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Objective The objectives were to quantify collagen content in nonlactating uninfected and Staphylococcus aureus–infected mammary glands and determine the relative abundance of collagen in different gland regions. Materials and Methods Mammary tissues that were previously collected from a mastitis-challenge trial were examined. Mammary tissues were collected along a vertical midline through each gland and included parenchymal tissues that were proximal to the gland cistern (cisternal parenchyma) and tissues near the abdominal wall (deep parenchyma) from each saline-infused (n = 18) and Staph. aureus–infused (n = 18) gland. Collagen was detected via picro-sirus red staining and visualized using polarized light for image acquisition and subsequent analysis. Results and Discussion Most interlobular collagen was associated with larger ducts and stromal tissues. Some collagen was intralobular and was mostly associated with these larger ducts but was also present in epithelial basement membranes. Staphylococcus aureus–infused glands contained more tissue area occupied by collagen than saline-infused glands (19.78 vs. 17.26 ± 1.19%). Additionally, parenchyma near the gland cistern contained more collagen than deep parenchyma (19.95 vs. 17.09 ± 1.19%). Results indicate that mastitis elicits the deposition of collagen in affected glands and that collagen abundance is affected by gland region. Implications and Applications Nonlactating mammary glands affected by Staph. aureus mastitis may have a greater amount of collagen, believed to be resulting scar tissue. We speculate that it may have long-term, and possibly irreversible, effects on glandular structure and, consequently, lifetime productivity.

Three experiments were conducted to determine ileal P digestibility and excreta P retention values for canola meal (CM) using 3 different types of balance assays. The first experiment was an ad libitum–fed chick experiment which evaluated the effect of phytase on ileal P digestibility and excreta P retention values. Chicks were fed a P-deficient cornstarch–dextrose-45% CM basal diet (0.13% nonphytate P) as diet 1 or that diet plus 125 or 250 FTU/kg of phytase, respectively, from 8 to 21 D of age. The digestibility/retention of P was 38% and phytase linearly increased both ileal digestibility and excreta retention of P (P

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

Two chicken assays were conducted to determine P availability, using three different approaches, for 2 black soldier fly larvae meals (BSFL 1 and 3) and one partially-defatted BSFL. Experiment 1 was conducted to determine ileal P digestibility and total tract P retention. Three experimental diets containing a BSFL as the only source of P were fed to broiler chickens from 19 to 22 days of age. Each diet contained 0.25% total dietary P. Ileal digesta and excreta were collected on day 22. Ileal digestibility of P was 87%, 75%, and 88% for BSFL 1, BSFL 3, and partially-defatted BSFL, respectively. Total tract P retention was 87%, 73%, and 85% for BSFL 1, BSFL 3, and partially-defatted BSFL, respectively. The objective of experiment 2 was to determine the relative bioavailability of P in the 3 insect meals relative to KH2PO4 using a chicken bone ash bioassay. Chickens were fed one of nine dietary treatments from 8 to 22 days of age. These diets included a P-deficient cornstarch-dextrose-SBM based diet (0.14% nonphytate P) or that diet supplemented with 0.05% or 0.10% P from KH2PO4, 7% or 14% BSFL 1, 8%, or 16% BSFL 3, and 8% or 16% partially-defatted BSFL. The slope-ratio method using multiple regression for tibia ash regressed on supplemental P intake was used to calculate the relative bioavailability of P where values for BSFL 1, BSFL 3, and partially-defatted BSFL were 54%, 51%, and 57%, respectively, relative to KH2PO4. The results of this study indicated that availability of P in BSFL based on ileal P digestibility and total tract P retention values was high, whereas relative bioavailability values for P based on tibia ash were approximately 20 to 30 percentage units lower.

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

Chicken-based ingredients are commonly used in pet food products, but vary greatly in nutrient composition and processing conditions that may affect their protein quality and digestibility. Testing the quality of protein sources undergoing different processing conditions provides important information to pet food producers. The objective of this study was to determine the chemical composition, nutrient digestibility, protein, and AA digestibility scores, and nitrogen-corrected true metabolizable energy (TMEn) of chicken-based ingredients that had undergone different processing conditions (i.e., chicken meal, raw chicken, retorted chicken, and steamed chicken) using the precision-fed cecectomized rooster assay. True nutrient digestibility was variable among the protein sources (60% to 76% of DM, 66% to 81% of OM, 83% to 90% of AHF, 50% to 95% of AA and 73% to 85% of TMEn/GE). In general, the chicken meal had a lower (P < 0.05) nutrient digestibility than other ingredients tested, including DM, OM, and most indispensable and dispensable AA, with most having a true digestibility between 75% and 85%. The steamed chicken had the highest indispensable AA digestibilities, with all having a true digestibility greater than 88% and most being over 90%. TMEn value and digestible indispensable AA scores (DIAAS)-like values were higher (P < 0.0001) in the less processed chicken-based ingredients in comparison to chicken meal. Although animal proteins are often considered to be complete proteins, DIAAS-like values

Four experiments were conducted to evaluate the precision-fed rooster assay for determining excreta phosphorus retention values for 5 feed ingredients in which roosters were precision-fed the ingredients and excreta were collected quantitatively for 48 h. The first rooster assay determined the effects of increasing P intakes on excreta P retention values for corn. This assay involved feeding either 20 g of corn or 20 g of corn supplemented with increasing amounts of KH2 PO4 to provide total P intakes of 51 to 351 mg and non-phytate P intakes of 16 to 316 mg. The excreta P retention value for corn fed alone was 75% but decreased greatly when non-phytate P intakes were 76 mg or higher for the corn diets containing added KH2 PO4. The second precision-fed rooster assay involved feeding increasing amounts of spray dried plasma protein (SDPP) (5 to 20 g) which provided non-phytate P intakes of 61 to 242 mg. Excretion of P increased and excreta P retention values decreased from 94 to 60% as SDPP intake increased from 5 to 20 g. Experiment 3 determined excreta P retention values for solvent extracted dehulled soybean meal (SBM) (24 g intake) and also the effect of increasing intakes of SDPP (5 to 10 g) and meat and bone meal (MBM) (1.5 to 10 g) on their excreta P retention values. The excreta P retention value for SBM was 41%. Excreta P retention values for SDPP again decreased as P intake increased. Excreta P retention values for MBM were low (27 to 35%) at all intakes. In Experiment 4, roosters were tube-fed 8, 16, or 24 g of canola meal and excreta P retention values varied from 23 to 35% among intake levels. The results of this study indicated that excreta P retention values often varied greatly among different levels of ingredient and non-phytate phosphorus intake and suggest that the precision-fed assay may be useful for determining bioavailability of P only if non-phytate P intakes are low. In addition, the assay may not be accurate for ingredients which contain high Ca levels such as MBM.

