Standardized Amino Acid Digestibility Research Articles

PSI-16 Evaluation of protein quality of defatted black soldier fly (Hermetia illucens) larvae meal compared with traditional protein sources for dogs and cats

Abstract There is increased interest in the use of insects, such as black soldier fly (Hermetia illucens) larvae meal (BSFLM), as an alternative protein source in pet foods. However, additional information is needed to determine how BSFL protein quality compares with traditional pet food protein sources. Thus, the objectives of this study were to determine the chemical composition, amino acid digestibility, and protein quality of defatted BSFLM in comparison with whole egg powder (WEP) and chicken meal (CM) using the precision-fed cecectomized rooster assay. Fifteen cecectomized roosters (n = 5 per substrate) were randomly allocated to the test substrates BSFLM, CM, and WEP. After 26 h of feed withdrawal, 20 g of substrates were crop-fed and excreta were collected for 48 h. Digestible indispensable amino acid score (DIAAS)-like values were calculated using the Association of American Feed Control Officials (AAFCO), The European Pet Food Industry Federation (FEDIAF), and National Research Council (NRC) reference values for different life stages of dogs and cats. Data were analyzed using SAS Proc Mixed 9.4 with P ≤ 0.05 significance. On a dry matter basis, CM had the greatest crude protein (70.2%), followed by BSFLM (59.8%), and WEP (51.2%). In general, WEP had greater amino acid digestibility than BSFLM and CM. BSFLM (84%) and CM (84%) had comparable arginine digestibility, but less than WEP (92%). Lysine digestibility was greater for BSFLM (80%) in contrast with CM (74%), but less than WEP (91%). DIAAS-like values were calculated, revealing methionine + cysteine as the first limiting amino acids for growing puppies and adult dogs in BSFLM according to AAFCO, FEDIAF, and NRC, whereas for CM threonine was the first limiting amino acid based on AAFCO, and phenylalanine + tyrosine based on NRC and FEDIAF. NRC identified methionine and cysteine as limiting for all test substrates in adult dogs. Methionine and cysteine were limiting for growing kittens for BSFLM among AAFCO, FEDIAF, and NRC. For CM and WEP, phenylalanine and tyrosine was the first-limiting amino acid by NRC and FEDIAF. For adult cats, phenylalanine and tyrosine were the limiting amino acid for BSFLMand CM according to AAFCO and FEDIAF, with NRC identifying it as limiting across all protein sources. In summary, methionine and cysteine and/or phenylalanine and tyrosine were the primary limiting amino acids among the protein sources evaluated. In general, BSFLM had comparable indispensable standardized amino acid digestibility to CM.

PSIX-4 Standardized amino acid digestibility of defatted black soldier fly larvae meal (BSFLM) in extruded canine diets

Abstract The use of insects, such as black soldier fly (Hermetia illucens) larvae meal (BSFLM), as an alternative protein source for animal feed, including pet food, has gained attention due to their high nutritional value and sustainability attributes. The aims of the study were to determine the chemical composition and amino acid digestibility of canine diets using BSFL to partially or completely replace chicken meal (CM) at 15% or 30% inclusion using the precision-fed cecectomized rooster assay. Fifteen cecectomized roosters (n = 5 per treatment) were randomly assigned to the test diets: Control, 15% BSFLM, and 30% BSFLM. After 26 h of feed withdrawal, 20 g of substrates were crop-fed and excreta were collected for 48 h. Data were analyzed using SAS Proc Mixed 9.4 with P ≤ 0.05 significance. The chemical composition was similar among all 3 dietary treatments. On average, the diets had similar macronutrient compositions: dry matter 92 to 93.7%, organic matter 89%, crude protein (CP) 26.7 to 28.4%, acid hydrolyzed fat 14.6%, total dietary fiber (TDF) 11.5 to 13.3%, and gross energy was 4.9 kcal/g. The slight variations in CP and TDF concentrations were due to the BSFLM. Additionally, all diets had similar concentrations of indispensable and dispensable amino acids. The standardized digestibility for all indispensable amino acids was above 75% for all dietary treatments, except histidine, lysine, and methionine + cysteine for the 30% BSFLM diet. The inclusion of BSFLM at both 15% or 30%, as a partial or full replacement of chicken by-product meal, did not negatively impact the chemical composition or amino acid digestibility of the experimental diets. Overall, this study highlighted the viability of BSFLM as an alternative and sustainable protein source in canine nutrition, indicating that extruded diets formulated with BSFLM as a partial or primary protein source can sustain adult dogs’ nutritional needs similarly to diets formulated with CM.

