Standardized Amino Acid Digestibility Research Articles

Nutritional evaluation of 3 types of novel ethanol coproducts

Five 48-h precision-fed rooster assays were conducted with the objective to determine true metabolizable energy (TMEn) using conventional roosters and/or standardized amino acid digestibility using cecectomized roosters for distillers dried grains with solubles (DDGS) produced from human food waste at high solids content (FWDDGS), DDGS produced from 4 corn hybrids with increases in grain protein concentration or the concentrations of several dietary indispensable amino acids, and a coproduct that is produced by a process which separates a high protein and yeast fraction from ethanol stillage (Still Pro, Fluid Quip Process Technologies, Cedar Rapids, IA). These results from the first cecectomized rooster assay indicated that the standardized digestibility values for Lys, Met, Cys, Thr, and Val were 61, 75, 70, 70, and 72%, respectively. Using conventional roosters, the TMEn for the FWDDGS was 3,890kcal/kg DM. The DDGS produced from the high protein mutant corn hybrid had a higher protein content of 34% compared with 28% protein for DDGS from the control corn hybrid. Using Lys as an example, there was a large difference between the 2 samples; the high protein mutant DDGS contained 1.60% Lys vs 1.05% for the control DDGS. Standardized digestibility of amino acids was generally not different for the mutant DDGS and the control DDGS. Similar results were observed for Lys, Arg, and Trp for the DDGS produced from the second mutant corn hybrid. The Still Pro sample was analyzed to contain 53% protein (DM basis) with 2.22% Lys, 1.05% Met, 0.90% Cys, 2.06% Thr, and 3.08% Val. The standardized digestibility values for these amino acids were 84, 92, 87, 86, and 87%, respectively. The TMEn of the Still Pro sample was determined to be 3,372kcal/kg DM. In conclusion, the results of this study indicate that the nutritional value of the 3 types of novel ethanol coproducts is equal to or superior to the nutritional values generally reported for conventional DDGS.

Nutritional evaluation of two barley cultivars, without and with carbohydrase supplementation, for broilers: metabolisable energy and standardised amino acid digestibility

ABSTRACT 1. Two experiments were conducted to assess the nitrogen-corrected apparent metabolisable energy (AMEn; Exp. 1; 288 Ross 308 male broilers at d 14; 36 cages with eight birds each) and coefficient of standardised ileal digestibility (CSID) of amino acids (AA; Exp. 2; 336 Ross 308 male broilers at d 21; 42 cages with eight birds each) of two barley cultivars for broilers in comparison to wheat, without or with a multi-component non-starch polysaccharide (NSP) degrading enzyme. A 3 × 2 factorial arrangement of treatments was used in both experiments with three types of grains (normal starch hulled barley [NSH], waxy starch hull-less barley [WSHL], and wheat) and two levels of enzyme supplementation (0 and 200 g/tonne of feed). Enzyme supplemented diets contained 406 and 128 of endo-1, 4-β-xylanase and endo-1, 3 (4)-β-glucanase units per kg of feed, respectively. 2. Analysis showed that the starch content was higher in NSH (610 g/kg) than in wheat (537 g/kg) and WSHL (554 g/kg), and the composition of starch differed markedly among the grain types. The β-glucan content was considerably higher in WSHL (68.6 g/kg) compared to NSH (38.5 g/kg) and wheat (7.74 g/kg). The contribution of soluble fraction to the total non-starch polysaccharides was higher in WSHL (38.2%) compared to NSH and wheat (17.1% and 13.3%, respectively). 3. A significant (P < 0.01) interaction was observed between the grain type and enzyme supplementation for AMEn. The WSHL, with the highest content of β-glucan, showed the greatest response to enzyme supplementation for AMEn. 4. Birds fed wheat- and WSHL-based diets had the highest and lowest CSID of nitrogen and most of AA, respectively, with NSH diets being intermediate. Regardless of grain type, enzyme supplementation increased (P < 0.05) the CSID of nitrogen. 5. These data suggest that β-glucan content plays an important role in determining the digestibility of nutrients in barley for broilers, resulting in a better feeding value for NSH over WSHL. Supplementation of a multi-component NSP-degrading enzyme can improve the feeding value of barley in broiler diets by increasing the digestibility with the effect being more pronounced in WSHL barley.

