mixed diet. Data were analyzed using a model that included the method of determination of AA digestibility as the fixed effect, and pig and period as random effects. There was no difference between the direct and the difference method for the SID of most AA in corn, wheat, and wheat middlings, although the SID of Trp was lower (P &lt; 0.05) for the difference method than values derived by the direct method for both corn and wheat middlings (Table 1). Therefore, values for SID of AA in cereal grains or fiber-rich ingredients could be obtained using either the direct method or the difference method.

Comparison of two methods of protein quality evaluation in rice, rye and barley as food protein sources in human nutrition

Different foods differ in their protein quality, which is characterized by the content and digestibility of individual amino acids. The Food and Agriculture Organisation has recommended replacing the method for protein quality evaluation of foods called protein digestibility corrected amino acid score (PDCAAS) with the new method - digestible indispensable amino acid score (DIAAS), in which the values of ileal amino acid digestibility obtained in pigs are used. However, the information about DIAAS values of foods are limited. Therefore, the study on growing pigs was conducted to determine true fecal protein digestibility and standardized ileal amino acid digestibility of rice, rye and barley. Using these values, the PDCAAS and DIAAS were calculated and compared. A total of 18 gilts with a T-cannula inserted in the terminal ileum were allotted to 3 diets with six replicate pigs per diet. Three semi-purified diets were formulated to contain the tested cereal grains (rice, rye, barley) as the sole nitrogen source. Chromic oxide was used as indigestible marker. Each experimental period comprised of a 7-d adaptation period followed by 24 h collection of feces and ileal digesta. The content of nitrogen, dry matter and chromic oxide was analyzed in samples of diets, feces and ileal digesta. Moreover, in the samples of diets and ileal digesta the content of amino acids was determined. Calculated ratio of crude protein to lysine was greatest in rice (4.50) followed by rye (3.65) and the lowest one in barley (3.35). True fecal protein digestibility was greater when compared with ileal amino acid digestibility for all tested samples, thus suggesting an overestimation of protein quality determined by PDCAAS. Calculated PDCAAS values for rice, rye and barley (81, 65 and 61%) were generally greater than the DIAAS values (79, 56 and 55%), especially for the poorer quality protein sources such as rye and barley in comparison with rice. The lysine was the first limiting amino acid in all tested cereal grains. Based on the DIAAS evaluation, rice is better protein source in human nutrition in comparison with rye or barley.

Digestible indispensable amino acid scores of nine cooked cereal grains.

True ileal digestibility (TID) values of amino acid (AA) obtained using growing rats are often used for the characterisation of protein quality in different foods and acquisition of digestible indispensable amino acid scores (DIAAS) in adult humans. Here, we conducted an experiment to determine the TID values of AA obtained from nine cooked cereal grains (brown rice, polished rice, buckwheat, oats, proso millet, foxtail millet, tartary buckwheat, adlay and whole wheat) fed to growing Sprague-Dawley male rats. All rats were fed a standard basal diet for 7 d and then received each diet for 7 d. Ileal contents were collected from the terminal 20 cm of ileum. Among the TID values obtained, whole wheat had the highest values (P&lt;0·05), and polished rice, proso millet and tartary buckwheat had relatively low values. The TID indispensable AA concentrations in whole wheat were greater than those of brown rice or polished rice (P&lt;0·05), and polished rice was the lowest total TID concentrations among the other cereal grains. The DIAAS was 68 for buckwheat, 47 for tartary buckwheat, 43 for oats, 42 for brown rice, 37 for polished rice, 20 for whole wheat, 13 for adlay, 10 for foxtail millet and 7 for proso millet. In this study, the TID values of the nine cooked cereal grains commonly consumed in China were used for the creation of a DIAAS database and thus gained public health outcomes.

Growth performance of nursery pigs fed diets containing increasing levels of a novel high-protein corn distillers dried grains with solubles.

