Amino Acid Digestibility Values Research Articles

Standardized ileal digestibility of amino acids in Chinese fermented soybean meal from different sources fed to mid and late-gestating sows.

We determined apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values of crude protein (CP) and amino acids (AA) in fermented soybean meal from five different sources (FSBM 1 to 5) in China when fed to mid and late-gestating sows. Twenty-four parity four sows (12 at 30 d in gestation and 12 at 80 d in gestation) were fitted with a T-cannula in the distal ileum and used in this experiment. Sows were randomly assigned to a replicated 6 × 3 Youden square design including six diets and three periods. Six diets were provided for sows in mid and late gestation, including a nitrogen-free diet and five test diets containing 26% FSBM from different sources. Results showed that there were differences in AID and SID of CP among the different FSBM samples, but no differences between sow physiological stages were observed. Specifically, when mid-gestating sows were fed FSBM 2, the AID of CP was the lowest, whereas FSBM 3 exhibited a greater AID of CP when compared to the other FSBM samples (P < 0.01). Furthermore, during late gestation, FSBM 3 consistently had greater SID of CP when compared to other FSBM samples (P < 0.01). The ileal digestibility of most AA varied with different FSBM samples. In both mid and late gestation, differences (P < 0.05) were observed for AID of lysine, tryptophan, histidine, and arginine across different FSBM samples. Similarly, the AID of dispensable AA (cysteine, glutamine, and serine) also exhibited differences (P < 0.05) across different FSBM samples in both mid and late-gestating sows. For mid-gestating sows, SID differences relating to lysine, phenylalanine, tryptophan, threonine, and arginine were observed among different diets (P < 0.05). In late-gestating sows, SID values for lysine, tryptophan, leucine, and arginine differed across diets (P < 0.05). Furthermore, the ileal digestibility of some dispensable AA was influenced by physiological stage, as evidenced by greater AID and SID values for glycine, glutamine, cysteine, and serine in late-gestating sows when compared to mid-gestating sows (P < 0.01). In summary, our study determined AA ileal digestibility of different FSBM fed to mid and late-gestating sows. We observed that the AA ileal digestibility differed among five FSBM samples, but the physiological stage of sows did not affect the ileal digestibility of CP and most AA. Additionally, when formulating diets for sows, it is crucial to consider the nutritional value differences of FSBM.

Values for the Digestibility of Pea Protein Isolate or Casein Amino Acids Determined using the Dual Isotope Method Are Not Similar to Those Derived with the Standard Ileal Balance Method in Healthy Volunteers

BackgroundThe measurement of ileal amino acid (AA) digestibility is invasive and inappropriate when applied to vulnerable populations. The dual isotope method has been developed over the past 5 y as an alternative method. ObjectiveThe aim of this work was to compare the indispensable amino acid (IAA) digestibility values of 2 different proteins obtained using the dual isotope and the standard ileal balance methods in the same subjects. MethodsFifteen healthy adults completed the study. Over 4 h, they ingested 9 successive portions of mashed potatoes containing the test protein (pea protein or casein) labeled intrinsically with 15N and 2H, and a 13C-free AA mixture as a reference for the dual isotope method. Plasma was sampled regularly over the 8-h postprandial period, whereas the ileal digesta was collected continuously via a naso-ileal tube. Isotopic enrichments (15N and 13C) were measured in the digesta for the direct determination of ileal IAA digestibility, whereas plasma enrichments (2H and 13C) were measured to determine IAA digestibility using the dual isotope method. ResultsThe 4-h repeated meal procedure enabled the almost complete digestion of test proteins at 8 h and the attainment of a plasma isotopic plateau between 2.5 and 4 h. These conditions were necessary to perform the ileal balance and dual isotope methods simultaneously. For pea protein, the mean IAA digestibility was similar between the 2 methods, but significant differences (from 10% to 20%) were observed for individual IAA values. For casein, IAA digestibility was significantly lower with the dual isotope method for all the IAA analyzed. ConclusionsUnder our experimental conditions, the degree of agreement between the dual isotope and ileal balance methods varied among AAs and depended on the protein source. Further research is needed to validate the dual isotope method.This study was registered at clinicaltrials.gov as NCT04072770.