Characterization of plant-based protein sources for use in canine and feline nutrition

The objective of this study was to determine the macronutrient composition and standardized amino acid digestibility of 14 novel, plant-based, protein sources. The 14 protein sources are comprised of protein concentrates (pea, potato, faba bean, yeast, and soy concentrates), pulses (garbanzo beans, navy beans, black beans, lentils, and peas), and byproducts (corn gluten meal, peanut flour, soybean meal, and soy flakes). Macronutrient compositions and a complete amino acid profile were analyzed for all 14 protein sources. Cecectomized roosters (n=4/treatment) were utilized in a precision-fed rooster assay to measure standardized amino acid digestibility and true metabolizable energy corrected for nitrogen (TMEn). The roosters were precision-fed 30g of a 1:1 ratio of an ingredient and corn mixture. Excreta was collected after 48h, freeze-dried, and analyzed for a complete amino acid profile. Due to the high amino acid digestibility and well-balanced essential amino acid profiles, these plant-based proteins have the potential to become viable protein sources in canine and feline diets.

Influence of wet heating and autoclaving on chemical composition and standardized ileal crude protein and amino acid digestibility in full-fat soybeans for pigs.

One batch each of eight full-fat soybeans (FFSB) was used to determine the effect of different heat treatments including wet heating (WH) and autoclaving (AC) on chemical composition and standardized ileal digestibility (SID) of CP and AA in growing pigs. The raw FFSB (K0) were either treated by WH at 80°C for 1 min (K1), at 100°C for 6 min (K2), or at 100°C for 16 min (K3). Thereafter, these batches were expanded at 125°C for 15 s. A further heat treatment included AC at 110°C for 15 (Z1), 30 (Z2), 45 (Z3), or 60 (Z4) min of FFSB that were subjected to the same WH treatment as K3. Diets were formulated to contain the respective FFSB as the sole source of CP and AA. A N-free diet was used to measure basal endogenous losses of CP and AA in an additional period at the end of the experiment. Eight ileally cannulated pigs (28 ± 1 kg) were allocated to a row-column design with 8 diets and 6 periods of 7 d each. An increase in the duration of WH had no effect on contents of AA (% of CP) and NDF, but NDIN contents linearly increased ( < 0.05) with increasing time for WH. Autoclaving resulted in a linear decrease ( < 0.05) of trypsin inhibitor activity (TIA), contents of Arg, Leu, Ala, Asp, Cys, and Gly as well as Lys to CP ratio (Lys:CP), reactive Lys to CP ratio (rLys:CP), and in an increase ( < 0.05) in contents of NDF and NDIN. There was a quadratic response ( < 0.05) of SID of CP and AA as time for WH at 100°C increased from 0 (K0) to 6 (K2) up to 16 (K3) min. Moreover, a quadratic response ( < 0.05) to increasing time of AC was observed for SID of Arg, Phe, and Pro. The SID of CP and all indispensable AA showed a quadratic response ( < 0.05) to decreasing TIA, urease activity, protein solubility in 0.2% potassium hydroxide, protein dispersibility index, Lys:CP, (lightness), and to increasing NDIN and (redness). In addition, there was a linear increase ( < 0.05) in SID values with decreasing rLys:CP and increasing NDF contents. In conclusion, WH proved to be suitable for increasing SID values. Further improvement of SID of most AA could be achieved on additional AC treatment from Z1 to Z3, however, it needs to be considered, if the observed increase due to AC is cost effective in view of the additional production costs. Several chemical and physical parameters can be used in the feed industry for quality control purposes to predict the extent of heat damage on SID of CP and indispensable AA in FFSB.

Ileal Amino Acid Digestibility of Broken Rice Fed to Postweaned Piglets with or without Multicarbohydrase and Phytase Supplementation.

