Digestible Indispensable Amino Acid Research Articles

64 Effect of feeding intact protein from soybean meal instead of crystalline amino acids on growth performance, protein synthesis, and immune response of growing pigs

Abstract The objective was to test the hypothesis that feeding intact protein from soybean meal (SBM) instead of crystalline amino acids (AA) does not affect growth performance, protein synthesis, intestinal morphology, or immune response of growing pigs. A control corn-SBM diet was used. Three additional diets were formulated by reducing the inclusion rate of SBM and adding 3, 4, or 5 crystalline AA (i.e., Lys, Met, Thr, Trp, Val) to the diets, which resulted in reducing the protein concentration from 20.0% to 13.4%. All diets were formulated to meet requirements for standardized ileal digestible indispensable AA. A total of 176 pigs [initial body weight (BW) = 32.2 kg; SD = 4.2] were used. On d 1, 16 randomly chosen pigs were euthanized and body nutrient composition was determined. The remaining 160 pigs were allotted to the 4 diets using a randomized complete block design with 4 pigs per pen and 10 replicate pens per diet. Starting BW was the blocking factor. Individual pig BW and feed consumption were recorded. On d 28, one pig per pen was slaughtered and blood, carcass, and viscera were collected and analyzed for N, fat, and energy to calculate deposition in the body. Ileal mucosa, ileum and colon tissue and digesta were analyzed for blood characteristics, cytokines, tissue morphology, ammonia, and gene expression. Contrasts coefficients were used to determine linear and quadratic effects of reducing dietary protein. Results indicated that average daily gain, average daily feed intake, gain to feed ratio, carcass characteristics, and protein, lipid, and energy depositions were not affected by reducing SBM and increasing crystalline AA in diets (Table 1). However, energy efficiency tended to decrease (quadratic, P = 0.083) by reducing dietary protein. Blood urea N was reduced (linear, P < 0.001) as dietary protein was reduced, but blood total protein was not affected by dietary treatment. Cytokines, ileal and jejunal morphologies, and gene abundance of AA transporters in the ileal mucosa were not affected by dietary protein. Ammonia concentrations in ileal digesta increased and then decreased (quadratic, P = 0.043) and colon digesta tended to increase and then decrease (quadratic, P = 0.074) as dietary protein was reduced. Bacteria protein in colon digesta was reduced (linear, P = 0.030) by reducing dietary protein. In conclusion, providing AA from intact protein from SBM or from crystalline AA did not affect growth performance, intestinal morphology, and immune response of pigs. However, SBM in diets can provide energy that may be utilized more efficiently than energy from diets with less SBM and crystalline AA. Further research is suggested to elucidate if SBM improves utilization of other nutrients in diets for pigs.

True Ileal Amino Acid Digestibility and Protein Quality of 15N-Labeled Faba Bean in Healthy Humans

BackgroundThe recommended transition toward more plant-based diets, particularly containing legumes, requires a wider knowledge of plant protein bioavailability. Faba beans are cultivated at different latitudes and are used increasingly in human nutrition. ObjectivesWe aimed to assess the nutritional quality of faba bean protein in healthy volunteers equipped with an intestinal tube to implement the ileal 15N balance method. MethodsNine volunteers completed the study (7 males, 2 females, aged 33 ± 10 y, BMI: 24.7 ± 2.6 kg/m2). They were equipped with a nasoileal tube. After fasting overnight, they ingested a test meal consisting of cooked mash of dehulled faba bean seeds (20 g protein per serving of approximately 250 g) intrinsically labeled with 15N. Samples of ileal contents, plasma, and urine were collected over an 8-h postprandial period. Undigested nitrogen (N) and amino acids (AAs) were determined using isotopic MS, and subsequently, ileal digestibility and digestible indispensable amino acid score (DIAAS) were calculated. The measurement of postprandial deamination allowed calculation of the net postprandial protein utilization (NPPU). ResultsThe ileal N digestibility was 84.1% ± 7.7%. Postprandial deamination represented 19.2% ± 3.6% of ingested N, and the NPPU was 64.7% ± 9.7%. The ileal digestibility of individual AAs varied from 85.1% ± 13.7% for histidine to 94.2% ± 3.6% for glutamine + glutamate. The mean AA digestibility was ∼6 percentage points higher than the digestibility of N, reaching 89.8% ± 5.9%, whereas indispensable AA digestibility was 88.0% ± 7.3%. Histidine and tryptophan were the first limiting AAs [DIAAS = 0.77 (calculated by legume-specific N-to-protein conversion factor 5.4); 0.67 (by default factor 6.25)]. Sulfur AAs were limiting to a lesser extent [DIAA ratio = 0.94 (N × 5.4); 0.81 (N × 6.25)]. ConclusionsProtein ileal digestibility of cooked, dehulled faba beans in humans was moderate (<85%), but that of AAs was close to 90%. Overall protein quality was restricted by the limited histidine and tryptophan content.This trial was registered at clinicaltrials.gov as NCT05047757.