High-fiber diets for fattening pigs

Objective: To establish the feasibility and benefits of implementing high-fiber diets for pigs. Design/Methodology: A literature review of the practical application of pig diets with the inclusion of fibrous ingredients was carried out. Results: The formulation of high-fiber diets for pigs maintains or improves productive performance and provides additional gut health benefits. Study Limitations/Implications: Lack of information about the net energy and amino acid digestibility values of fibrous ingredients limits the proper formulation of pig diets. Findings/Conclusions: The inclusion of high-fiber ingredients in pig diets can partially replace traditional ingredients, consequently reducing costs and providing health benefits.

Determination of TMEn, standardized amino acid digestibility, phosphorus digestibility, and phosphorus bioavailability in conventional and reduced phosphorus distillers dried grains with solubles

The TMEn, amino acid (AA) digestibility, and P availability in 2 conventional corn distillers dried grains with solubles (C-DDGS1 and 2; 0.86 to 1.14% P, DM basis) and reduced phosphorus DDGS (RP-DDGS; 0.39% P) were evaluated. The TMEn of C-DDGS1 and 2 and RP-DDGS were determined in Experiment 1 using conventional adult Leghorn roosters, while standardized AA digestibility was determined in Experiment 2 using cecectomized roosters. Apparent ileal digestibility (AID) of P at different Ca levels was determined using precision-fed (crop intubation) broiler chickens in Experiments 3 and 4. The AID and total tract retention of P in C-DDGS2 were evaluated in Experiment 5 using ad libitum-fed broilers. Phosphorus bioavailability in C-DDGS2 relative to KH2PO4 based on bone ash was determined in Experiment 6. Experiments contained 4 to 5 replicates per treatment. In Experiment 1, the TMEn of C-DDGS1 and RP-DDGS was 3,428 and 2,840 kcal/kg, respectively (DM basis). In Experiment 2, there were no differences (P > 0.05) in rooster AA digestibility values between C-DDGS1 and RP-DDGS. In Experiment 3 with precision-fed chicks, AID of P in C-DDGS1 and RP-DDGS was 81 and 59%, respectively; there was no effect (P > 0.05) of increasing dietary Ca level from 0.04 to 1.0% for C-DDGS1 or reducing Ca from 1.5 to 1.0% for RP-DDGS. The AID of P in precision-fed chicks for C-DDGS2 in Experiment 4 was 48 and 80% at 1.3 and 0.3 Ca:total P ratios, respectively (P < 0.05). In Experiment 5, AID of P in C-DDGS2 at Ca:total P ratios of 1.3 and 2.5 was 63 and 42%, respectively, in precision-fed chicks. Regression of bone ash content (mg/tibia) on supplemental P intake in Experiment 6 yielded a P bioavailability of 61% relative to KH2PO4 for C-DDGS2. In conclusion, total and digestible P content in RP-DDGS was greatly reduced compared with C-DDGS, and the digestibility and bioavailability of the P in C-DDGS was affected by type of experimental assay and dietary Ca level.

Differential effects of milk proteins on amino acid digestibility, post-prandial nitrogen utilization and intestinal peptide profiles in rats

ObjectiveThe aim of this study was to analyze the protein digestibility and postprandial metabolism in rats of milk protein matrices obtained by different industrial processes. Material and methodsThe study was conducted on Wistar rats that consumed a meal containing different 15N-labeled milk proteins. Four milk matrices were tested: native micellar caseins (C1), caseins low in calcium (C2 low Ca2+), a matrix containing a ratio 63:37 of caseins and whey proteins (CW2) and whey proteins alone (W). Blood and urine were collected during the postprandial period and rats were euthanized 6 h after meal intake to collect digestive contents and organs. ResultsOrocaecal digestibility values of amino acids ranged between 96.0 ± 0.2% and 96.6 ± 0.4% for C1-, C2 low Ca2+- and W-matrices, while this value was significantly lower for CW2 matrix (92.4 ± 0.5%). More dietary nitrogen was sequestered in the splanchnic area (intestinal mucosa and liver) as well as in plasma proteins after ingestion of W matrix, especially compared to the C1- and C2 low Ca2+-matrices. Peptidomic analysis showed that more milk protein-derived peptides were identified in the caecum of rats after the ingestion of the matrices containing caseins compared to W matrix. ConclusionWe found that demineralization of micellar caseins did not modify its digestibility and postprandial metabolism. The low digestibility of the modified casein-to-whey ratio matrix may be ascribed to a lower accessibility of the protein to digestive enzymes due to changes in the protein structure, while the higher nitrogen splanchnic retention after ingestion of whey was probably due to the fast assimilation of its protein content. Finally, our results showed that industrial processes that modify the structure and/or composition of milk proteins influence protein digestion and utilization.