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 < 0.05) standardized digestibility for AA, followed by CPH. Methionine, phenylalanine, and valine had greater (P < 0.05) digestibility in CC and CPH compared with CB and CM. Digestibility of isoleucine and leucine were greater (P < 0.05) in roosters fed CC, followed by CPH, CM, and CB. Greater digestibility (P < 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 < 0.05) in CB compared with all other ingredients. In contrast, digestibility of tryptophan was greatest (P < 0.05) in CC, followed by CPH and CB, while CM had similar (P > 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.

PSVIII-18 Standardized Amino Acid Digestibility and Nitrogen-Corrected True Metabolizable Energy of Frozen Raw, Freeze-Dried Raw, Fresh, and Extruded Dog Foods Using Cecectomized and Conventional Rooster Assays

Abstract Processing conditions, particularly temperature and duration of heating, impact the digestibility of pet foods. Various alternative commercial pet food formats are now available, but few have been well tested. Therefore, the objective of this study was to determine the amino acid (AA) digestibility and nitrogen-corrected true metabolizable energy (TMEn) of frozen raw, freeze-dried raw, fresh, and extruded dog foods using the precision-fed cecectomized and conventional rooster assays. The diets tested were Chicken and Barley Recipe [extruded diet; Hill’s Science Diet (EXT)], Chicken and White Rice Recipe [fresh diet; Just Food for Dogs (FRSH], Chicken Formula [raw frozen diet; Primal (FRZN)], Chicken and Sorghum Hybrid Freeze-dried Formula [hybrid freeze-dried raw diet; Primal (HFD)], and Chicken Dinner Patties [raw freeze-dried diet; Stella & Chewy (FD)]. Two precision-fed rooster assays utilizing Single Comb White Leghorn roosters (1.5 to 2.5 yr, 2.5 to 3 kg) were conducted. In the first assay, 20 cecectomized roosters (n = 4/treatment) were used to determine AA digestibility. In the second assay, 20 conventional roosters (n = 4/treatment) were used to determine TMEn. In both assays, roosters were crop intubated with 12 g of test diet and 12 g of corn, and then excreta were collected for 48 h. The reactive lysine:total lysine ratios were 0.94, 0.96, 0.93, 0.93, and 0.95 for the EXT, FRSH, FRZN, HFD, and FD diets, respectively. In general, FD had the greatest AA digestibilities and EXT had the least AA digestibilities. Arginine digestibilities were different (P < 0.05) across all diets and in this pattern: FD > FRZN > FRSH > HFD > EXT. Isoleucine digestibilities were different (P < 0.05) across all diets, but with a slightly different pattern: FD > FRZN > FRSH > EXT > HFD. Lysine digestibility was greater (P < 0.05) in FD and FRZN than EXT, with other diets being intermediate. Methionine digestibility was greater (P < 0.05) in FD than FRSH, with other diets being intermediate. Threonine digestibility was greater (P < 0.05) in FD than EXT, with other diets being intermediate. Valine digestibilities were different (P < 0.05) across all diets and in this pattern: FD > FRZN > EXT > FRSH > HFD. Digestibilities of the other essential AA were not different among diets. TMEn was greater (P < 0.05) in FRZN than FD, FRSH, and EXT, greater (P < 0.05) in HFD than FRSH and EXT, and greater (P < 0.05) in FD than EXT. In conclusion, our results support the notion that diet processing impacts AA digestibility, with freeze-dried raw, frozen raw, and fresh diets consistently having greater digestibility coefficients, as well greater TMEn, than the extruded diet. More research in dogs is necessary to test the effects of these diet formats on palatability, digestibility, stool quality, and other physiologically relevant outcomes.

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.