Most of amino acid (AA) digestibility values for feed ingredients are obtained using pigs cannulated in the distal ileum. The ileal-cannulated pig model uses pigs older than six weeks due to difficulties related to implanting the T-cannula in distal ileum of younger pigs and complications during the post-surgical recovery. However, to properly formulate the diet of weaned pigs, the nutritive value of feed ingredients should be determined with younger pigs. Thus, 25 weaned pigs were used to determine the apparent total tract digestibility (ATTD) of nutrients, energy, and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) ileal AA digestibility of broken rice (BR), with or without multicarbohydrase (MC) and phytase (Phy) supplementation. Piglets were weaned at 23 d of age and individually housed in digestibility cages until 45 d of age. The trial consisted of 7 d of adaptation to the experimental diets and 3 d of excreta (feces and urine) collection. Ileal digesta was collected at slaughter (about 6 weeks of age). A completely randomized experimental design was used to determine the effects of MC and Phy. Reference diets (RD, 5% casein) was replaced by 30% of BR with or without MC, Phy, or MC+Phy. The RD was used to quantify endogenous AA losses. BR with Phy supplied had increased the ATTD of dry matter (p<0.05) and SID of histidine (p = 0.05), arginine, leucine, lysine, valine, alanine, and proline (p<0.05). BR with MC had been increased digestible energy and protein and SID for histidine (p<0.05). There was no interaction between Phy and MC on the BR nutrient digestibilities. Standardized amino acid digestibilities of BR, without enzymes, were lower than those values reported in the literature. The MC and Phy improved the digestibility of some nutrients and energy of BR in post-weaned piglet diets.

Complete replacement of soybean meal in pig diets with hydrolyzed feather meal with blood by amino acid supplementation based on standardized lleal amino acid digestibility

The current study was conducted to determine the possibility of replacing soybean meal (SBM) in finisher pig diet completely with hydrolyzed feather meal (FM) with blood by supplementing with appropriate amino acids (AA) based on standardized ileal digestible (SID) AA in FM. Corn–SBM, positive control (POS) diets were formulated to contain 6.6 and 5.2g true ileal digestible (TID)Lys/kg to satisfy the requirements during the finisher-1 and finisher-2 phases, respectively. Corn–FM negative control (NEG) diets were formulated to be iso-N and iso-caloric to the POS diets. The NEG diets were supplemented with Lys and Trp to alleviate AA deficiencies based on TID AA values in FM reported by the NRC in 1998 (NRC). In addition, the NEG diets were supplemented with Lys and Trp to alleviate AA deficiencies based on the determined SID AA in FM (SID). When pigs weighed 50.0±2.9kg, 32 gilts and 32 castrated males (2 gilts or 2 castrated males/pen) were randomly assigned to 1 of 4 finisher-1 diets with 4 gilt pens and 4 castrated male pens/diet, and they were switched to finisher-2 diets when the average pen weight reached 79.0±2.0kg. Pigs had ad libitum access to feed and water throughout the study. At the end of the finisher-2 phase (107.7±3.3kg), blood samples were collected to determine serum metabolite profile and pigs were slaughtered to assess carcass characteristics. Pigs fed the POS diets ended to have greater overall average daily feed intake (ADFI; P=0.083) and had greater total Lys intake (P=0.029) than those fed the SID diets, which may have resulted in a tendency for slightly greater average daily gain (ADG; P=0.094) in pigs fed the POS diets. However, there was no difference in the efficiency of feed or Lys utilization. Pigs fed the SID diets tended to have greater gain:feed (G:F; P=0.057) and had greater gain:total Lys intake (P<0.001) than those fed the NRC diets. Pigs fed the POS diets tended to have greater ADFI (P=0.079) and had greater ADG (P<0.001) and G:F (P<0.001) than those fed the NEG diets, but, as expected, they had lower gain:total Lys intake (P<0.001) mostly because of the increased total Lys intake (P<0.001). Serum glucose was not affected by dietary treatments. Pigs fed the POS diets had greater urea-N (P=0.003) and lower cholesterol (P=0.002) than those fed the SID diets. As expected, pigs fed the NEG diet had reduced total protein (P<0.001) and increased urea-N (P=0.001), triglyceride (P<0.001), and cholesterol (P<0.001) compared with those fed the POS diets. Pigs fed the POS diets had greater fat-free lean gain (P=0.020) that those fed the SID diets, but similar loin muscle area, fat-free carcass percentage, and efficiency of fat-free lean gain. Results indicated that pigs fed the SID diets utilized feed and Lys as efficiently as those fed the POS diets, but they had slightly reduced body weight and fat-free lean gain, perhaps, because of slightly reduced intake of feed and total Lys, as well as other AA.