Effects of Solid-State Fermentation on the Standardized Ileal Digestibility of Amino Acids and Apparent Metabolizable Energy in Peanut Meal Fed to Broiler Chickens

Peanut meal (PNM) is a byproduct of the peanut oil extraction process, but its application is seriously limited by the presence of anti-nutritional factors, imbalance in amino acid profiles, and susceptibility to mycotoxin contamination. This study was conducted to investigate the effects of solid-state fermentation on the nutritional quality of PNM, as well as the effects of PNM and fermented peanut meal (FPNM) on the ileal digestibility of amino acids and apparent metabolizable energy (AME) of broiler chickens. The results indicated that the fermentation improved the quality of PNM by increasing the crude protein, TCA-soluble protein, and L-lactic acid concentration (p &lt; 0.05), and decreasing the crude fiber, phytic acid, and aflatoxin B1 concentration (p &lt; 0.05). Solid-state fermentation also increased the free amino acids level and improved the balance of hydrolyzed amino acids of PNM. A nitrogen-free diet was used to determine the loss of endogenous amino acid in birds, and the PNM or FPNM as the only protein source to formulate semi-purified diets. The result showed that feeding on FPNM resulted in higher apparent ileal digestibility (AID) and standardized ileal digestibility (SID) values of the essential amino acids of methionine, lysine, leucine, and phenylalanine (p &lt; 0.05). Moreover, the AID and SID values of the non-essential amino acids of FPNM were both higher than those of PNM, except for proline (p &lt; 0.05). The AME was determined by the classic substitution method, and the results showed that fermentation had no effect on the AME value (p &gt; 0.05). In conclusion, solid-state fermentation improved the nutritional value of PNM, and FPNM was a potential ingredient as an alternative protein source for broilers.

Comparison of amino acid digestibility in soybean meal, cottonseed meal, and low-gossypol cottonseed meal between broilers and laying hens.

This study aimed to determine and compare the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of amino acids (AA) in soybean meal (SBM), cottonseed meal (CSM), and low-gossypol cottonseed meal (LCSM) fed to broiler chickens and laying hens. Three semi-purified diets containing the identical crude protein concentration at 20% were formulated to contain SBM, CSM, or LCSM as the sole source of N. A N-free diet was also formulated to estimate the basal ileal endogenous losses of AA for broilers and hens. A total of 300 male Ross 308 chicks at one-day-old and 144 Hy-Line Brown laying hens at 30-week-old with initial egg production rate of 88.3 ±1.0% were randomly allocated into 1 of 4 dietary treatments, respectively. CSM and LCSM showed more Arg and Cys+Met while less Lys, Ile, Leu and Thr relative to SBM. Significant interactions existed between species and experimental diets for AID (except for Arg, Asp, Glu, Gly and Pro) and SID (except for Arg, His, and Phe) of most AA. Most AA in diets showed higher AID (except for Lys) and SID (except for Lys, Met, and Ser) in broilers relative to laying hens. The AID and SID of all AA were significantly different between the three diets. In broilers, the AID and SID of most indispensable AA except for Arg in SBM and LCSM was higher than CSM. In laying hens, the AID and SID of most indispensable AA except for Arg, Met+Cys, and Phe in SBM was higher than CSM and LCSM. The accurate determination of AID and SID of AA in CSM and LCSM for broilers and layers benefits the application of CSM and LCSM in chicken diets. The cottonseed by-products CSM or LCSM showed the species-specific AA digestibility values for broilers and layers.