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.

186 Amino Acid Digestibility of Various Protein-Based Ingredients Using the Precision-Fed Cecectomized Rooster Assay

Abstract Given their high protein quality and sustainable production practices, there is growing interest in using single cell-based proteins in pet foods. Because there has been a lack of testing on these proteins, the objective of this experiment was to determine the amino acid (AA) digestibilities of a single cell protein and other protein-based ingredients using the precision-fed cecectomized rooster assay. Test ingredients included: Calysta microbial protein (MP), chicken meal (CM), corn gluten meal (CGM), pea protein (PP), and black soldier fly larvae (BSFL). All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. Thirty cecectomized roosters (n = 6/ingredient) were randomly assigned to test ingredients. After 24 h of feed withdrawal, roosters were tube-fed 15 g of test ingredient and 15 g of corn. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using 5 additional cecectomized roosters. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to AAFCO nutrient profiles, FEDIAF nutritional guidelines, and NRC recommended allowances for adult dogs, adult cats, growing puppies, and growing kittens. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P &amp;lt; 0.05 being significant. All of the reactive lysine:total lysine ratios, an indicator of heat damage, were greater than 0.9 except for CM (0.86). All indispensable AA had digestibilities &amp;gt;85% for MP, with indispensable AA digestibilities being &amp;gt;80% for all ingredients. In general, CGM had the greatest AA digestibilities, while CM had the least AA digestibilities. Two exceptions were the digestibilities of lysine and tryptophan, which were greatest in MP. Lysine digestibility for MP (92.3%) was greater (P &amp;lt; 0.01) than that of all other ingredients. Tryptophan digestibility for MP (97.2%) was greater (P &amp;lt; 0.0001) than that of CM, CGM, and PP. Threonine and valine digestibilities were also greater for MP. Threonine digestibility was greatest for CGM (91.0%) and MP (88.6%), being greater (P &amp;lt; 0.0001) than that of the other ingredients. Valine digestibility was greatest for CGM (93.3%), PP (89.3%), and MP (89.3%), being greater (P &amp;lt; 0.001) than that of CM. DIAAS-like calculations estimated the protein quality of each ingredient, with the limiting AA of each depending on the reference used (NRC; AAFCO; FEDIAF) and life stage (growing; adult) and species (dog; cat) of animal in question. For dogs, limiting AA were most commonly methionine, threonine, and tryptophan. For cats, limiting AA were most commonly lysine and methionine. Further research in dogs and cats is necessary to confirm sufficient palatability and digestibility. However, our data suggest that the MP tested is a high-quality protein source with high AA digestibilities, and may serve as a valuable protein alternative for pet foods.

PSXIII-27 Evaluation of Protein Quality of Select Chicken-Based Protein Sources Using the Precision-Fed Cecectomized Rooster Assay

Abstract The objective of this experiment was to determine and compare the standardized amino acid (AA) digestibility of chicken-based protein sources using the precision-fed cecectomized rooster assay. Four ingredients were tested: spray-dried chicken protein hydrolysate (CPH), spray-dried chicken meat (CC), spray-dried chicken broth (CB), and chicken meal (CM). All animal care procedures were approved by the University of Illinois Institutional Animal Care and Use Committee before experimentation. Sixteen cecectomized roosters (4 roosters per substrate) were randomly assigned to the four test substrates. After 24 h of feed withdrawal, roosters were tube-fed 12 g of test substrates and 12 g of corn. Following crop intubation, excreta (urine and feces) were collected for 48 h. Endogenous corrections for AA were made using 5 additional cecectomized roosters. All data were analyzed using the Mixed Models procedure of SAS version 9.4. Generally, CC had the greatest (P &amp;lt; 0.05) standardized digestibility for AA, followed by CPH. Methionine, phenylalanine, and valine had greater (P &amp;lt; 0.05) digestibility in CC and CPH compared with CB and CM. Digestibility of isoleucine and leucine were greater (P &amp;lt; 0.05) in roosters fed CC, followed by CPH, CM, and CB. Greater digestibility (P &amp;lt; 0.05) of lysine was observed in roosters fed CC and CPH, followed by CM and CB. Histidine and threonine had the least digestibility (P &amp;lt; 0.05) in CB compared with all other ingredients. In contrast, digestibility of tryptophan was greatest (P &amp;lt; 0.05) in CC, followed by CPH and CB, while CM had similar (P &amp;gt; 0.05) digestibility to CC and CPH. Amino acid digestibility for most indispensable AA was above 80% for all ingredients, except for histidine, lysine, and threonine, which were exceptions only for CB (68%, 73%, and 74%, respectively). For selected dispensable AA, amino acid digestibility was above 60% for all ingredients, except for aspartic acid in CB and CM, and serine in CB, which were exceptions (43, 68% and 66%, respectively). In general, the least DIAAS values were observed in roosters fed CB, followed by CPH, CM, and greatest in CC. Overall, CC and CPH have comparable indispensable AA digestibility, and tryptophan or phenyl alanine+tyrosine were, generally, the first limiting AA.