Nutritional evaluation of soybean meals varying in particle size

The objective of this study was to evaluate the effect of varying soybean meal (SBM) particle sizes on nutritional value of the SBM. Seven samples of dehulled solvent-extracted SBM from the same batch were ground to varying mean particles of <386, 466, 809, 1,174, 1,577, 2,026, and 2,321 μm. Two precision-fed rooster assays (crop intubation with 25 g of SBM followed by 48 h total excreta collection) were performed to determine TMEn and standardized amino acid (AA) digestibility. There were no significant differences for TMEn among SBM samples, and there was also no consistent significant effect of particle size on standardized AA digestibility. In addition to the 2 precision-fed rooster assays, a 21 d broiler chick trial was conducted using corn-SBM based diets using 4 diets that differed only in the mean particle size of SBM (466, 809, 1,174, or 1,577 μm), being fed from 2 to 23 d of age. Chicks fed diets containing 809 or 1,174 μm SBM had increased (P < 0.05) weight gain compared with chicks fed the diet containing 466 μm SBM, and chicks fed diets containing 1,174 or 1,577 μm SBM had increased (P < 0.05) feed efficiency compared with chicks fed the diet containing 466 μm SBM. The diet containing 466 μm SBM yielded the highest (P < 0.05) AMEn and total tract P retention. Ileal P digestibility and standardized AA digestibilities did not differ among treatments. Relative gizzard weight (percent of body weight) was increased (P < 0.05) by the 2 largest SBM particle sizes. The results from these 3 experiments showed that increasing SBM particle size may be beneficial to broiler growth performance and may increase gizzard size but had no consistent significant effect on ME, AA digestibility, or P digestibility/retention.

Determination of standardised ileal digestibility of amino acids in high-fibre feedstuffs and additivity of apparent and standardised ileal amino acids digestibility of diets containing mixtures of maize, sorghum, and soybean meal

ABSTRACT 1. Two experiments were conducted to determine the coefficients of standardised ileal amino acid digestibility for selected high-fibre feedstuffs (Expt.1) and to assess the additivity of coefficients of apparent (cAIAAD) and standardised (cSIAAD) ileal amino acid digestibility for diets containing combinations of sorghum, maize and soybean meal. 2. In Expt. 1, broiler chickens (324) were allocated to 54 metabolism cages (nine diets with six replicates). In Expt. 2, broiler chickens (315) were allocated to 63 metabolism cages (seven diets with nine replicates). The diets in Expt. 1 were a nitrogen-free diet plus eight semi-purified diets in which soybean meal (SBM), low-protein SBM (LPSBM), soybean hull, wheat bran, maize bran, rice bran, dried sugarbeet pulp or maize gluten feed were the only sources of protein in the respective diets. In Expt. 2, the seven diets were a nitrogen-free diet, and six semi-purified diets consisting of individual feedstuffs (SBM, maize, or sorghum) or combinations (maize and SBM; sorghum and SBM; or maize, sorghum, and SBM) as the only sources of protein. 3. In both experiments, all the broiler chickens received the same maize-SBM diet formulated to meet nutrient requirements according to the breeder’s recommendations from d 0 to 16. Allocated experimental diets were provided on d 16, and ileal digesta were collected on d 21. 4. In Expt. 1, SBM and LPSBM had greater (P < 0.01) cSIAAD for indispensable and dispensable amino acids than the other feedstuffs. The rice bran had greater (P<0.01) cSIAAD values than wheat bran and maize bran, except for Leu, Cys, and Pro. 5. In Expt. 2, predicted cAIAAD values for maize-SBM and maize-sorghum-SBM were generally lower (P<0.01) than actual values. The actual and predicted cSIAAD values for maize-SBM, sorghum-SBM and maize-sorghum-SBM combinations were not significantly different. 6. It was concluded that the standardised amino acid digestibility of sorghum, when combined with other feedstuffs, was additive and that approximately three-quarters of total amino acids in the assayed high-fibre feedstuffs, except for dried sugarbeet pulp and maize gluten feed, were digestible.