Black soldier fly larvae (BSFL) are an alternative protein source for animals, including dogs and cats. Dietary calcium source is an essential nutrient for BSFL development in the pupal stage. Calcium carbonate (CaCO3) and calcium chloride (CaCl2) are common calcium sources but differ in solubility, acid-binding capacity, and calcium concentration. A high calcium concentration in BSFL may affect how well nitrogen and amino acids (AA) are digested by animals consuming them, thereby affecting feed conversion efficiency. Our objective was to determine the effects of dietary calcium form and concentration on nutrient composition, AA digestibility, and digestible indispensable amino acid score (DIAAS)-like values of BSFL intended for use in animal feeds using the precision-fed cecectomized rooster assay. All BSFL tested in this study were harvested at 18 d after hatch. Industry standard rearing conditions were maintained and a commercial layer ration was fed to all BSFL until 11 d post-hatch. From day 11 to 18, BSFL were fed a combination of distiller’s dried grains with solubles from a distillery, bakery byproduct meal, and varied calcium sources. All BSFL diets contained 0.2% calcium in the basal diet plus additional calcium in the following amounts and forms: BSFLA: 1.2% CaCl2, BSFLB: 1.2% CaCO3, BSFLC: 0.75% CaCO3, and BSFLD: 0.6% CaCO3 + 0.6% CaCl2. On day 18, BSFL were washed and frozen. Prior to the rooster assay, BSFL were lyophilized and ground. In total, 16 cecectomized roosters (4 roosters per substrate) were randomly assigned to test substrates. After 24 h of feed withdrawal, roosters were tube-fed 20 g of test substrates. 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 a completely randomized design and the GLM procedure of SAS 9.4. Nutrient and AA digestibilities were not different among substrates. DIAAS-like values were calculated to determine protein quality according to the Association of American Feed Control Officials nutrient profiles and National Research Council recommended allowances for dogs and cats. Although AA digestibilities did not differ, those containing CaCO3 generally had higher DIAAS-like reference values than the diet containing CaCl2 alone (BSFLA). Aromatic AA (Phe + Tyr) and sulfur AA (Met + Cys) were often first-limiting AA. Our results suggest that calcium sources fed to BSFL did not affect AA digestibility and protein quality.

Traditionally, protein by-products from oil seeds and cereal grains have been used in pet foods as sustainable, inexpensive, and protein-rich ingredients. However, the on-going demonization of soy- and corn-based ingredients continue to hinder their use in pet food and treat formulations. Ideally, the further demonstration of their protein quality and nutrient composition may encourage their favorable return as acceptable ingredients in pet foods and treats. Therefore, the objectives of this study were to determine the macronutrient composition, indispensable amino acid profile, standardized amino acid digestibility, true metabolizable energy content corrected for nitrogen (TMEn), and digestible indispensable amino acid scores (DIAAS-like) of soy flakes (SF), peanut flour (PF), soybean meal (SBM), and corn gluten meal (CGM). Standardized amino acid digestibility was assessed using the precision-fed cecectomized rooster assay. All test ingredients demonstrated a profile of highly digestible indispensable amino acids except for lysine in PF, which was lowest (P < 0.05) at 45.5%. The SBM and CGM had the highest (P > 0.05) digestibilities of indispensable amino acids. A DIAAS-like value was calculated for each ingredient using either AAFCO (2020) recommended values or NRC (2006) recommended allowances as the reference protein pattern. For adult dogs compared to AAFCO recommended values, the first-limiting amino acid was lysine for PF and CGM but it was methionine for SF and SBM. For adult cats compared to AAFCO recommended values, the first-limiting amino acid was lysine for PF and CGM but it was threonine for SF. There was no first-limiting amino acid in SBM for cats as DIAAS-like values were over 100% for all indispensable amino acids. The TMEn values were highest (P < 0.05) for PF and CGM (4.58 and 4.31 kcal/g [dry matter basis], respectively). The protein quality of these plant-based protein by-products reflects their value as nutritional ingredients for canine and feline diets. However, the prior processing of these by-products must be considered before exposing them to additional processing methods, such as extrusion. Additionally, the inclusion of complementary proteins or supplemental amino acids will be needed to meet all indispensable amino acid requirements for a portion of nutritionally complete and balanced pet food.

Increased consumer interest in high-quality and novel protein sources has driven the demand for the inclusion of protein-rich ingredients in companion animal diets. Novel protein concentrates, with protein contents of at least 50%, have been used to satisfy these consumer demands. However, minimal information is available regarding the macronutrient composition and protein quality of these ingredients that is needed for proper formulation of pet foods. Therefore, the objectives of this study were to determine the macronutrient and amino acid compositions, standardized amino acid digestibility according to the precision-fed rooster assay, and protein quality using digestible indispensable amino acid score (DIAAS like) of pea protein (PP), potato protein (POP), faba bean protein (FBP), soy protein concentrate (SPC), and dried yeast (DY). Precision-fed rooster assays were conducted using cecectomized roosters to calculate standardized amino acid digestibility and true metabolizable energy corrected for nitrogen (TMEn). For all five protein concentrates, all essential amino acids were highly digestible (88.0% to 96.3%, dry matter basis) with differences (P < 0.05) in only lysine, methionine, and tryptophan digestibilities. The TMEn values were highest for POP (4.22 kcal/g) and DY (3.61 kcal/g). The DIAAS-like values for adult dogs indicated that methionine was the first-limiting amino acid in all protein concentrates except POP, where the first-limiting amino acid was tryptophan. Using Association of American Feed Control Officials (AAFCO)-recommended values for adult cats, DIAAS-like values for methionine were lowest (P < 0.05) for FBP at 81.5%, with all other amino acids for all protein concentrates over 100%. The National Research Council (NRC)-recommended allowances for adult cats indicated that DIAAS-like methionine values for PP (92.7%) and FBP (73.8%) were significantly lower (P < 0.05) with these being the first-limiting amino acids, with the remaining amino acids above 100% for the other protein concentrates. The protein quality and high essential amino acid digestibility of these protein concentrates indicate that they would be viable protein sources in canine and feline diets. However, additional complementary protein sources should be included to meet the requirements of all essential amino acids.