Amino acid supplementation during the adaptation period did not affect the standardized ileal digestibility of amino acids in corn and soybean meal fed to pigs.

The objective was to determine the influence of amino acid (AA) supplementation during the adaptation period on the ileal digestibility of crude protein and AA in corn and soybean meal (SBM) fed to pigs. Six barrows with an initial body weight of 30.9±2.6 kg fitted with a T-cannula at the distal ileum were assigned to a 6×6 Latin square design with 6 dietary treatments and 6 periods. Two experimental diets contained corn or SBM as the sole AA source and an N-free diet was additionally prepared. For AA supplementation groups, an AA mixture consisted of Gly, Lys, Met, Thr, Trp, Ile, Val, His, and Phe was added to the corn diet and the N-free diet at the expense of cornstarch, and an AA mixture of Lys, Met, and Thr was added to the SBM diet. All diets contained 0.5% of chromic oxide. The 6 experimental diets were fed to the pigs for four and half days, and the 3 diets containing an AA mixture were switched to the respective diets without AA mixture during the following two and half days. Ileal digesta were collected on days 6 and 7. The addition of an AA mixture during the adaptation period increased apparent ileal digestibility of Arg and Trp in corn (p<0.05) but did not affect that in SBM. The addition of an AA mixture during the adaptation period increased apparent ileal digestibility of Pro and Gly regardless of feed ingredient (p<0.05) but did not affect that of other AA. All AA except Pro in corn and SBM were unaffected by the addition of the AA mixture during the adaptation period. The addition of amino acids to a low-protein diet during the adaptation period does not affect the standardized ileal digestibility of indispensable amino acids in pigs.

Are insects a good source of protein for humans?

When insects are introduced as a novel protein source in human diets, we need to understand the protein quality to compare their nutritional value with other foods. Protein quality assessment methods are based on evaluation of the ability of the protein to meet the amino acid (AA) requirements of the human body. Most available data comes from animal models, either in rats or pigs. The limited available data supports edible insects as a high-quality protein source for human consumption. The farmed insect species considered relevant as an alternative protein source are generally of good quality, and the protein quality of the vast diversity of insect species harvested from the wild across continents are likely to be sources of good quality, though this remains to be assessed. For methodological considerations, the recommended DIAAS (digestible indispensable AA score) method relies on accurately determining the total protein content. When determining total protein based on total nitrogen (N), using the standard conversion factor of 6.25 which disregards the non-protein N in insects, the protein quality is underestimated in comparison with other animal-source foods, such as meat and dairy.

The Systemic Availability of Indispensable Amino Acids from Orally Ingested Algal and Legume Protein in Young Children at Risk of Environmental Enteric Dysfunction

BackgroundThe digestion and absorption of ingested protein may be reduced in children with environmental enteric dysfunction (EED), reducing systemic amino acid availability for protein synthesis with resultant growth faltering. This has not been directly measured in children with EED and associated growth faltering. ObjectivesTo evaluate the systemic availability of algal (spirulina) and legume (mung bean) indispensable amino acids (IAAs) in children with EED. MethodsIndian children (18–24 mo) from urban slums were assigned to EED (n = 24) or no-EED (control, n = 17) groups based on the lactulose rhamnose test, where the lactulose rhamnose ratio cutoff for diagnosing EED (≥0.068) was the mean + 2SD of its distribution in healthy, age-, and sex-matched children of high socioeconomic status. Fecal biomarkers of EED were also measured. Systemic IAA availability was calculated from the plasma: meal IAA enrichment ratio for each protein. True ileal mung bean IAA digestibility was measured by the dual isotope tracer method using spirulina protein as reference. Co-administration of free 13C6-phenylalanine allowed for estimating true ileal phenylalanine digestibility of both proteins, and a phenylalanine absorption index. ResultsThere was no significant difference (independent t-test) in the systemic IAA availability from spirulina or mung bean protein between EED and no-EED groups. There was no between-group difference in true ileal phenylalanine digestibility and its absorption index, or in mung bean IAA digestibility. ConclusionsThe systemic IAA availability of algal and legume protein, or the latter’s IAA/phenylalanine digestibility, is not significantly reduced in children with EED and does not correlate with linear growth.This study was registered in Clinical Trials Registry of India (CTRI) with registration number: CTRI/2017/02/007921.