The apparent metabolisable energy and ileal amino digestibility of black soldier fly (Hermetia illucens) larvae meal for broiler chickens

ABSTRACT 1. Two experiments were conducted to determine the apparent metabolisable energy (AME) and standardised amino acid digestibility coefficients (SIDC) of black soldier fly larvae (BSFL) for broiler chickens. 2. The BSFL contained, on a g/kg dry matter basis: crude protein, 486; crude fat, 320; ash, 58.5; neutral detergent fibre, 181; calcium, 6.8 and phosphorus, 9.1. 3. In Experiment 1, an AME assay was performed wherein broilers were fed two experimental diets (a maize-soy basal diet and a test diet containing 250 g/kg BSFL) for 4 d from d 18 posthatch. The AME of BSFL was calculated based on the difference between the AME values of basal and test diets. The AME and nitrogen-corrected AME were determined to be 19.1and 18.0 MJ/kg of dry matter, respectively. 4. In Experiment 2, the ileal amino acid (AA) digestibility of BSFL was determined using 22-d-old broilers by the direct method and the digesta was collected on d 25. The ratios between the AA and titanium in the diet and digesta were used to calculate the apparent digestibility and then standardised using previously published endogenous losses to estimate the SIDC of AA. The SIDC of Lys, Met, Thr, Val and average SIDC of AA in our BSFL sample were 0.85, 0.90, 0.91, 0.87 and 0.84, respectively. 5. The findings showed that the BSFL meal is a good source of available energy and digestible AA, and could be a potential substitute for soybean meal in broiler diets.

Two-Stage Fermented Feather Meal Enhances Growth Performance and Amino Acid Digestibility in Broilers

The study aimed to investigate the dose tolerance of enzymatically degraded feather meal (EFM) in the diet, and the effect of the two-stage fermented feather meal on the growth performance and amino acid digestibility of broilers. In trial 1, 160 one-day-old broilers were randomly assigned into 0, 10, 15, and 20% EFM groups. In trial 2, 160 one-day-old broilers were randomly assigned into control, 10% EFM, Bacillus subtilis var. natto N21 + B. coagulans L12 fermented EFM (BBEFM), and B. subtilis var. natto N21 + Saccharomyces cerevisiae Y10 fermented EFM (BSEFM) groups. Trial 3 involved 32 twenty-one-day-old male broilers randomly assigned into nitrogen-free diet, highly digestible protein, EFM, and BSEFM groups for a 7-day metabolic trial. During all of the feeding periods, increasing the EFM dosage in the diet linearly and quadratically inhibited weight gain (WG), feed intake, and feed conversion ratio (FCR) (p &lt; 0.05), except the FCR at 22–35 days (p &gt; 0.05). Dietary inclusion of more than 15% resulted in a negative impact on growth performance over days 1–35 (p &lt; 0.05). Therefore, the EFM dose tolerance in the broiler diet is 10%. The WG, FCR, and production efficiency factor of the BSEFM group were better than those of the control group in days 1–35 (p &lt; 0.05). The apparent and standardized ideal amino acid digestibility of BSEFM was higher than EFM in trial 3, except for Met, Cys, and Trp (p &lt; 0.05). In conclusion, the EFM dose tolerance for the broiler diet is 10%. Bacillius subtilis var. natto N21 + S. cerevisiae Y10 fermentation can improve the amino acid digestibility of EFM and enhance broiler growth performance.

Standardized amino acid digestibility and nitrogen-corrected true metabolizable energy of frozen and freeze-dried raw dog foods using precision-fed cecectomized and conventional rooster assays.