PSXI-10 Macronutrient and Protein Quality Evaluation of Novel Mammalian Proteins for Canine and Feline Nutrition

Abstract The use of novel protein sources has become a popular human food trend and with the continued humanization of pets, these trends have been followed in the petfood industry. There is limited data regarding the macronutrient composition and overall quality of novel mammalian proteins. In this study, beef, yak, camel, kangaroo, and wild boar were analyzed for chemical composition, amino acid (AA) digestibility, and calculation of digestible indispensable amino acid scores (DIAAS-like) by application of the precision fed cecectomized rooster assay. Dry matter values were &amp;gt;90% and crude protein was greatest in yak meat (95%). Yak meat also contained the least amount of total fat at 11% whereas the greatest amount was found in beef at 57%. The standardized AA digestibility values were determined to be highly digestible as all values were &amp;gt;81%. The reference proteins used for DIAAS-like calculations were based on the Association of American Feed Control officials (AAFCO) nutrient profile and National Research Council (NRC) recommended allowances for adult dogs and cats at maintenance. The DIAAS-like values were &amp;gt;100% for yak and camel meat and were determined to be high quality for dogs. In cats, all proteins received DIAAS-like scores &amp;gt;100% except for wild boar. Tryptophan and methionine were most often the first-limiting acids for both dogs and cats.

PSXI-8 Evaluation of Nutrient Composition and Protein Quality Using the Precision fed Cecectomized Rooster Assay of Novel Avian Protein Sources for pet Nutrition

Abstract Alternative protein sources are being incorporated in companion animal diets as a response to the market demand for high quality products. Chicken is a commonly used protein in pet food and was used as a comparison for emerging alternatives goose, quail, duck, and emu which have been evaluated in the current study. All protein sources were analyzed for chemical composition, and amino acid (AA) standardized digestibility and calculation of digestible indispensable amino acid scores (DIAAS-like) were determined by using the precision fed cecectomized rooster assay. Dry matter values ranged from 95% to 98% and were similar for all proteins. Crude protein was least for goose meat and greatest in emu meat (42% and 95%, respectively). Emu meat produced the least fat content while quail produced the most (4.7% and 42%, respectively). Standardized AA digestibility values for the novel proteins were above 60% for indispensable AA. The DIAAS-like calculation applied reference proteins based on Association of American Feed Control officials (AAFCO) recommended nutrient profile and National Research Council (NRC) recommended allowances for adult dogs and cats at maintenance. The DIAAS-like values for cats for AAFCO and NRC were &amp;gt;100%. Tryptophan was identified to be the first-limiting AA in every protein source except for goose meat where methionine was first-limiting using NRC recommended values for adult dogs.

Comparison of True Ileal Amino Acid Digestibility between Adult Humans and Growing Pigs

It is not feasible to determine the true ileal amino acid (AA) digestibility of protein sources in humans on a routine basis, and the growing pig has been recommended as an animal model for this purpose but requires further validation. To determine and compare true ileal AA digestibility between adult human ileostomates and growing cannulated pigs for a range of food proteins. Seven protein sources (black beans, bread, collagen, pigeon peas, wheat bran, whey protein isolate, and zein) that spanned the range of digestibilities typically seen in foods were evaluated. Six female growing pigs received each of the protein sources, as well as a protein-free diet, and digesta were collected via ileal T-cannula. Adult human ileostomates consumed the same protein sources (5-8 ileostomates, depending on the protein source), as well as a protein-free diet, and digesta were collected. Titanium dioxide and celite were included in the diets as indigestible markers. True ileal AA digestibility coefficients were determined. There was a significant effect of protein source (P≤0.001) for all AAs. The effect of species was not significant (P>0.05) except for total lysine (but not for available lysine). When analyzed within diets, the statistically significant species effect for true lysine digestibility was found for black beans only. Pig and human digestibility values were generally highly and significantly (P≤0.05) correlated. A linear regression equation derived for true ileal AA digestibility (given as coefficients) determined in the human and pig for the overall mean of all AAs was (y=human, x=pig) y=1.00x - 0.010, with the slope not statistically significant (P>0.05) from unity and the intercept not different (P>0.05) from zero. True ileal AA digestibility values determined in the growing pig can be directly used for predicting digestibility in adult humans.