Determination of standardized ileal digestibility of crude protein and amino acids and digestible indispensable amino acid score of faba beans, lentils, and yellow peas fed to growing pigs

The objective of this study was to determine the standardized ileal digestibility (SID) of protein and amino acids (AA) and calculate the digestible indispensable AA score (DIAAS) of three varieties of Canadian grown pulses (faba bean, lentil, and yellow pea). Three steam-pelleted (80 °C) diets (faba/lentil/pea; 40% inclusion) and a nitrogen-free diet were fed to eight cannulated growing pigs in a 4 × 4 replicated Latin square design. The SID values were used to calculate DIAAS. There were no differences in SID of protein and AA when all diets were compared ( P &gt; 0.05). The SID of methionine was 95% for faba beans, 96% for lentils, and 96% for peas. The SID of lysine was 93% for faba beans, 92% for lentils, and 90% for peas. Tryptophan had the lowest SID across all indispensable AA of all pulses (59% faba, 61% lentil, and 41% pea). All other indispensable AA SID were above 80%. Tryptophan was the limiting indispensable AA for all pulses as determined by DIAAS, with scores of 30 (faba), 57.83 (lentil), and 27.27 (pea). These values will aid in optimal inclusion of steam-pelleted pulses in diets for swine and provide an insight on the protein quality of pulses for humans.

Nutritional profiling and contaminant levels of five underutilized fish species in Norway.

Exploring and making use of underutilized marine resources can be a sustainable approach to achieve future demands of fish consumption by the ever-growing population. Five species, namely European plaice (Pleuronectes platessa), European flounder (Platichthys flesus), lemon sole (Microstomus kitt), megrim (Lepidorhombus whiffiagonis), and thornback ray (Raja clavate), often captured as by-catch in Norway, were characterized for their nutritional value and potential accumulation of hazardous components. The proximate composition, protein profile, fatty acid profile as well as essential and toxic trace elements and polychlorinated biphenyls (PCBs) were analyzed. Digestible indispensable amino acid (DIAA) ratios and scores (DIAAS) and contributions of omega-3 fatty acids to the diet were calculated. Analysis on proximate composition revealed low fat contents of 0.74 to 1.25% and sufficient protein contents between 16.9 and 24% in the five species. Results of DIAA indicate a profitable distribution, with contributions exceeding the daily intake recommendations for an adult person related to a 200 g fillet. Moreover, findings on the distribution of eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) showed remarkable results, considering that the investigated species are lean fish. All five investigated fish exceed the recommended average daily intake level (AI) of EPA + DHA in a 200 g portion. As to toxic trace elements and PCBs, no significantly elevated levels were found considering a portion size of 200 g. Consequently, the nutritional quality of the investigated fish can be regarded as profitable with overall low potential health risks.

Ileal Digestibility of Nitrogen and Amino Acids in Human Milk and an Infant Formula as Determined in Neonatal Minipiglets

BackgroundInfant formula (IF) has to provide at least the same amount of amino acids (AAs) as human milk (HM). AA digestibility in HM and IF was not studied extensively, with no data available for tryptophan digestibility. ObjectivesThe present study aimed to measure the true ileal digestibility (TID) of total nitrogen and AAs in HM and IF to estimate AA bioavailability using Yucatan mini-piglets as an infant model. MethodsTwenty-four 19-day-old piglets (males and females) received either HM or IF for 6 days or a protein-free diet for 3 days, with cobalt-EDTA as an indigestible marker. Diets were fed hourly over 6 h before euthanasia and digesta collection. Total N, AA, and marker contents in diets and digesta were measured to determine the TID. Unidimensional statistical analyses were conducted. ResultsDietary N content was not different between HM and IF, while true protein was lower in HM (−4 g/L) due to a 7-fold higher non-protein N content in HM. The TID of total N was lower (P < 0.001) for HM (91.3 ± 1.24%) than for IF (98.0 ± 0.810%), while the TID of amino acid nitrogen (AAN) was not different (average of 97.4 ± 0.655%, P = 0.272). HM and IF had similar (P > 0.05) TID for most of the AAs including tryptophan (96.7 ± 0.950%, P = 0.079), except for some AAs (lysine, phenylalanine, threonine, valine, alanine, proline, and serine), with small significant difference (P < 0.05). The first limiting AA was the aromatic AAs, and the digestible indispensable AA score (DIAAS) was higher for HM (DIAASHM = 101) than for IF (DIAASIF = 83). ConclusionHM, compared to IF, had a lower TID for total N only, whereas the TID of AAN and most AAs, including Trp, was high and similar. A larger proportion of non-protein N is transferred to the microbiota with HM, which is of physiological relevance, although this fraction is poorly considered for IF manufacturing.