Comparison of amino acid digestibility coefficients for soybean meal, canola meal, fish meal, and meat and bone meal among 3 different bioassays

The objective of this study was to determine amino acid digestibility of 4 feedstuffs [soybean meal (SBM), canola meal, fish meal, and meat and bone meal (MBM)] using the precision-fed cecectomized rooster assay (PFR), the standardized ileal assay (SIAAD), and a newly developed precision-fed ileal broiler assay (PFC). For the PFR, cecectomized roosters were precision-fed approximately 30 g of feed sample, and excreta were collected 48 h postfeeding. For the SIAAD, 16-d-old broilers were fed a semipurified diet containing the feed samples as the only source of protein from 17 to 21 d, with ileal digesta collected at 21 d. For the PFC, 22-d-old broilers were precision-fed 10 g of feed sample mixed with chromic oxide, and ileal digesta were collected at 4 h postfeeding. Digestibility coefficients were standardized using a nitrogen-free diet for the SIAAD and PFC and using fasted roosters for the PFR. There were generally no consistent differences in standardized amino acid digestibility values among assays, and values were in general agreement among assays, particularly for SBM and MBM. Differences did occur among methods for amino acid digestibility in fish meal; however, these differences were not consistent among methods or amino acids. The results of the study indicated that all 3 bioassays are acceptable for determining the amino acid digestibility of SBM, canola meal, MBM, and fish meal for poultry.

Comparison of amino acid digestibility of feedstuffs determined with the precision-fed cecectomized rooster assay and the standardized ileal amino acid digestibility assay

The objective of this study was to evaluate and compare amino acid digestibility of several feedstuffs using 2 commonly accepted methods: the precision-fed cecectomized rooster assay (PFR) and the standardized ileal amino acid assay (SIAAD). Six corn, 6 corn distillers dried grains with or without solubles (DDGS/DDG), one wet distillers grains, one condensed solubles, 2 meat and bone meal (MBM) and a poultry byproduct meal were evaluated. Due to insufficient amounts, the wet distillers grains and condensed solubles were only evaluated in roosters. Standardized amino acid digestibility varied among the feed ingredients and among samples of the same ingredient for both methods. For corn, there were generally no differences in amino acid digestibility between the 2 methods. When differences did occur, there was no consistent pattern among the individual amino acids and methods. Standardized amino acid digestibility was not different between the 2 methods for 4 of the DDG samples; however, the PFR yielded higher digestibility values for a high protein DDG and a conventionally processed DDGS. The PFR yielded higher amino acid digestibility values than the SIAAD for several amino acids in 1 MBM and the poultry byproduct meal, but it yielded lower digestibility values for the other MBM. Overall, there were no consistent differences between methods for amino acid digestibility values. In conclusion, the PFR and SIAAD methods are acceptable for determining amino acid digestibility. However, these procedures do not always yield similar results for all feedstuffs evaluated. Thus, further studies are needed to understand the underlying causes in this variability.