Commercial raw or minimally-processed diets, often referred to holistically as raw meat-based diets (RMBD) represent a small portion of the pet food market, but the growth of this sector has been significant in recent years. While traditionally, high-moisture, frozen options were the standard format of commercially available raw diets, freeze-dried raw diets have become more prevalent as of late. Despite the increasing popularity of these commercial raw diet formats, there is a dearth of literature describing their nutritional properties, particularly regarding freeze-dried diets. Therefore, the objective of this experiment was to determine and compare the standardized amino acid (AA) digestibilities and nitrogen-corrected true metabolizable energy (TMEn) of raw frozen and freeze-dried dog foods using precision-fed cecectomized and conventional rooster assays. Three formats of frozen or freeze-dried raw diets provided by Primal Pet Foods (Fairfield, CA, USA) were tested: traditional freeze-dried nuggets (T-FDN), hybrid freeze-dried nuggets (H-FDN), and frozen nuggets (FZN). Diets were fed to cecectomized roosters (4 roosters/diet) to determine AA digestibilities, while conventional roosters (4 roosters/diet) were used to determine TMEn. In both cases, after 26 h of feed withdrawal, roosters were tube-fed 12 to 13 g of test diets and 12 to 13 g of corn. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using five additional cecectomized roosters. All data were analyzed using the Mixed Models procedure of SAS version 9.4. There were no significant differences in standardized AA digestibilities among diets, with digestibilities being high for all diets tested. For most of the indispensable AA, digestibilities were greater than or equal to 90% for all diets. Histidine and lysine were the exceptions, with digestibilities ranging from 82% to 87% and 87% to 92%, respectively. Moreover, the reactive lysine:total lysine ratio, a measure of heat damage, ranged from 0.91 to 0.95. TMEn values were higher (P = 0.0127) in T-FDN (6.1 kcal/g) and FZN (5.9 kcal/g) than H-FDN (5.3 kcal/g) and were most similar to those estimated by Atwater factors. In general, all diets tested had high AA digestibilities and had TMEn values that were most similar to Atwater factors.

Standardized amino acid digestibility and protein quality in extruded canine diets containing hydrolyzed protein using a precision-fed rooster assay.

Protein hydrolysate has become a choice of alternative protein source in canine diets as it showed greater digestibility, lower allergenic responses, and various functional properties when compared with intact proteins. The objective of the study was to determine the effect of hydrolyzed protein inclusion on amino acid digestibility and protein quality in extruded canine diets when compared with a traditional protein source for adult dogs. Five treatment diets were formulated to have similar compositions except for the main protein source. The control diet was formulated with chicken meal (CM) as the primary protein source. Test hydrolyzed proteins, chicken liver and heart hydrolysate (CLH) and chicken hydrolysate (CH) were used to partially or completely substitute CM. The diets were: CONd: CM (30%) diet; 5%CLHd: 5% CLH with 25% CM diet; CLHd: CLH (30%) diet; 5%CHd: 5% CH with 25% CM diet; CHd: CH (30%) diet. A precision-fed rooster assay was used to determine standardized amino acid digestibility for the ingredients and diets. In addition, Digestible Indispensable Amino Acid Score (DIAAS)-like values were calculated for the protein ingredients. All protein ingredients had higher than 80% of digestibility for all indispensable amino acids with no difference among sources (P > 0.05). From the DIAAS-like values referencing AAFCO nutrient profile for adult dogs, CLH and CH did not have any limiting amino acid; on the other hand, CM has a lower DIAAS-like value (93.3%) than CLH and CH (P < 0.05) with tryptophan being the first-limiting amino acid. The DIAAS-like values were often lower when the amino acid combinations methionine + cysteine and phenylalanine + tyrosine were included in the calculation. When referencing NRC recommended allowances and minimal requirements, methionine was the first-limiting amino acid for all protein sources. Amino acid digestibility was mostly above 80% and comparable among the treatment diets. Regarding the digestible indispensable amino acid concentrations in the diets, all of them met the AAFCO nutrient profile for adult dogs at maintenance. In conclusion, both protein hydrolysates were highly digestible, high-quality protein sources, and a full substitution from CM to protein hydrolysate could result in greater protein quality, according to the DIAAS-like values of the ingredients, when compared with CM in extruded canine diets.

Standardized amino acid digestibility and nitrogen-corrected true metabolizable energy of frozen raw, freeze-dried raw, fresh, and extruded dog foods using precision-fed cecectomized and conventional rooster assays.