Digestive and metabolic bioavailability in healthy humans of 15N-labeled rapeseed and flaxseed protein incorporated in biscuits

BackgroundIn the search to diversify protein sources for humans, oilseeds are good candidates due to the high protein content of their coproducts after oil extraction. Among them, rapeseed presents a well-balanced amino acid (AA) profile. Flaxseed is an emerging source but the nutritional value of its protein is not yet documented. ObjectivesThis study aimed to determine the nitrogen (N) and AA bioavailability of these protein sources. MethodsNineteen healthy volunteers were intubated with a naso-ileal tube. They ingested 156 g biscuits containing intrinsically labeled 15N rapeseed (n = 10) or flaxseed (n = 9) protein over a 4-h period. Ileal digesta, blood, and urine were sampled over 8 h after the first meal ingestion. N and 15N enrichment and AAs were measured to determine digestive and deamination losses. Ileal digestibility, the digestible indispensable AA score (DIAAS) and net postprandial protein utilization (NPPU) were calculated. ResultsReal ileal digestibility was 80.7 ± 6.5% for rapeseed protein and 92.2 ± 2.0% for flaxseed protein (P = 0.0002). Mean indispensable AA (IAA) digestibility reached 84.1 ± 6.9% and 93.3 ± 6.7% for rapeseed and flaxseed, respectively, lysine being the lowest digestible IAA for both sources. Despite moderate digestibility, the DIAAS was 1.1 for rapeseed but only 0.6 for flaxseed due to lysine insufficiency. Deamination losses accounted for 20.0 ± 6.5% of dietary N for flaxseed and 11.0 ± 2.8% for rapeseed (P = 0.002). The NPPU did not differ between the protein sources, with 71.3 ± 6.5% for flaxseed and 69.7 ± 7.6% for rapeseed. ConclusionsDespite good digestibility, flaxseed protein cooked in biscuits was penalized by both lysine insufficiency and poor lysine digestibility that decreased its DIAAS and increased deamination. By contrast, rapeseed was moderately digestible but presented no limiting IAA, resulting in an excellent DIAAS and low deamination.This study was registered at clinicaltrials.gov as NCT04024605.

Comparing the standardized amino acid digestibility of an alternative protein source with commercially available protein-based ingredients using the precision-fed cecectomized rooster assay.

Using single-cell-based proteins in pet foods is of interest, but little testing has been done. Therefore, our objective was to determine the amino acid (AA) digestibilities, assess protein quality of a novel microbial protein (MP) (FeedKind), and compare it with other protein-based ingredients using the precision-fed cecectomized rooster assay. Test ingredients included: MP, chicken meal (CM), corn gluten meal (CGM), pea protein (PP), and black soldier fly larvae. Thirty cecectomized roosters (n = 6/ingredient) were randomly assigned to test ingredients. After 24 h of feed withdrawal, roosters were tube-fed 15 g test ingredient and 15 g corn, and then excreta were collected for 48 h. Endogenous AA corrections were made using additional roosters. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to Association of American Feed Control Officials (AAFCO), The European Pet Food Industry Federation, and National Research Council reference values for growing and adult dogs and cats. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P ≤ 0.05 being significant. All reactive lysine:total lysine ratios, an indicator of heat damage, were higher than 0.9, except for CM (0.86). Digestibility of indispensable and dispensable AA were >85% and >80% for MP, respectively, with indispensable AA digestibilities being >80% for all other ingredients. In general, CGM had the highest, while CM had the lowest AA digestibilities. Two exceptions were lysine and tryptophan. Lysine digestibility for MP was higher than that of all other ingredients, while tryptophan digestibility for MP was higher than that of CM, CGM, and PP. Threonine digestibility was highest for CGM and MP. Valine digestibility was highest for CGM, PP, and MP. DIAAS-like calculations identified limiting AA of each ingredient and depended on the reference used and life stage and species of animal. Using AAFCO guidelines, all DIAAS-like values for MP were >100 suggesting that it could be used as the sole source of protein in adult dog and cat diets; only methionine had DIAAS-like values <100 for growing kittens. For dogs, limiting AA was most commonly methionine, threonine, and tryptophan in the other protein sources. For cats, limiting AA was most commonly lysine and methionine. Lysine was severely limited in CGM across all life stages considered. Further research in dogs and cats is necessary, but our data suggest that the MP tested has high AA digestibilities and is a high-quality protein source that may be useful in pet foods.

Amino acid digestibility and nitrogen-corrected true metabolizable energy of mildly cooked human-grade vegan dog foods using the precision-fed cecectomized and conventional rooster assays.