Standardised amino acid digestibility of wheat distillers’ dried grains with solubles in force-fed cockerels

1. In recent years, policies encouraging the production of ethanol from maize or wheat have stimulated an increased production of distillers’ dried grains with solubles (DDGS) for which the nutritional value for poultry is poorly described, especially in the case of wheat DDGS. 2. DDGS samples (19) were obtained from 7 plants in Europe from June to September 2007. Each sample was analysed for chemical composition and 10 representative samples were measured for amino acid (AA) content and their standardised digestibility (SDD) in caecectomised cockerels. Lightness score (L) of each DDGS was also measured. 3. Results indicated a rather stable crude protein content (327 to 392 g/kg DM) but the AA profile was variable between samples. Lysine (LYS) was the most affected AA with contents ranging between 0·83 and 3·01 g/100 g CP. In addition, only 0·76 of total LYS were free if estimated by the fluoro-dinitro-benzene procedure and 0·85 of total LYS were free if estimated by the furosine procedure. 4. The SDD of LYS was also highly variable (−0·04 to 0·71) with the lowest values observed for DDGS samples with a low LYS content in CP; these latter samples had also a high occurrence of Maillard reactions and low L values (<50). Consequently, both LYS content in CP (r = 0·63) and SDD of LYS (r = 0·64) values were positively related with L. 5. Our data indicate that LYS SDD can be accurately predicted from LYS content in CP according to a quadratic (R 2 = 0·94) or a linear-plateau model (R 2 = 0·90; breakpoint for 1·9 g/100 g lysine in CP and a 0.63 plateau SDD value).

Comparison of amino acid digestibility of feed ingredients in broilers, laying hens and caecectomised roosters

1. This study determined the effect of bird type (broilers, laying hens, or caecectomised roosters) on amino acid digestibility of feedstuffs from 5 plant sources and one animal source. 2. The standardised amino acid digestibility (SAAD) were obtained by correcting apparent ileal amino acid digestibility (AIAAD) values for basal ileal endogenous amino acid (EAA) flow obtained by feeding a N-free diet (NFD) to broilers and laying hens or from fasted EAA flow from caecectomised roosters. 3. The apparent total amino acid (TAA) digestibilities did not differ between broilers and roosters for three of the 6 feed ingredients. 4. Broilers had higher apparent total amino acid (TAA) digestibility than laying hens and roosters when fed on the maize diet (canola meal, maize, and soybean meal). 5. The apparent TAA digestibilities were similar across bird types for the dark distillers’ dried grain with solubles, but the apparent lysine digestibility was much lower in the caecectomised roosters (15%) than the broilers (49%) and laying hens (43%). 6. The standardised TAA digestibility values in roosters were higher than in broilers for three of the 6 feed ingredients (canola meal, soybean meal, or meat and bone meal). 7. There were no differences between broilers and roosters, however, in the standardised TAA digestibility values for maize, dark and light DDGS. 8. The standardised TAA digestibility values for laying hens were lower for maize, higher for meat and bone meal, but no different for the remaining ingredients when compared with broilers. 9. The results from this study showed that both the apparent and standardised amino acid digestibility values in caecectomised roosters, laying hens, and broilers ingredients are similar for some, but not all, feed ingredients. 10. Nutritionists should, therefore, be cautious about using digestibility coefficients obtained by different methodologies as values may differ.

Standardized amino acid digestibility in cecectomized roosters and lysine bioavailability in chicks fed distillers dried grains with solubles

This study was conducted to compare the concentration of standardized digestible (SDD) Lys and relative bioavailable Lys in 7 sources of corn distillers dried grains with solubles (DDGS). A second objective was to evaluate 2 in vitro methods, reactive Lys and color score, to predict the concentration of SDD Lys and bioavailable Lys in DDGS. Seven sources of DDGS were fed to cecectomized roosters, and digestibility of amino acids was measured using the total excreta collection method. To measure the relative bioavailable Lys in DDGS, a standard curve (r2 = 0.96, P < 0.01) was constructed from 9-d weight gain of young chicks fed a Lys-deficient basal diet or diets containing increasing concentrations of l-Lys-HCl. Seven additional diets were formulated by adding each of the 7 sources of DDGS to the basal diet, and total weight gain of chicks was measured. Weight gain of chicks fed each DDGS-containing diet was then compared with the standard curve to calculate the bioavailable Lys and bioavailability of Lys in each source of DDGS. All DDGS sources were analyzed for reactive Lys using the guanidination procedure, and a Hunterlab color score was used to measure the degree of lightness (L), redness (a), and yellowness (b). Results showed that the mean SDD Lys values and the mean relative bioavailability of Lys were 61.4 and 69.0%, respectively. Differences between the concentration of SDD Lys and the concentration of bio-available Lys were not observed in 5 of 7 sources of DDGS. The concentration of SDD Lys was correlated (r2 = 0.84, P < 0.05) with the concentration of reactive Lys in DDGS. Greater Hunterlab L scores were associated with a greater (r2 = 0.90, P < 0.05) concentration of bioavailable Lys in DDGS. In conclusion, the concentration of SDD Lys in DDGS does not overestimate the concentration of bioavailable Lys for poultry. Values for reactive Lys may be used to estimate the concentration of SDD Lys, whereas Hunterlab L may be used to estimate the concentration of bioavailable Lys in DDGS.