The rising consumer demand for alternative and sustainable protein sources drives the popularity of the use of plant-based proteins in the pet food industry. Pulse crops, which include beans, peas, lentils, and chickpeas, have become an important addition to both human and animal diets due to their protein content and functional properties. However, knowledge of their nutrient composition and protein quality is necessary for the proper formulation of these ingredients in pet foods. The objective of this study was to determine the macronutrient composition and standardized amino acid digestibility and to describe the protein quality through the use of digestible indispensable amino acid scores (DIAAS-like) of five pulse ingredients. Black bean (BB) grits, garbanzo beans (GB), green lentils (GL), navy bean (NB) powder, and yellow peas (YP) were analyzed for dry matter (DM), ash and organic matter (OM), crude protein (CP), gross energy (GE), acid hydrolyzed fat (AHF), and total dietary fiber (TDF) to determine the macronutrient composition. Precision-fed rooster assays were conducted using cecectomized roosters to calculate standardized amino acid digestibility and true metabolizable energy corrected for nitrogen (TMEn). The essential amino acids, with the exception of methionine, were highly digestible with digestibility values of 80% to 90% (dry matter basis) for all selected pulse ingredients. BB grits had the lowest (P < 0.05) digestibility of arginine (86.5%) and histidine (80.6%) in contrast to GB (94.9% and 89.9%, respectively). The TMEn of GB was highest (P < 0.05) at 3.56 kcal/g compared with the other pulses. The DIAAS-like values for adult dogs were consistently the lowest for methionine for all pulses, making it the first-limiting amino acid in these ingredients. The DIAAS-like values for adult cats showed GL had lowest (P < 0.05) score in tryptophan compared with other pulses when using both AAFCO values and NRC recommended allowances as reference proteins. Methionine was the first-limiting amino acid for YP and tryptophan for GL. Based on macronutrient composition, protein quality, and amino acid digestibility, it can be concluded that pulse ingredients have the required nutritional characteristics to be viable protein sources in canine and feline foods. However, the use of complementary protein sources is recommended to counterbalance any potential limiting amino acids in pulse ingredients.

Three experiments were conducted to determine phosphorus (P) digestibility and bioavailability using different methods. The objective of the first experiment was to determine ileal P digestibility of soybean meal (SBM), meat and bone meal (MBM), and spray-dried plasma protein (SDPP) using a precision-fed broiler chick assay. This assay involved feeding 8 g of SBM, MBM, or SDPP to broiler chicks at 21 D of age. At 6 h after feeding, ileal digesta were collected. Ileal P digestibility of SBM, MBM, and SDPP was 64, 42, and 94%, respectively. In the second experiment, ileal P digestibility and excreta P retention of SBM, SDPP, and MBM were determined using an ad libitum fed chick assay. On day 17 of age, chicks were placed on 1 of 12 dietary treatments that consisted of diets containing increasing levels of SBM, SDPP, or MBM. On day 21, ileal digesta and excreta were collected. True ileal P digestibility and true excreta P retention estimated using regression of ileal P or excreta P output on dietary P content yielded true ileal P digestibility values for SBM, SDPP, and MBM (2 diet methods for MBM) to be 83, 98, 61, and 23%, respectively. True excreta P retention values for SBM, SDPP, and MBM (2 methods) were determined to be 51, 99, 32, and 53%, respectively. The third experiment determined bioavailability of P in SBM, SDPP, and MBM relative to KH2PO4 using a chick bone ash bioassay. Dietary treatments included a P-deficient cornstarch–dextrose–SBM diet supplemented with 2 increasing levels of P from KH2PO4, SBM, SDPP, or MBM. Bioavailability of P based on tibia ash estimated using the multiple regression slope ratio method was 36, 125, and 76% for SBM, SDPP, and MBM, respectively, relative to KH2PO4. The results of this study indicated the digestibility/relative bioavailability of the P in SDPP was very high for all 3 methods, but values for SBM and MBM varied greatly among different methods.

Calves can be ruminally cannulated at young ages, but equipment size limitations preclude use of an infusion and sampling device in these small animals. Likewise, a procedure to easily evacuate rumen contents in young calves has not been described. Overcoming these technical complications related to assessment of ruminal passage kinetics, nutrient digestion, and volatile fatty acid absorption would aid in future studies advancing our knowledge of dairy calf nutrition. The first objective was to design and fabricate 2 devices (one device for infusion and sampling, and another for vacuum-assisted collection) suitable for use in young ruminally cannulated dairy calves. The second objective was to test the utility of these tools when performing procedures commonly used in ruminant nutrition research. A single weaned 62-d-old ruminally cannulated calf was used to evaluate the ability to infuse a solution of LiCoEDTA and sample rumen contents through the cannula cap over a period of 2 h to assess the rumen liquid passage rate (procedure 1). The device was capable of infusing the LiCoEDTA and sampling the rumen fluid, as evidenced by the presence of elevated Co concentrations in the sampled rumen fluid. Using the fluid samples obtained, liquid passage rate within the calf was estimated to be 40.2% of ruminal fluid/h. The second procedure tested the vacuum-assisted collection device and consisted of evacuating and weighing the rumen contents, which is considered a key preparatory step in washed reticulorumen technique experiments that aim to measure nutrient absorption. In agreement with existing literature, evacuated rumen contents represented approximately 4% of the calf's body weight. In conclusion, custom-built devices for infusion, sampling, and vacuum-assisted collection were efficacious when tested in a 62-d-old ruminally cannulated calf fed a diet of 100% texturized starter (18% crude protein, as-fed). Fellow scientists may employ and further modify these techniques to suit their needs when assessing passage kinetics, nutrient digestion, and volatile fatty acid absorption in calves.