Processing conditions, particularly temperature and duration of heating, impact pet food digestibility. Various commercial pet food formats are now available, but few have been tested thoroughly. The objective of this study was to determine the amino acid (AA) digestibilities and nitrogen-corrected true metabolizable energy (TMEn) values of frozen raw, freeze-dried raw, fresh (mildly cooked), and extruded dog foods using the precision-fed cecectomized and conventional rooster assays. The diets tested were Chicken and Barley Recipe [Hill's Science Diet, extruded diet (EXT)], Chicken and White Rice Recipe [Just Food for Dogs, fresh diet (FRSH)], Chicken Formula [Primal Pet Foods, frozen raw diet (FRZN)], Chicken and Sorghum Hybrid Freeze-dried Formula [Primal Pet Foods, hybrid freeze-dried raw diet (HFD)], and Chicken Dinner Patties [Stella & Chewy's, freeze-dried raw diet (FD)]. Two precision-fed rooster assays utilizing Single Comb White Leghorn roosters were conducted. Cecectomized roosters (n = 4/treatment) and conventional roosters (n = 4/treatment) were used to determine standardized AA digestibilities and TMEn, respectively. All roosters were crop intubated with 12 g of test diet and 12 g of corn, with excreta collected for 48 h. In general, FD had the highest, while EXT had the lowest AA digestibilities; however, all diets performed relatively well and few differences in AA digestibility were detected among the diets. Lysine digestibility was higher (P < 0.05) in FD and FRZN than EXT, with other diets being intermediate. Threonine digestibility was higher (P < 0.05) in FD than EXT, with other diets being intermediate. Digestibilities of the other indispensable AA were not different among diets. The reactive lysine:total lysine ratios were 0.94, 0.96, 0.93, 0.93, and 0.95 for EXT, FRSH, FRZN, HFD, and FD, respectively. TMEn was higher (P < 0.05) in FRZN than FD, FRSH, and EXT, higher (P < 0.05) in HFD than FRSH and EXT, and higher (P < 0.05) in FD than EXT. In conclusion, our results support the notion that AA digestibilities are affected by diet processing, with FD, HFD, FRZN, and FRSH diets having higher AA digestibility coefficients and greater TMEn values, than the EXT diet; however, other factors such as ingredient inclusion and macronutrient composition may also have affected these results. More research in dogs is necessary to test the effects of format on diet palatability, digestibility, stool quality, and other physiologically relevant outcomes.

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.

Nutrient profile, amino acid digestibility, true metabolizable energy, and indispensable amino acid scoring of whole hemp seeds for use in canine and feline diets.

The use of various hemp-derived products has been rapidly growing in the human nutrition industry and has sparked great interest in using these ingredients for companion animals as well. Thorough research is needed to determine the ingredient and safety standards required for AAFCO approval of hemp ingredients. In order to be effectively incorporated into pet food products, we must determine the nutrient content, quality, and utility of these ingredients in pet species. The objective of this study was to evaluate the nutrient composition of seeds from four different varieties of hemp, NWG 452, NWG 331, NWG 2730, X-59, and determine protein quality and true metabolizable energy using a cecectomized rooster model. The seeds were similar in macronutrient composition, with small variations in acid hydrolyzed fat, crude protein, total dietary fiber and gross energy content, as well as amino acid and long-chain fatty acid profiles. All essential amino acids were present in concentrations that exceeded the NRC (2006) recommended allowances for adult dogs and cats at maintenance with the exception of tryptophan. The long-chain fatty acid profile presented a favorable ratio of omega-6 to omega-3 fatty acids of close to 3.5:1. The results of the cecectomized rooster assay indicated no significant difference in the standardized amino acid digestibility of the indispensable amino acids among the seed varieties (P > 0.05). A significant difference in the true metabolizable energy corrected for nitrogen was observed among the seeds (P < 0.05), following the pattern of higher acid hydrolyzed fat and lower total dietary fiber content resulting in higher metabolizable energy. An adapted calculation of digestible indispensable amino acid score was made to determine protein quality of the hemp seeds using AAFCO nutrient profiles and NRC recommended allowances for adult dogs and cats at maintenance as reference points. The resulting scores determined tryptophan to be the first limiting amino acid and indicate that hemp seeds alone do not meet all the amino acid requirements for adult dogs and cats at maintenance, and would need a complimentary protein source for practical use in companion animal diets. The data from this study suggest that hemp seeds may provide a beneficial source of fat, protein, and dietary fiber, with consideration to differences in nutrient profile among seed varieties. However, further investigation in vivo is needed to determine the safety and efficacy of utilizing hemp in the diets of both canines and felines.