The Complementarity of Amino Acids in Cooked Pulse/Cereal Blends and Effects on DIAAS.

The aim was to study the complementary effect between cereals and pulses on protein quality. The values for the digestible indispensable amino acid score (DIAAS) in cooked cereals and pulses, given alone, and blends of cooked cereals and pulses, were determined. True ileal digestibility (TID) values of amino acids for adult humans were obtained. It is difficult to determine ileal amino acid digestibility in humans directly, and for this reason, the growing pig is often used to obtain such values, as a preferred animal model. Seven growing pigs fitted with a T-cannula at the terminal ileum were allotted to a 7 × 6 incomplete Latin square with seven semi-synthetic diets (cooked mung bean, adzuki bean, millet, adlay, mung bean + millet, adzuki bean + adlay, and an N-free diet) and six 7-day periods. The mean TID values for crude protein differed significantly (p < 0.05), with millet having the highest digestibility (89.4%) and the adzuki bean/adlay mixture having the lowest (79.5%). For lysine, adzuki bean had the highest TID (90%) and millet had the lowest (70%). For the mean of all the amino acids, there was a significant (p < 0.05) effect of diet, with the TID ranging from 72.4% for the adzuki bean/adlay mixture to 89.9% for the adzuki beans. For the older child, adolescent, and adult, the DIAAS (%) was 93 for mung beans, 78 for adzuki beans, 22 for millet, 16 for adlay, and 66 for mung beans + millet, and 51 for adzuki beans + adlay. For mung beans, valine was first-limiting, and the SAA for adzuki beans, while lysine was first-limiting for the other foods. Chinese traditional diets, containing both cereals and pulses, are complementary for most, but not all of the indispensable amino acids.

Black soldier fly larvae in broiler diets improve broiler performance and modulate the immune system.

Non-conventional feed ingredients are receiving more interest in their ability to increase farming efficiency, sustainability and animal performance. The objective of this study was to determine the optimal rate of inclusion level of the full-fat black soldier fly larvae (BSFL) in broiler diets and to evaluate their impact on performance, nutrient digestibility, and the immune system (blood cells and intraepithelial lymphocytes). A total of 400 male day-old Ross 308 broilers were randomly assigned to 5 treatment groups with 8 replicates each. Five inclusion levels of full-fat BSFL were investigated across starter (0, 2.5%, 5%, 7.5% and 10%), grower and finisher diets (0, 5%, 10%, 15% and 20%). All diets were formulated based on digestible amino acid values according to the Aviagen (2016) recommendations. A polynomial regression at different degrees was performed to analyse broiler performance parameters (body weight, body weight gain, feed intake, and feed conversion ratio), nutrient digestibility, and blood cell count. Intraepithelial lymphocyte population data was analysed performing univariate linear regression. During the entire experimental period (from 2 to 42 d), BSFL inclusion levels decreased the feed conversion ratio by 10% in broilers that received 20% BSFL in their diets (P < 0.05). Lymphocytes and white blood cell count decreased linearly by 47.7% and 35.9%, respectively, with up to 20% BSFL inclusion (P < 0.001). A 4-fold decrease in CD3+ T lymphocytes and a 9.7-fold decrease of CD3+CD8+ intestinal cytotoxic T lymphocytes occurred in broilers fed 20% BSFL compared to the control group. These findings suggest that the inclusion of BSFL can improve broiler performance and potentially reduce immune response energy expenditure in birds fed 20% BSFL for 42 d.