The pet food market is constantly changing and adapting to meet the needs and desires of pets and their owners. One trend that has been growing in popularity lately is the feeding of fresh, human-grade foods. Human-grade pet foods contain ingredients that have all been stored, handled, processed, and transported in a manner that complies with regulations set for human food production. While most human-grade pet foods are based on animal-derived ingredients, vegan options also exist. To our knowledge, no in vivo studies have been conducted to analyze the performance of human-grade vegan diets. Therefore, the objective of this study was to investigate the amino acid (AA) digestibility and nitrogen-corrected true metabolizable energy (TME n ) of mildly cooked human-grade vegan dog foods using precision-fed cecectomized rooster and conventional rooster assays. Three commercial dog foods were tested. Two were mildly cooked human-grade vegan dog diets (Bramble Cowbell diet (BC); Bramble roost diet (BR)), while the third was a chicken-based extruded dog diet (chicken and brown rice recipe diet (CT)). Prior to the rooster assays, both mildly cooked diets were lyophilized, and then all three diets were ground. Diets were fed to cecectomized roosters to determine AA digestibility, while conventional roosters were used to determine TME n . All data were analyzed using the mixed models procedure of SAS (version 9.4). The majority of indispensable and dispensable AA across all diets had digestibilities higher than 80%, with a few exceptions (BC: histidine, lysine, threonine, and valine; BR: histidine). The only difference in indispensable AA digestibility among diets was observed with tryptophan, with its digestibility being higher (P = 0.0163) in CT than in BC. TME n values were higher (P = 0.006) in BC and BR (4.55 and 4.66 kcal/g dry matter, respectively) than that in CT (3.99 kcal/g dry matter). The TME n /GE was also higher (P = 0.0193) in BR than in CT. Metabolizable energy (ME) estimates using Atwater factors accurately estimated the energy content of CT, but modified Atwater factors and the predictive equations for ME recommended by the National Research Council underestimated energy content. All calculations underestimated the measured TME n values of BC and BR, with Atwater factors being the closest. Although testing in dogs is required, these data suggest that mildly cooked human-grade vegan dog diets are well-digested. Moreover, TME n data suggest that existing methods and equations underestimate the ME of the mildly cooked human-grade vegan foods tested.

Indispensable Amino Acid Digestibility of Moroccan Fava Bean Using the Dual Isotope Method in Healthy Adults

BackgroundAssessment of protein quality is necessary to satisfy the nutritional needs of populations across the world. In addition to indispensable amino acid (IAAs) composition, protein digestibility is a major component of IAA bioavailability, playing a crucial role in human health and affecting the linear growth of children. ObjectivesThis study aimed to evaluate IAA digestibility of fava beans, a legume widely consumed in Morocco using the dual-tracer method. Methods2H-intrinsically labeled Fava beans supplemented with 12 mg/kg BW of 13C spirulina were given to 5 healthy volunteers (3 men and 2 women), aged 25.8 ± 3.3 y, with a mean BMI of 20.0 kg/m2. The meal was spread in small portions and was given hourly throughout 7 h. Blood was sampled at baseline and hourly from 5 to 8 h after meal ingestion. IAA digestibility was evaluated by gas chromatography—combustion—isotope ratio mass spectrometry using the 2H/13C ratio in plasma IAA. Digestible indispensable amino acid ratios (DIAAR) were calculated using the scoring pattern for people older than 3 y. ResultsFava beans had an adequate level of lysine but were limiting in several IAAs, especially methionine. Under our experimental conditions, the average IAA digestibility of fava bean was 61.1% ± 5.2%. Valine had the highest digestibility (68.9% ± 4.3%) and threonine had the lowest (43.7% ± 8.2%). In consequence, the lowest DIAAR was 67% for threonine and only 47% for sulfur amino acids (SAA). ConclusionsThe present study is the first to determine the digestibility of fava bean amino acids in humans. The mean IAA digestibility was moderate, and consequently, we conclude that fava bean provides a limited amount of several IAAs, especially SAA, but adequately for lysine. Preparation and cooking methods of fava beans should be improved to increase digestibility.This study was registered at ClinicalTrials.gov as NCT04866927.

Partial Replacement of Soybean Meal with Canola Meal or Corn DDGS in Low-Protein Diets Supplemented with Crystalline Amino Acids-Effect on Growth Performance, Whole-Body Composition, and Litter Characteristics.