Standardized amino acid digestibility and true metabolizable energy for several increased protein ethanol co-products produced using back-end fractionation systems

Precision-fed rooster trials were conducted to evaluate standardized AA digestibility and TMEn of the increased protein ethanol co-products corn fermented protein (CFP), high protein-distillers dried grains with solubles (HP-DDGS), and reduced fiber high protein-DDGS (RFHP-DDGS) produced using post-fermentation back-end fractionation systems. The TMEn was determined using conventional adult Leghorn roosters, while cecectomized roosters were used to determine standardized AA digestibility. Three to 6 roosters were fasted per treatment for 26 h prior to crop intubation with 27 g of sample and excreta were collected for 48 h post-feeding. Statistical analyses were conducted using a one-way ANOVA for a completely randomized design. Eight samples of CFP were found to contain a mean of 56% CP (DM basis) compared with a mean of 32% for conventional DDGS. The mean TMEn of CFP (3,556 kcal/kg) was greater (P < 0.05) than conventional DDGS1 and 2 (2,767 kcal/kg DM); mean standardized AA digestibility for CFP was similar to conventional DDGS and ranged from 88 to 94%. The mean digestible Lys, Met+Cys, and Thr concentrations for conventional DDGS were 0.79, 1.12, and 0.94%, respectively, whereas those for CFP were 1.74, 2.06, and 1.88%, respectively (DM basis). Two samples of HP-DDGS contained a mean of 51% CP (DM basis), a mean TMEn of 3,325 kcal/kg DM, a mean standardized AA digestibility of 90%, and mean concentrations of digestible Lys, Met+Cys, and Thr, which were 1.53, 1.77, and 1.60%, respectively (DM basis). The mean CP content of 2 RFHP-DDGS was 48% and the mean TMEn was 3,711 kcal/kg DM, which was greater (P < 0.05) than conventional DDGS3 and 4 (2,920 kcal/kg DM). Mean standardized AA digestibility of RFHP-DDGS was 90% and mean digestible Lys, Met+Cys, and Thr concentrations increased from 0.82, 1.01, and 0.95% for conventional DDGS, respectively, to 1.00, 1.59, and 1.44% for RFHP-DDGS, respectively (DM basis). Results indicate these high protein corn ethanol co-products have increased nutritional value for poultry compared with conventional DDGS.

104 Standardized Amino Acid Digestibility of Three Formats of Freeze-Dried dog Foods Using the Precision-fed Cecectomized Rooster Assay

Abstract Freeze-dried pet foods represent a small segment of the pet food market, but its growth has been significant in recent years. Despite their increasing popularity, freeze-dried diets have not been well tested. Therefore, the objective of this experiment was to determine and compare the standardized amino acid (AA) digestibilities of freeze-dried dog foods using the precision-fed cecectomized rooster assay. Three formats of freeze-dried diets provided by Primal Pet Foods (Fairfield, CA) were tested: traditional freeze-dried nuggets (FDN), low-temperature freeze-dried nuggets (LTN), and a hybrid freeze-dried nugget (HN). All animal care procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. Twelve cecectomized roosters (4 roosters per substrate) were randomly assigned to the three test substrates. After 24h of feed withdrawal, roosters were tube-fed 12-13g of test substrates and 12-13g of corn. Following crop intubation, excreta (urine and feces) were collected for 48h. 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. There were no significant differences in standardized AA digestibilities among diets, with digestibilities being high for all tested. For most of the indispensable AA, digestibilities were greater than 90% for all diets (arginine: 94.1%-95.6%; isoleucine: 91.2%-93.1%; leucine: 92.4%-95.3%; methionine: 92.8%-94.9%; phenylalanine: 90.8%-93.6%; tryptophan: 96.2%-98.6%; valine: 90.2%-92.9%). Histidine, lysine, and threonine were the exceptions, with digestibilities ranging from 81.7%-86.6%, 86.7%-91.7%, and 89.6%-91.7%, respectively. Moreover, the reactive:total lysine ratio, a measure of heat damage, ranged from 0.91 to 0.95. In general, the low-temperature nugget had thegreatest numerical AA digestibilities, likely due to reduced heat damage, but all diets performed very well.