Edible insects such as black soldier fly larvae (BSFL) are alternative protein sources for animal feeds due to their high protein content and low environmental footprint. However, protein quality and amino acid (AA) content may vary across insect species and life stage. Our objective was to determine the effects of life stage on true nutrient and AA digestibility of BSFL intended for use in animal feeds using the precision-fed cecectomized rooster assay. All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. 24 cecectomized roosters (4 roosters/substrate) were randomly assigned to test substrates [BSFL0= day 0 (day of hatch); BSFL11= day 11; BSFL14= day 14; BSFL18= day 18; BSFL23= day 23; BSFL29= day 29]. After 24h of feed withdrawal, roosters were tube-fed 20g of test substrates. Following crop intubation, excreta were collected for 48h. Endogenous corrections for AA were made using 5 additional cecectomized roosters. All data were analyzed using SAS 9.4. True dry matter, organic matter, and nitrogen digestibilities were not different among substrates, but acid-hydrolyzed fat tended to be greater (P < 0.10) for BSFL23 and BSFL29 than BSFL14 and BSFL18. Although all substrates had a high digestibility, BSFL0 and BSFL11 had the lowest (P < 0.05) digestibilities for most indispensable and dispensable AA. Digestible indispensable amino acid score (DIAAS)-like values were calculated to determine protein quality according to AAFCO nutrient profiles and NRC recommended allowances for dogs and cats. In general, BSFL18 had the highest and BSFL11 had the lowest DIAAS-like values for most indispensable AA. Threonine, methionine, and arginine were often the first-limiting AA. Our results suggest that BSFL are a high quality protein and amino acid source, but that life stage can affect the AA digestibility and protein quality of this novel protein source.

Edible insects such as black soldier fly larvae (BSFL) are alternative protein sources for animal feeds due to their high-protein content and potential low environmental footprint. However, protein quality and AA content may vary across insect species and age. Our objective was to determine the effects of age on nutrient and AA digestibility of BSFL intended for use in pet foods using the precision-fed cecectomized rooster assay. All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. Twenty-four cecectomized roosters (four roosters per substrate) were randomly assigned to test substrates [BSFL0 = day 0 (day of hatch); BSFL11 = day 11; BSFL14 = day 14; BSFL18 = day 18; BSFL23 = day 23; BSFL29 = day 29]. After 24 h of feed withdrawal, roosters were tube-fed 20 g of test substrates. 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 a completely randomized design and the GLM procedure of SAS 9.4. DM and OM digestibilities were not different among substrates, but acid-hydrolyzed fat digestibility tended to be greater (P < 0.10) for BSFL23 and BSFL29 than BSFL14 and BSFL18. Although all substrates had a high digestibility, BSFL0 and BSFL11 had the lowest (P < 0.05) digestibilities for most indispensable and dispensable AA. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to AAFCO nutrient profiles and NRC recommended allowances for dogs and cats. In general, BSFL18 had the highest, and BSFL11 had the lowest DIAAS-like values for most indispensable AA. Threonine, methionine, and tryptophan were often the first-limiting AA. Our results suggest that BSFL are a high-quality protein and AA source, but that age can affect the AA digestibility and protein quality of this alternative protein source.

Three experiments were conducted to evaluate 3 increased-protein, reduced-fiber canola meals (CM) (CMA, CMB, and Test CM), 2 conventional CM (CCM), and 2 soybean meals (SBM). For determination of P bioavailability in CM and SBM, a P-deficient cornstarch-dextrose-SBM basal diet was fed as Diet 1. The latter basal diet was then supplemented with 0.05 and 0.10% P from KH2 PO4 or 12.5 and 25% of a CM or SBM. In addition, the effect of phytase enzyme on bioavailability of the P in CMA, Test CM, and one of the CCM was determined using P-deficient 45% CM-cornstarch-dextrose diets (0.11 to 0.15% non-phytate P), with a CM as the only source of dietary P. Additional diets contained 0.05 and 0.10% added P from KH2 PO4 or 125 to 500 units phytase added per kg of diet. Crossbred chicks (New Hampshire X Columbian) were fed the experimental diets from 8 to 21 d post hatch in all experiments, and bioavailability of P was estimated using the slope ratio method in which tibia ash was regressed on supplemental P intake. A linear increase in tibia ash was observed as the P level increased by the addition of KH2 PO4, CMA, CMB, or SBM. Based on the mean values of tibia ash in mg/tibia and tibia ash %, the mean bioavailabilities of P in the 3 increased-protein, reduced-fiber CM, 3 CCM, and 2 SBM relative to KH2 PO4 were 18, 15, and 39%, respectively. A linear increase in weight gain and tibia ash was observed with addition of KH2 PO4 or phytase to the P-deficient CM diets. It was estimated that 125 or 250 units/kg microbial phytase resulted in approximately 0.05 and 0.10% P being released from CM, respectively. In conclusion, the bioavailablity of the P in the new increased-protein, reduced-fiber CM was similar to that of CCM. Furthermore, phytase substantially and similarly increased the bioavailability of P in both types of CM.