Simple SummaryDietary protein reduction with amino acid supplementation is a nutritional approach to reducing environmental pollution. Soybean meal is nutritionally superior to alternative protein feedstuffs, such as corn distillers dried grain with solubles (cDDGS) and canola meal (CM), because of its relatively good balance of amino acids. This study investigated the usage of CM or cDDGS compared to SBM in low-protein broiler diets and their effects on growth performance, carcass yield, whole-body composition, and litter characteristics. The results demonstrated that replacing soybean meal with cDDGS or CM negatively affected the performance of the birds, whereas reducing dietary protein reduced the litter surface ammonia, irrespective of protein feedstuff. Therefore, complete replacement of SBM with cDDGS or CM in low-protein diets is not feasible for optimum performance in broiler chickens.A 42-day study was conducted to explore the application of supplemental amino acids (AA) in low-protein diets with soybean meal (SBM), canola meal (CM) or corn distillers dried grain with solubles (cDDGS) as the main protein feedstuffs. The responses of interest were growth performance, carcass yield, whole-body composition, litter ammonia and litter N. On d 0, a total of 540 Cobb 500 (off-sex) male broilers were allocated to 36 floor pens. All the birds received one starter diet that met nutrient requirements during the first 10d. Thereafter, six experimental diets were provided in grower and finisher phases. The diets included a positive control (PC): a corn–SBM diet with adequate protein. The protein level of the negative control (NC) was decreased by 45 g/kg relative to the PC. The next two diets had the same protein levels as the NC but with cDDGS added at 50 or 125 g/kg. The last two diets had the same CP as the NC but with CM added at 50 or 100 g/kg. All the low-protein diets had the same level of standardized ileal digestible indispensable AA according to Cobb 500 recommended level. Gly and Ser were added as sources of non-specific N. The dietary protein reduction in corn–SBM diets at both phases decreased (p < 0.05) weight gain and increased (p < 0.05) feed conversion ratio (FCR). Increasing levels of cDDGS or CM, at a constant CP level, linearly decreased (p < 0.05) the weight gain and feed intake, whereas increasing CM level linearly increased (p < 0.05) FCR in the grower and finisher phases. The eviscerated and carcass yields decreased, whereas the fat yield increased (p < 0.05) with reduced protein in corn–SBM diet. Increasing levels of cDDGS and CM at a constant CP level quadratically decreased (p < 0.05) the eviscerated weight, whereas the fat weight linearly decreased (p < 0.05) with increasing levels of cDDGS and CM. The birds receiving the PC diet had a lower (p < 0.05) lean muscle (%) and a higher fat (%) compared to birds receiving the NC diet at d 21. However, on d42, birds receiving the PC diet had decreased (p < 0.05) bone mineral density, bone mineral content and lean weight compared to those receiving the NC diet. The litter ammonia increased (p < 0.05) with the increasing levels of protein in the SBM diets. In conclusion, 50 g/kg inclusion levels of CM and cDDGS at the same low-protein levels as SBM produced a similar growth response to the NC, whereas higher levels were detrimental. Hence under the conditions of the current experiment, complete replacement of SBM with DDGS or CM in low-protein diets was not feasible.

PSIII-15 Standardized Amino Acid Digestibility and Protein Quality of Mealworm-Based Ingredients Using the Precision-fed Cecectomized Rooster Assay

Abstract Mealworms may serve as an alternative protein source for pet foods because of their high protein content. The amino acid (AA) content and protein quality of mealworm-based ingredients may vary depending on their composition and processing, however, so testing is required. Our objective was to measure the AA composition, AA digestibility, and protein quality of mealworm-based ingredients using the precision-fed cecectomized rooster assay. The University of Illinois Institutional Animal Care and Use Committee approved all animal procedures prior to experimentation. 12 cecectomized roosters (4 roosters/substrate) were randomly assigned to one of three test substrates: 1) whole buffalo mealworm meal (BMW); 2) defatted yellow mealworm meal (YMW); and enzymatically hydrolyzed mealworm powder (HYD). After 24 h of feed withdrawal, roosters were tube-fed test substrates. Following crop intubation, excreta samples were collected for 48 h. Endogenous loss corrections for AA were made by using 5 additional cecectomized roosters. All data were analyzed using SAS version 9.4. All substrates had high AA digestibilities, with all indispensable AA digestibilities being &amp;gt;90% with the exception of histidine (87.9-91.1%) and valine (77.9%-79.7%). AA digestibilities were not different among substrates. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to AAFCO nutrient profiles, FEDIAF nutritional guidelines, and NRC recommended allowances for adult dogs, adult cats, growing puppies, and growing kittens. In general, HYD had the highest and YMW had the lowest DIAAS-like values for most indispensable AA. Methionine (HYD; YMW) and tryptophan (BMW) were the first-limiting AA. Our results demonstrate that mealworm-based ingredients are high-quality protein sources. Further research in dogs and cats is necessary to confirm sufficient palatability and digestibility, but these data suggest that they will be valuable sources of protein for pet foods.

Digestible indispensable amino acid scores of animal and plant ingredients potentially used in dog diet formulation: how this protein quality metric is affected by ingredient characteristics and reference amino acid profile.

The ability of a diet or an ingredient to satisfy the indispensable amino acid (IAA) requirements of an individual is a reflection of protein quality (PQ). The concept of PQ is gaining recognition in the pet food industry as a way to identify candidate ingredients for diet formulation. The objective of this report was to use IAA digestibility data from swine and cecectomized rooster assays to generate digestible IAA scores (defined herein as DIAAS-like values) to predict the PQ of ingredients used in dog diets. However, as PQ equation development relies on a reference IAA profile, which is intended to be based on the physiological requirements of a specific population, we sought to generate DIAAS-like values using IAA requirements established by the National Research Council (NRC) as well as practical IAA recommendations presented by the Association of American Feed Control Officials (AAFCO) and European Pet Food Industry Federation (FEDIAF), to assess how these profiles may affect PQ. In total, 30 animal (75 unique inputs) and 27 plant ingredients (94 unique inputs) satisfied all inclusion criteria to be used in the final data set. Ingredients were initially categorized as animal or plant, and further categorized based on AAFCO Official Common and Usual Names and Definitions of Feed Ingredients to allow for additional, more distinct comparisons to be made. Data were analyzed using PROC GLIMMIX in SAS, with ingredient reference as a random effect, and ingredient category, regulatory body, and life stage as fixed effects. As expected, differences were observed in DIAAS-like values for nearly all ingredients and ingredient categories when determined using NRC, AAFCO, or FEDIAF IAA requirements or recommendations as the reference pattern. Moreover, applying reference patterns based on NRC adult maintenance IAA requirements consistently produced the lowest DIAAS-like values. Ultimately, while future studies assessing PQ should utilize NRC minimal requirements, individual ingredient and ingredient category differences in DIAAS-like values when using AAFCO and FEDIAF recommendations underpin the different regulatory approaches to establishing dietary nutrient recommendations that exist globally and support the need for harmonization of dietary recommendations.