Determination of standardized ileal crude protein and amino acid digestibilities in protein supplements for piglets

The objective of the study was to determine standardized ileal digestibilities (SID) of crude protein (CP) and amino acids (AA) in six ingredients commonly used in weanling pigs diets. The ingredients consisted of extruded soybeans (SBe), high-protein soybean meal (SBMhp), soy protein concentrate (SPC), hydrolyzed wheat gluten (WGh), conventional fish meal 1 (FM1) and extracted fish meal 2 (FM2e). Each assay feed ingredient was added to a purified cornstarch-based basal diet supplemented with casein and crystalline AA, and SID of CP and AA of assay ingredients were estimated using the difference method. A total of 12 3-week-old barrows were surgically fitted with T-cannulas at the distal ileum. The piglets were allocated to four simultaneous 3 × 3 Latin-square designs with three animals and three periods each, resulting in six observations per assay diet. After 3 to 5 days recovery from surgery, each assay diet was fed at a level of 30 g/kg body weight. Each experimental period consisted of 5 days for adaptation to the assay diets and 2 days for ileal digesta collection. The SID of CP, Lys, Met, Thr and Trp were 73%, 78%, 76%, 66% and 71% in SBe; 80%, 84%, 87%, 75% and 81% in SBMhp; 86%, 89%, 89%, 78% and 83% in SPC; 87%, 60%, 88%, 76% and 79% in WGh; 87%, 92%, 94%, 86% and 86% in FM1; and 79%, 86%, 89%, 80% and 74% in FM2e, respectively. The greatest SID of indispensable AA were observed for FM1 and SPC (SID ⩾ 85% for most indispensable AA), followed by WGh, FM2e and SBMhp (SID ⩾ 80% for most indispensable AA) and the smallest SID were obtained for SBe (SID < 80% for most indispensable AA). The SID of CP and indispensable AA in both types of fish meal, SBMhp and WGh were similar to SPC (P = 0.063 to 0.855), except for Arg (P = 0.010) and Lys (P = 0.001) in WGh, and Phe (P = 0.044) and Trp (P = 0.037) in FM2e. The SID of CP and indispensable AA were smaller in SBe compared with SPC (P < 0.001 to P = 0.017), except for Lys (P = 0.136). The SID of CP and indispensable AA were consistently smaller in FM2e compared with FM1 with significant differences for CP (P = 0.035), Phe (P = 0.028) and Trp (P = 0.008). Digestibility values measured in the present study can be used to formulate diets for piglets based on standardized ileal digestible contents of CP and AA.

A new protein evaluation system for pig feeds and its practical application

The present basis for determining the protein value in pig feeds is discussed and a proposal for a new protein evaluation system is presented. The system proposed includes (i) a quantification of digestible amino acids according to their ileal digestibility, determined using standardized methods; (ii) a characterization of the protein value according to the contribution of digestible amino acids to ideal protein; (iii) a calculation of surplus amino acid‐N; and (iv) a calculation of the physiologically available energy of surplus amino acids. Practical methods for improving the quantification of digestible amino acids in the actual samples are described. The methods include calculations of (i) total amino acids in feedstuffs from nitrogen analyses by the use of specific factors or regression equations and (ii) standardized digestible amino acids from in vitro digestible nitrogen and correction for the extra endogenous amino acid losses specifically induced by the feedstuff itself. An example calculation for the practical use of the proposed protein evaluation system is given.