Background: Protein in the diet is commonly ingested from whole foods that contain various macro- and micronutrients. However, the effect of consuming protein within its natural whole-food matrix on postprandial protein metabolism remains understudied in humans.Objective: We aimed to compare the whole-body and muscle protein metabolic responses after the consumption of whole eggs with egg whites during exercise recovery in young men.Design: In crossover trials, 10 resistance-trained men [aged 21 ± 1 y; 88 ± 3 kg; body fat: 16% ± 1% (means ± SEMs)] received primed continuous l-[ring-2H5]phenylalanine and l-[1-13C]leucine infusions and performed a single bout of resistance exercise. After exercise, participants consumed intrinsically l-[5,5,5-2H3]leucine-labeled whole eggs (18 g protein, 17 g fat) or egg whites (18 g protein, 0 g fat). Repeated blood and muscle biopsy samples were collected to assess whole-body leucine kinetics, intramuscular signaling, and myofibrillar protein synthesis.Results: Plasma appearance rates of protein-derived leucine were more rapid after the consumption of egg whites than after whole eggs (P = 0.01). Total plasma availability of leucine over the 300-min postprandial period was similar (P= 0.75) between the ingestion of whole eggs (68% ± 1%) and egg whites (66% ± 2%), with no difference in whole-body net leucine balance (P = 0.27). Both whole-egg and egg white conditions increased the phosphorylation of mammalian target of rapamycin complex 1, ribosomal protein S6 kinase 1, and eukaryotic translation initiation factor 4E-binding protein 1 during postexercise recovery (all P < 0.05). However, whole-egg ingestion increased the postexercise myofibrillar protein synthetic response to a greater extent than did the ingestion of egg whites (P= 0.04).Conclusions: We show that the ingestion of whole eggs immediately after resistance exercise resulted in greater stimulation of myofibrillar protein synthesis than did the ingestion of egg whites, despite being matched for protein content in young men. Our data indicate that the ingestion of nutrient- and protein-dense foods differentially stimulates muscle anabolism compared with protein-dense foods. This trial was registered at clinicaltrials.gov as NCT03117127.

An experiment was conducted to test the hypothesis that the requirement for standardized total tract digestible (STTD) Ca by pigs from 100 to 130 kg depends on the concentration of STTD P in the diet. Ninety pigs (average initial BW: 99.89 ± 3.34 kg) were randomly allotted to 15 experimental diets. Each diet was fed to 6 replicate pigs using a randomized complete block design. Fifteen corn and soybean meal-based diets were formulated and phytate and Na were constant among treatments. Diets were formulated using a 3 × 5 factorial design with diets containing 0.11%, 0.21%, or 0.31% STTD P and 0.12%, 0.29%, 0.46%, 0.61%, or 0.78% total Ca (0.08%, 0.18%, 0.29%, 0.38%, or 0.49% STTD Ca). The P concentrations ranged from 48 to 152% of the STTD P requirement for 100- to 125-kg pigs and the Ca concentrations ranged from 27 to 173% of the total Ca requirement. Experimental diets were fed for 28 d and pigs were individually housed. Pig and feeder weights were recorded at the beginning and at the conclusion of the experiment to calculate ADFI, ADG, and G:F. On d 28, all pigs were euthanized and the right femur was extracted. Ash, Ca, and P concentrations were determined from the de-fatted, dried femurs. Results indicated that as dietary concentrations of STTD Ca increased, ADFI decreased (main effect of Ca, < 0.05), regardless of the dietary concentration of P. The model to predict ADFI (ADFI = 3.6782 - 1.2722 × STTD Ca [%]; = 0.001) was dependent only on the concentration of dietary STTD Ca, but not on the concentration of dietary STTD P. In contrast, the model to predict ADG depended on both STTD Ca and STTD P (1.4556 - 1.4192 × STTD Ca [%] - 1.0653 × STTD P [%] + 4.2940 STTD Ca [%] × STTD P [%]; = 0.002). There were no effects of STTD Ca or STTD P on G:F. Linear increases were observed for bone ash, bone Ca, and bone P as dietary concentrations of STTD Ca increased for all concentrations of STTD P, but the increase was greater at the greatest concentration of STTD P than at lower concentrations (interaction, < 0.001). In conclusion, results indicate that the estimated requirement for dietary STTD Ca by 100- to 130-kg pigs needed to maximize ADG, bone ash, and bone Ca depends on the concentration of STTD P in the diet. Results also indicate that feeding Ca in excess of the current requirement for total Ca is detrimental to growth performance of pigs from 100 to 130 kg unless P is also included above the requirement.

Demand for the inclusion of high-quality protein in companion animal diets has increased as owners have become more invested in the health of their pets. There is very little information on the nutrient content of novel proteins needed for a properly balanced diet, so as a result the objectives of this study were to determine the chemical composition, standardized amino acid digestibility using the precision-fed cecectomized rooster assay, and protein quality using digestible indispensable amino acid score (DIAAS like) of raw chicken, spirulina, cricket meal, and fish (carp) slurry. Raw chicken has the lowest crude protein concentration (45.6%) on dry matter (DM) basis, whereas fish slurry had the highest (75.3%). All amino acids were moderately to highly digestible (70.2% to 98.8%, dry matter basis) with differences (P < 0.05) in all but arginine, phenylalanine, threonine, cysteine, serine, and tyrosine. The limiting amino acid based on DIAAS-like values for adult dogs compared with the Association of American Feed Control Officials (AAFCO) recommended values were tryptophan for raw chicken and methionine for cricket meal. Comparing DIAAS-like values for adult dogs to National Research Council (NRC) recommended allowances, the limiting amino acids were the same where raw chicken and fish slurry still had tryptophan and spirulina and cricket meal had methionine as the first limiting amino acids. The DIAAS-like values for adult cats compared to AAFCO and NRC values were all above 100% with the lowest being threonine for chicken (123.65%) compared to AAFCO nutrient profile for adult cats and histidine for spirulina (123.13%) compared to NRC for cats at maintenance. Based on the data gathered in this study, the novel dietary protein sources evaluated are of similar or superior protein quality compared with raw chicken; a traditional protein source widely used in pet foods.