True metabolizable energy and amino acid digestibility in black soldier fly larvae meals, cricket meal, and mealworms using a precision-fed rooster assay

Six precision-fed rooster assays were conducted to determine nutrient composition, nitrogen-corrected true metabolizable energy (TMEn) and standardized amino acid digestibility for three black soldier fly larvae meals (BSFL), one partially-defatted BSFL, one cricket meal and two mealworm meals. The TMEn values were determined in three 48-h rooster assays using conventional roosters and the standardized amino acid digestibility values were determined in three 48-h rooster assays using cecectomized roosters. Nutrient analysis (DM basis) of the meals indicated that the CP varied from 45 to 58% among the four BSFL, was 67% for the cricket meal and varied from 51 to 56% for the two mealworms. Crude fat (12–30%), total P (0.7–1.1%), Ca (0.04–3.6%), and neutral detergent fiber (10–36%) also varied among the insect meals. The TMEn values for the three BSFL were generally consistent and averaged 4079 kcal/kg DM. As expected, partially-defatted BSFL contained a lower level of TMEn. The TMEn of the cricket meal was 4223 kcal/kg DM. Due to their low fiber content and high fat content, the TMEn values for the two mealworms were high and in excess of 5000 kcal/kg DM. Amino acid concentrations of the various insect meals ranged from 0.69 to 1.1% for methionine, 0.57 to 0.73% for cystine, 3.3 to 4.5% for lysine, and 1.9 to 2.6% for threonine. Standardized amino acid digestibility values were generally high (most were 85–95%) for the four BSFL and two mealworms. Digestibility values for most amino acids were slightly lower for the cricket meal. Digestibility of cystine and valine were generally lower and more variable than other amino acids in the seven insect meals. The results of this study indicated that nutrient composition varies substantially among different insect meals, but all insect meals contained high levels of TMEn and digestible amino acids compared with feed ingredients commonly used in poultry diets.

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.

Effect of using insects as feed on animals: pet dogs and cats

The ‘buzz’ in society around insects has resulted in the appearance of insect-based pet food products on the market and more products are under development. This contribution aimed to provide background information on pet foods and the sector and to provide an overview of the current state of knowledge regarding naturalness, palatability, nutritional quality, health effects, and sustainability of insects as feed for dogs and cats. In contrast to dogs, natural diets of cats commonly contain insects but contribution to the total biomass is &lt;0.5% in most diets. Cats and dogs can have a different palate when it comes to insects and insect species and inclusion level influence the acceptance of the food. The apparent faecal N digestibility values for insect-based foods were in the range of foods containing conventional protein sources. Based on the indispensable amino acid (IAA) digestibility values reported for black soldier fly larvae (BSFL), housefly larvae (HFL), and yellow mealworms (YMW) in chickens and requirements of growing dogs and growing cats, the first limiting IAA were methionine (BSFL, dogs and cats; YMW, dogs and cats), threonine (BSFL, dogs), and leucine (HFL, dog and cats). More long-term studies are still required to evaluate adequacy and safety of insect-based pet foods in dogs and cats as well as studies that focus on the presence of health-promoting biofunctionalities of insects. Insect proteins have a lower environmental impact than livestock meat proteins, but this is not relevant in the context of pet foods that are largely based on animal co-products with a low environmental impact. Developments in insect rearing will make insect proteins more competitive with conventional sources. For advancing insect applications beyond hypoallergenic pet foods, it will be essential to assure insects as safe and quality ingredients as well as understanding pet owner views and values regarding insect rearing.

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.

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.

Toward standardized amino acid matrices for exogenous phytase and protease in corn–soybean meal–based diets for broilers

A total of 468 male Ross 308 broilers were used in a digestibility study 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 that were supplemented, or not, with either phytase, protease, or a combination of phytase and protease. These treatments generated a total of 12 experimental diets that were arranged in a 3 × 4 design. A nitrogen-free diet was also fed to estimate endogenous AA loss. Apparent and standardized AA digestibility values were assessed on day 28 posthatch. The apparent digestibility of AA in the complete diet was higher (P < 0.05) than expected based on the digestibility of the corn and SBM individually. However, this overestimation was corrected by the adjustment to standardized values. Importantly, addition of protease or the combination of protease and phytase increased (P < 0.05) the digestibility of AA in corn and SBM. Furthermore, these effects were arithmetically coherent with respect to the measured effects of the enzymes in the mixture of corn and SBM, even improving the additivity of AA digestibility values when assessed on an apparent basis. This study demonstrates that the effect of exogenous protease and phytase on AA digestibility in complete diets is predictable based on measurements made in individual ingredients. In addition to improving digestibility values per se, exogenous protease and phytase may enhance precision in least cost formulation systems.

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.