The True Amino Acid Digestibility of 15N-Labelled Sunflower Biscuits Determined with Ileal Balance and Dual Isotope Methods in Healthy Humans

BackgroundSunflower is a promising protein source but data on amino acid (AA) digestibility are lacking in humans. Classically, the determination of AA digestibility requires ileal digesta sampling. The dual isotope method is minimally invasive but has not been compared to the conventional approach. ObjectivesThis study aimed to determine the true ileal digestibility of sunflower AAs in healthy volunteers who ate biscuits containing 15nitrogen (N) protein isolate, in comparison with the dual isotope method. MethodsTwelve healthy volunteers (men and women; 40.4 ± 10.5 years old; BMI, 23.7 ± 2.9 kg/m2) were equipped with a naso-ileal tube. For 4 hours, they consumed 9 repeated meals comprising 15N-sunflower protein biscuits together with 13carbon (C)-AAs, carried either in chocolate (SUN + Ch; n= 7) or apple puree (SUN + P; n= 5). Ileal digesta and blood were sampled throughout 8 hours after ingestion of the first meal. The 15N and 13C AA enrichments were measured in digesta to determine ileal digestibility directly and in plasma to determine lysine and threonine digestibility using the dual isotope method. Differences between methods and between vector groups were analyzed using paired and unpaired t-tests, respectively. ResultsThe ileal digestibility of sunflower indispensable AAs (IAA) was 89% ± 5.3%, with threonine and lysine having the lowest digestibility. In the SUN + Ch meal, IAA digestibility was 3% below that of SUN + P (P < 0.05). The mean free 13C-AA ileal digestibility was 98.1% ± 0.9%. No matter which matrix was used to carry 13C-AAs, plasma 15N and 13C-AA kinetics displayed a 1-hour offset. Digestibility obtained with the dual isotope method (70.4% ± 6.0% for threonine and 75.9% ± 22.3% for lysine) was below the target values. ConclusionsThe ileal digestibility of IAAs from a sunflower isolate incorporated in a biscuit was close to 90% in healthy adults. Under our experimental conditions, the dual isotope method provided lower values than the usual method. Further protocol developments are needed to validate the equivalence between both methods. This trial was registered at http://www.clinicaltrials.gov clinicaltrials.gov as NCT04024605.

A Salute to PVT TIM HiLL: Indispensable Amino Acids and Global Human Health

Students are taught the study mnemonic “PVT TIM HiLL” to memorize the 9 indispensable amino acids (IAA): phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, histidine, leucine, and lysine. The Food and Agriculture Organization (FAO) recommended that IAA be treated as individual nutrients on food labels because “crude protein ” alone does not indicate protein quality. Protein quality—determined by Digestible Indispensable Amino Acid Score (DIAAS)—is calculated for 3 life stages: birth to 6 months, 6 months to 3 years, and 3 years and older. Foods possessing DIAAS greater than 100 are “excellent” protein quality, and those with DIAAS between 75 and 99 are “good,” whereas foods with DIAAS &amp;lt; 75 cannot make a protein claim. Processing, heating, and/or grinding can decrease or improve plant and animal IAA digestibility. For children 6 months to 3 years of age, ground pork, smoked-cooked bacon, cooked pork leg, cured ham, cooked pork loin, salami, beef/pork bologna, beef jerky, and medium and medium rare beef ribeye steaks can be described as “excellent.” A range of research has reported that cooked ground beef can be classified as “good” or “excellent,” whereas the Impossible® (Impossible Foods, Redwood City, CA) and Beyond® (Beyond Meat Inc., El Segundo, CA) meat-alternative burgers and well-done ribeye can be classified as “good ” sources of IAA for young children. For persons aged &amp;gt; 3 years, all meat categories but cooked ground beef can be classified “excellent” sources of IAA. For meat alternatives, Impossible Burger could be classified as “excellent,” but Beyond Burger could only claim to be “good.” Protein quality claims for individual food ingredients can be diminished when the food is consumed with a lower protein quality item such as a wheat flour bun. To provide meals that are adequate in all IAA, the protein quality in each food item must be determined. Mixed meals must be adjusted for protein quality by combining low-quality proteins (present in cereals and grains) with higher-quality proteins (present in foods of animal origin).