Concentrations of the essential amino acids, lysine and tryptophan, present in corn distillers dried grains with solubles (DDGS) are insufficient to fully meet the nutritional requirements in non-ruminant feeds. Mutations known to increase lysine and tryptophan concentrations were combined by breeding into two maize hybrid backgrounds that differ for grain protein concentration (FR1064 × Mo17 normal protein, FR1064 × IRHP1 high protein). These mutant hybrids were compared to their non-mutant control isolines for field performance and ethanol and DDGS processing using laboratory scale procedures: conventional dry grind process and modified dry grind process using granular starch hydrolyzing enzyme (GSHE). The mutant hybrid grain contained higher concentrations of a number of amino acids, with notable increases to at least 0.55% w/w lysine and 0.18% w/w tryptophan. Due to lower grain yield and starch concentrations, final ethanol yields of FR1064 × Mo17: o2; asaC28 hybrid were reduced compared to control for both the conventional and modified dry grind processes. However, with the modified process, ethanol yield for FR1064 × IRHP1: o2; asa2-C28 hybrid was similar to its control isoline. DDGS yields increased for both mutant hybrids compared to controls. Although amino acid profiles were similar for DDGS recovered from both the conventional and modified processes, DDGS from the mutant hybrids contained higher concentrations of lysine (1.48–1.70% w/w) and tryptophan (0.32–0.39% w/w) compared to controls (1.09% w/w lysine, 0.22% w/w tryptophan). Using these mutant corn hybrids at an ethanol plant resulted in lower ethanol yields; however, this loss can be recovered with the higher DDGS yield and increased nutritional value of the DDGS.

Our goal was to determine if relative bioavailability values (RBV) for fats and oils (lipids) determined in adult roosters are different than RBV determined with young broiler chickens. Lipids that were expected to have widely varying ME content were evaluated using a slope-ratio approach in adult roosters (Exp. 1) via the precision-fed rooster assay (PFRA) and broiler chicks via a growth assay (Exp. 2). The same lipids were tested in both experiments and were refined corn oil (RCO), a 2:1 blend of stearic acid (C18:0) with RCO (SAB1), a 1:1 blend of C18:0 with RCO (SAB2), tallow (TW), poultry fat (PF), and corn oil from a corn ethanol plant (DDGSCO). In Exp. 1, roosters were tube-fed diets containing 0, 5, and 10% of supplemental lipid in ground corn. In Exp. 2, diets consisted of 0, 5, and 10% supplemental lipid in an amino-acid fortified corn-soybean meal diet. Chicks were limit-fed test diets from 10 to 20 d posthatch to maintain energy as the growth-limiting factor. The TMEn of diets or BW gain of chicks were regressed on supplemental lipid level. The RBV were calculated as the regression coefficient of the test lipid divided by that of RCO. For Exp. 1 a non-linear response was observed for SAB2; however, the RBV for SAB1 (22%), TW (72%), PF (96%), and DDGSCO (90%) were as expected. The RBV of SAB1 and TW were lower (P

Experiments were conducted to evaluate conventional canola meal (Conv CM) and a new increased-protein reduced-fiber CM (Test CM). The Test CM contained higher levels of all digestible amino acids than the Conv CM as determined in 2 precision-fed rooster assays wherein Single Comb White Leghorn roosters were fasted for 24 h and then tube-fed 30 g of Conv CM or Test CM. Excreta were then quantitatively collected for 48 hours. All diets in 2 broiler experiments then were formulated to be equal in AMEn and digestible amino acids based on values from precision-fed rooster assays. In Experiment 1, diets were corn and soybean meal based and contained zero, 10, 20, 30 or 40% Conv CM from 2 to 21 d of age and zero, 10, 20 or 30% Conv CM from 21 to 37 d of age. In the starter phase of Experiment 1 (2 to 21 d), there was a significant negative effect (P 0.05) on weight gain and feed intake for CM levels in excess of 10%. In Experiment 2, both Conv CM and the new Test CM were evaluated. For the starter phase (2 to 19 d), the diets contained no CM or 8% Test CM or 8% Conv CM. For the grower phase (20 to 44 d), the chicks were fed diets that contained either no CM or 8, 16, or 24% of Test CM (Diets 2 to 4) or the same levels of Conv CM (Diets 5 to 7). The Test CM diets contained less soybean meal and less added fat than the Conv CM diets. There were no significant differences among dietary treatments for growth performance for either phase of Experiment 2. These results indicate that the new Test CM has increased levels of digestible amino acids compared to Conv CM and that up to 24% of either type of CM could be fed to broiler chickens during the grower phase with no statistical differences (P 0.05) in performance when diets were formulated to be equal in AMEn and digestible amino acids.

The influence of dietary Arg concentration and Eimeria acervulina infection on broiler growth performance and plasma carotenoid, nitric oxide (NO), amino acid, and urea concentrations was evaluated. Male Ross × Ross 308 broilers (384 total) were fed a common diet for 10 d post-hatch and provided experimental diets formulated to contain 1.23 (HA) or 0.74% (LA) standardized ileal digestible Arg from 10 to 28 d. At 21 d, one-half of the broilers were switched to the opposite diet to create 4 dietary regimens where birds were fed the LA diet throughout, the LA diet replaced by the HA diet at 21 d, the HA diet throughout, or the HA diet replaced by the LA diet at 21 d. Broilers were orally inoculated 0 (uninfected) or 3.5 × 105 sporulated E. acervulina oocysts at 15 d, resulting in a factorial arrangement of 4 dietary regimens × 2 infection states (8 replicates/treatment). Overall (10 to 28 d) BW gain and G:F were greatest (P 0.01) for birds fed the HA diet throughout, regardless of infection status. Eimeria acervulina infection decreased (P 0.01) BW gain of birds from 15 to 21 d, and G:F was lowest (P 0.05) for infected birds fed the LA diet during this period. There was no influence (P 0.05) of E. acervulina on BW gain or G:F of broilers from 21 to 28 d. Plasma Arg, Lys, and Orn levels at 21 d indicated that the LA diet caused an imbalance in the Lys and Arg status of broilers, and E. acervulina infection increased (P 0.01) the plasma concentration of these 3 amino acids. Diet × infection interactions (P 0.05) were observed on 21 d for plasma carotenoids and NO, whereby infection decreased plasma carotenoids and increased plasma NO, but dietary Arg concentration only influenced these measures for uninfected birds. Thus, production of NO during E. acervulina infection was not impaired by dietary Arg limitation.