Comparison of amino acid digestibility and its additivity determined with slaughter or cecectomy method for yellow-feather chicken

The objective of this experiment was to compare the slaughter and cecectomy methods to determine amino acid (AA) digestibility of corn and soybean meal and their additivity in a corn-soybean meal diet. A completely randomized design was adopted to determine endogenous AA losses (EAAL) and AA digestibility in each of corn, soybean meal, and a corn-soybean meal diet using either slaughter or cecectomy methods. Each treatment contained 6 replicates with 3 chickens per replicate. The endogenous loss (EL) of histidine and glycine was lower and the EL of methionine and phenylalanine was greater when determined by slaughter vs. cecectomy (P < 0.05). The EL of arginine, isoleucine, leucine, lysine, methionine, phenylalanine, valine, alanine, aspartic acid, glutamic acid, and serine determined by slaughter were 1.2 to 3.2 times of those from cecectomy. The standard error (SE) of EL of 14 AA (excluding histidine and glycine) obtained by slaughter method was 2.1 to 9.6 times of those by cecectomy method. The apparent and standardized digestibility was not affected by methods for most AA except apparent digestibility of methionine, phenylalanine and glycine, and standardized digestibility of glycine in corn. The apparent and standardized digestibility of most AA except apparent digestibility of glycine and standardized digestibility of lysine, cysteine and glycine were less for slaughter versus cecectomy methods in soybean meal (P < 0.05). Using slaughter method resulted in reduced apparent digestibility of 15 AA (except glycine) and reduced standardized digestibility of 7 AA (arginine, isoleucine, leucine, valine, aspartic acid, glutamic acid, and proline) relative to cecectomy method (P < 0.05), but the standardized digestibility of glycine was greater when determined by slaughter vs. cecectomy methods in corn-soybean meal diet (P < 0.05). The mean value of SE of 16 AA digestibility in slaughter method was 2.9 times of that by cecectomy method. The apparent digestibility of 2 and 9 of 16 AA and the standardized digestibility of 15 and 7 of 16 AA were additive when using slaughter and cecectomy determinations, respectively. In conclusion, compared to the slaughter method, cecectomy method had less SE and EAAL but greater apparent digestibility of methionine and phenylalanine in corn, and the apparent digestibility of 15 AA (except glycine) in soybean meal and corn-soybean meal diet. Additivity in apparent and standardized AA digestibility was more inconsistent when determined with slaughter vs. cecectomy methods. These findings suggest that the cecectomy method is more suitable than the slaughter method to determine the digestibility of AA.

127 Standardized Amino Acid Digestibility and Protein Quality of Extruded Canine Diets Containing Hydrolyzed Protein

Abstract Hydrolyzed protein in companion animal diets has been of public interest because of itsdecreased susceptibility to elicit overreacting immune response and the potentially easier digestion. Thus, the objective of this study is to determine the chemical composition, standardized amino acid digestibility, and protein quality of 2 test protein hydrolysates, chicken liver hydrolysate (CLH) and chicken hydrolysate (CH), compared with a traditional chicken meal low ash (CM) in extruded canine diets. Five treatment diets were formulated to have similar ingredient compositions except for the main protein source, 1) CONd: CM diet; 2) 5%CLHd: 5% substitution of CLH of CM diet; 3) CLHd: CLH diet; 4) 5%CHd: 5% substitution of CH of CM diet; 5) CHd: CH diet. A precision-fed rooster assay using cecectomized roosters (n=4/treatment) was conducted to determine the standardized amino acid ileal digestibility and Digestible Indispensable Amino Acid Score (DIAAS) like values for the 3 protein ingredients and 5 extruded diets. The standardized ileal digestibility for the 10 indispensable amino acids was all equal or greatere than 80% in all protein sources and treatment diets. Tryptophan digestibility in 5%CLHd was less than CLHd (P &amp;lt; 0.05) but no difference was seen when compared with the other diets (P &amp;gt; 0.05). The DIAAS-like values of the diets according to AAFCO nutrient profile showed that tryptophan was the first limiting amino acid for CONd, 5%CLHd, and 5%CHd; the diets containing only protein hydrolysates had no limiting amino acid as their DIAAS-like values were greater than 100%. The DIAAS-like values were less in CONd (95.6%), 5%CLHd (94.9%), and 5%CHd (96.2%) compared with CLHd (104.5%) and CHd (116.9%) (P &amp;lt; 0.05). In conclusion, all test protein sources were well digested; however, substituting CM with protein hydrolysate could increase protein quality in canine extruded diets.

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.