The objective of this study was to use the recently determined ME and standardized ileal digestibility (SID) values of AA for a novel high-protein distillers dried grains with solubles (HP-DDGS; PureStream 40, Lincolnway Energy LLC, Nevada, IA) to determine the optimal dietary inclusion rates in diets for nursery pigs. Three hundred and sixty pigs (BW = 6.79 ± 0.02 kg) were blocked by BW, and pens within blocks were assigned randomly to one of four dietary treatments (10 pens/treatment, 9 pigs/pen). Dietary treatments consisted of adding 0%, 10%, 20%, or 30% HP-DDGS to nursery diets during phase 2 (days 7–21) and phase 3 (days 21–42) of a three-phase nursery feeding program. Diets within each phase were formulated to contain equivalent amounts of ME, SID Lys, Met, Thr, and Trp, Ca, standardized total tract digestible P, vitamins, and trace minerals. Calculated SID Leu to Lys ratios for 0%, 10%, 20%, and 30% HP-DDGS diets were 119%, 137%, 156%, and 173% in phase 2 diets and 120%, 131%, 143%, and 160% in phase 3 diets. The SID Ile to Lys ratios ranged from 60% to 69% in phase 2 diets and from 54% to 59% in phase 3 diets. The SID Val to Lys ratios ranged from 63% to 79% in phase 2 diets and 64% to 68% in phase 3 diets. Body weight and feed disappearance were measured weekly. During phase 2, ADG, ADFI, and G:F were reduced linearly (P < 0.01) as the diet inclusion rate of HP-DDGS increased. Similarly in phase 3, increasing dietary levels of HP-DDGS depressed ADG, ADFI, and G:F linearly (P < 0.01). Overall growth performance of phases 2 and 3 of nursery pigs was negatively affected by increasing levels of HP-DDGS in these diets. Pigs acquired a Streptococcus suis and Escherichia coli disease challenge during the experiment. Although no differences in morbidity were observed throughout the experiment, including HP-DDGS in diets tended to decrease (P = 0.08) mortality. In conclusion, a linear decrease in nursery pig growth performance was observed as increasing levels of HP-DDGS were added in diets, which was probably due to overestimation of SID AA content of the HP-DDGS, antagonistic effects of excess Leu, and the effects of relatively high fiber content.

The effect of drying method temperature, collection method, and marker type on apparent ileal amino acid digestibility in 21-day-old broilers fed corn-soybean meal-barley based diet.

For accurate estimation of nutrient digestibility, an ideal drying and sampling method is required to preserve the quality of the digesta. A standard corn-soybean meal (corn-SBM) broiler starter diet was fed from d 0 to 10 before birds were placed on the experimental diets until d 21. One hundred and sixty-eight male Cobb 500 broiler chicks were used to evaluate the effect of two drying methods (freeze-dryer vs. forced air-oven) and two drying temperatures (40vs. 55°C) (Exp 1), while ninety-six chicks were used to evaluate the effect of flushing and squeezing as well as marker types (titanium vs. chromium) on apparent ileal DM, N, Ca, P, and AA digestibility (Exp 2). There were seven (Exp 1) or eight (Exp 2) replicate cages per treatment with 6 birds/cage. Digesta from the distal two thirds of the ileum was obtained from birds following euthanasia on d 21 by squeezing (Exp 1) and squeezing or flushing (Exp 2). Samples collected were stored in the freezer at -20°C until they were either freeze-dried (FD) or oven-dried (OD) at 40 or 55°C. There were no interactions between the drying methods and drying temperatures (Exp 1) on apparent ileal DM, N, and AA digestibility. Met had the highest (92.3%) while Cys had the lowest (73.8%) digestibility value. In Exp 2, no interaction between sampling methods and marker types was observed. The effect of sampling methods was not significant except for Arg and Met where squeezing resulted in higher (P < 0.05) digestibility values. Furthermore, apparent ileal His, Ile, Cys, Ser, and Tyr digestibility tended to be higher (P < 0.1) in squeezed digesta compared to the flushed digesta. Results from these studies showed that OD ileal digesta at 40 or 55°C had no negative effect on apparent ileal AA digestibility. Likewise, marker type did not influence apparent ileal AA digestibility values.

Additivity of standardized ileal digestibility of amino acids in mixed diets containing multiple protein sources for growing pigs fed three crude protein levels.

This study was conducted to investigate the effect of dietary crude protein (CP) levels of semi-purified diets on the additivity of values for standardized ileal digestibility (SID) of amino acids (AA) in mixed diets from multiple protein sources for growing pigs. A total of 28 barrows (initial BW, 66.4±1.3kg) were surgically fitted with simple T-cannulas at the distal ileum and assigned to a replicated 14×4 incomplete Latin square design with 14 diets and 4 periods. The 14 experimental diets consisted of a nitrogen-free diet; a corn-based diet (80g CP/kg); nine semi-purified diets containing soya bean meal (SBM), canola meal (CM) or corn distillers dried grains with solubles (cDDGS), each type (protein source) of semi-purified diets supplied 80, 120 or 160g CP/kg, respectively; three mixed diets based on corn, SBM, CM and cDDGS formulated to contain 120, 160 and 200g CP/kg respectively. Pigs were fed each of the 14 diets during a seven-day period, and ileal digesta were collected from 08:00a.m to 6:00p.m on day 6 and 7. Chromic oxide was added as an indigestible marker. Results indicated that the SID of CP and AA were not affected by CP levels (p>.05). Values for SID of AA were additive (p>.05) with the exception of His and Lys; Arg and Lys; Arg, Lys, Thr, Asp, Cys and Gly in the mixed diets containing 120, 160 and 200g CP/kg respectively (p<.05). In conclusion, additivity of SID values of AA in the mixed diets at different CP levels was not affected by the CP levels of semi-purified diets for growing pigs. Therefore, it is recommended that SID values of AA should be used to formulate practical diets containing multiple ingredients for pigs.