The objective of this experiment was to evaluate the influence of copper supplementation in diets varying in amino acid (AA) density on growth performance, apparent metabolizable energy (AMEn), apparent ileal nutrient digestibility (AID), and plasma carotenoids in broilers infected with Eimeria acervulina. Ross 308 male broilers (480 total) were housed in battery cages and allotted to 8 experimental treatments in a factorial arrangement of 2 dietary AA densities [1.00% (LAA) or 1.20% (HAA) digestible Lys], 2 supplemental copper concentrations (zero or 116 mg/kg), and 2 E. acervulina infection states (uninfected or infected). Essential AA ratios relative to digestible Lys were similar in both the LAA and HAA diets, and copper was provided by 200 mg/kg of tribasic copper chloride (58% copper). Chicks received experimental diets from 2 to 21 d post hatch and 6 replicate cages of 10 birds per cage were assigned to each treatment. Broilers were inoculated with zero or 6.3 × 105 sporulated E. acervulina oocysts at 15 d and blood and ileal digesta were collected at 21 days. From 2 to 15 d, body weight gain and G:F of broilers were improved (P 0.05) with increasing AA density, and an AA density × copper interaction was observed (P 0.05) for feed intake. Eimeria infection reduced (P 0.05) plasma carotenoids, growth performance, dietary AMEn, and AID of organic matter, nitrogen, and total AA. There were no interactive effects of dietary treatments with E. acervulina infection on broiler growth performance or dietary AMEn. An AA density × copper supplementation interaction was observed (P 0.05) for AID of total AA, whereby copper supplementation increased AID of total AA for birds fed the LAA diet and decreased AID of total AA for birds fed the HAA diet. In summary, E. acervulina-induced reductions in nutrient digestibility were dependent on dietary copper and AA status, but changes in digestibility had minimal impact on growth performance of broilers during the E. acervulina infection period.

Human-grade dog foods are now available and increasing in popularity, but little research has been conducted to test the digestibility of these foods. The objective of this experiment was to determine the true nutrient and amino acid (AA) digestibilities of human-grade ingredient-based dog foods using the precision-fed cecectomized rooster assay. Six commercial dog foods were tested, including the Beef & Russet Potato (BRP), Chicken & White Rice (CWR), Fish & Sweet Potato (FSP), Lamb & Brown Rice (LBR), Turkey & Whole Wheat Macaroni (TWM) and Venison & Squash (VSR) formulas provided by Just Food For Dogs (Irvine, CA). Before analysis, all diets were lyophilized and ground. A precision-fed rooster assay utilizing cecectomized roosters was conducted to determine the true nutrient digestibility and standardized AA digestibilities of the diets tested. Conventional roosters were used to determine the nitrogen-corrected total metabolizable energy (TMEn) of the diets. All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. The substrates and rooster excreta were analyzed for macronutrient profile and AA composition. All data were analyzed using the Mixed Models procedure of SAS 9.4. In general, all diets tested were highly digestible. Dry matter digestibility was similar among CWR, LBR and TWR diets, and greater (P < 0.0001) than that of FSP and VSR diets. Organic matter digestibility was highest (P = 0.0002) for CWR and lowest (P = 0.0002) for VSR. TMEn value was highest for BRP. For the majority of indispensable AA, digestibilities were greater than 85%, with some being greater than 90%. Although statistical differences were observed among diets, they all performed very well. The diets tested had very high AA digestibilities, being digested at levels exceeding that usually observed with extruded diets.

Diet is known to affect rumen growth and development. Calves fed an all-liquid diet have smaller and less developed rumens and a decreased ability to absorb volatile fatty acids (VFA) compared to calves fed both liquid and dry feed. However, it is unknown how rumens respond when challenged with a defined concentration of VFA. The objective of this study was to assess the effects of 2 different feeding programs on VFA absorption in preweaned calves. Neonatal Holstein bull calves were individually housed and randomly assigned to 1 of 2 diets. The diets were milk replacer only (MRO; n = 5) or milk replacer with starter (MRS; n = 6). Diets were isoenergetic (3.87 ± 0.06 Mcal of metabolizable energy per day) and isonitrogenous (0.17 ± 0.003 kg/d of apparent digestible protein). Milk replacer was 22% crude protein, 21.5% fat (dry matter basis). The textured calf starter was 21.5% crude protein (dry matter basis). Feed and ad libitum water intakes were recorded daily. Calves were exposed to a defined concentration of VFA buffer (acetate 143 mM, propionate 100 mM, butyrate 40.5 mM) 6 h before euthanasia on d 43 ± 1. Rumen fluid samples were obtained every 15 to 30 min for 6 h to measure the rate of VFA absorption. Rumen tissues were obtained from the ventral sac region and processed for morphological and immunohistochemical analyses of the VFA transporters monocarboxylate transporter 1 (MCT1) and 4 (MCT4). Body growth did not differ between diets, but empty reticulorumens were heavier in MRS than MRO calves (0.67 vs. 0.39 ± 0.04 kg) and MRS calves had larger papillae areas (0.76 vs. 15 ± 0.08 mm2). We observed no differences between diets in terms of the abundance of MCT1 and MCT4 per unit area. These results indicate that the extrapolated increase in total abundance of MCT1 or MCT4 in MRS calves was not due to increased transporter density per unit area. Modeled VFA absorption metrics (flux, mmol/h, or 6 h absorbed VFA in mmol) were not different across diets. These results demonstrate that the form of calfhood diet, whether solely MR or MR and starter, does not alter VFA absorption capacity when the rumen is exposed to a defined concentration of VFA at 6 wk of age.

An experiment was conducted to determine the effect of supplementing diets fed to growing pigs with fat sources differing in their composition of fatty acids on the apparent total tract digestibility (ATTD) of minerals. A diet based on corn, potato protein isolate, and 7% sucrose was formulated. Five additional diets that were similar to the previous diet with the exception that sucrose was replaced by 7% tallow, choice white grease, palm oil, corn oil, or soybean oil were also formulated. Diets were formulated to contain 0.70% Ca and 0.33% standardized total tract digestible P. Growing barrows ( = 60; 15.99 ± 1.48 kg initial BW) were allotted to a randomized complete block design with 2 blocks of 30 pigs, 6 dietary treatments, and 10 replicate pigs per treatment. Experimental diets were provided for 12 d with the initial 5 d being the adaptation period. Total feces were collected for a 5-d collection period using the marker-to-marker approach, and the ATTD of minerals, ether extract, and acid hydrolyzed ether extract was calculated for all diets. Digestibility of DM was greater ( < 0.05) in the diet containing soybean oil compared with the diet containing choice white grease or the basal diet, with all other diets being intermediate. The ATTD of Ca, S, and P was greater ( < 0.05) for pigs fed diets containing soybean oil, corn oil, palm oil, or tallow than for pigs fed the basal diet or the diet containing choice white grease. The ATTD of Mg, Zn, Mn, Na, and K were not different among dietary treatments. The ATTD of ether extract was greater ( < 0.05) in diets containing palm oil, corn oil, or soybean oil compared with the diet containing choice white grease, and the ATTD of acid hydrolyzed ether extract in the diet containing soybean oil was also greater ( < 0.05) than in the diet containing choice white grease. In conclusion, supplementation of a basal diet with tallow, palm oil, corn oil, or soybean oil may increase the ATTD of some macrominerals, but that appears not to be the case if choice white grease is used. There was no evidence of negative effects of the fat sources used in this experiment on the ATTD of any minerals.

SUMMARY Nutritional differences due to variety, source, and effects of heat processing on cowpeas (Vigna unguiculata) were assessed. The precision-fed cecectomized rooster assay was used to determine amino acid digestibility and TME of cowpeas. Mozambican cowpea (nhemba) treatments included either raw or roasted, whereas those (black-eyed beans) sourced from the United States were raw, roasted, or extruded. Crude protein content on a DM basis was similar for raw nhemba (296 g/kg) in comparison to raw black-eyed beans (299 g/kg). Raw nhemba had slightly higher amino acid content (except tryptophan) than raw black-eyed beans. The level of trypsin inhibitors of nhemba was 3 times higher than black-eyed beans (6,700 vs 2,200 TIU/g). Heat treatment generally had no effect on amino acid concentration except for lysine, which was reduced in both beans by heat. Additionally, all heat treatments reduced the concentration of trypsin inhibitors to below 2,000 TIU/g. Amino acid digestibility for the nhemba cowpeas was lower than for the black-eyed cowpeas except for tryptophan. Roasting had no effect on amino acid digestibility in black-eyed beans, but increased digestibility of several amino acids in nhemba cowpeas, and the average increase was 3.4 percentage units. The TMEn of raw nhemba cowpeas was significantly increased (2,806 vs 3,347 kcal/kg DM) by roasting and the TMEn of raw black-eyed cowpeas was significantly increased by extrusion (3,164 vs 3,535 kcal/kilogram DM).

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.

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 3,890 kcal/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 3,372 kcal/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.

Three slope-ratio precision-fed rooster assays were conducted wherein roosters were precision-fed 0, 5, 10, 15, or 20% (levels varied among experiments) refined soy oil, refined corn oil (RCO), poultry fat, crude soy oil, crude corn oil, palm oil, vegetable blend acid oil 1 and 2, soy acid oil, tallow, or choice white grease as part of a ground corn diet. Multiple regression slope-ratio analysis of nitrogen-corrected true metabolizable energy regressed on dietary fat level was used to estimate relative metabolizable energy (RME) values. The RME values were calculated as the regression coefficient of the test lipid divided by the regression coefficient of the reference refined soy oil or RCO (set at 100%). The results of the rooster experiments indicated that only the RME values of palm oil 1 (83%) and tallow (74%) were significantly lower (P < 0.05) than that of refined soy oil or RCO. It was observed that the differences among fat sources were often greater at the higher inclusion levels of 15 and 20%. In addition to the slope-ratio precision-fed rooster assays, a limit-fed broiler chicken growth assay was conducted. The broilers were limit-fed to 70% of their expected daily intake from 11 to 20 d of age, and four lipid sources (RCO, palm oil 2, choice white grease, and vegetable blend acid oil 2) were tested at 0, 5, and 10% inclusion levels. Multiple regression slope-ratio analysis of body weight gain regressed on dietary fat intake indicated that the relative bioavailability values (RBV) of palm oil 2 (80%) and choice white grease (85%) were significantly lower than the 100% for RCO (P < 0.05), whereas the RBV of the vegetable blend acid oil 2 (93%) was not significantly different from 100%. In general, both the precision-fed rooster assay and the limit-fed broiler chicken assay were able to detect differences in RME or RBV among lipids; however, using higher inclusion rates of 15 or 20% of the lipids may increase sensitivity of the rooster assay.

Tumor protein 63 (p63) is a nuclear antigen found in basal epithelial cells. To date, 10 isoforms of p63 have been identified, falling into 2 major groups identified by presence or absence of an N-terminal transactivation domain (TAp63 and ΔNp63, respectively). Literature suggests that ΔNp63 is the predominant form expressed in basal epithelial cells and myoepithelial cells (MYEC). The mouse anti-p63 antibody, clone 4B1E12, has been used as a specific nuclear marker for bovine MYEC. Unfortunately, this antibody is no longer commercially available. A new mouse monoclonal antibody, clone BC28, specific to ΔNp63 (designated p40) has been developed. We hypothesized that the p40 antibody would be an appropriate substitution as a MYEC and epithelial basal cell marker. An array of archived formalin-fixed, paraffin-embedded bovine tissues were subjected to immunohistochemical staining for either p40 or p63, with a subset being dual stained for direct comparison. Positive staining for p40 and p63 was observed in serial sections of mammary, skin, rumen, salivary gland, ureter, and bladder. As predicted, negative staining for p40 and p63 was observed in testis and intestine. Dual staining for p40 and p63 in calf mammary (n = 4), lactating mammary (n = 4), rumen (n = 4), and skin (n = 4) showed nearly 100% agreement. Thus, we established that the mouse monoclonal antibody, clone BC28, is a suitable replacement for anti-p63, clone 4B1E12, as a marker of MYEC and basal epithelial cells in bovine tissues.

The objective of this study was to evaluate the nutritional value of Glutenol, a new coproduct of the ethanol industry. Glutenol was produced by Quality Technology International, Elgin, IL, in a modified wet-milling plant using a hybrid process, NextGenFrac, which fractionates the corn kernel components prior to fermentation without the use of sulfur dioxide. Glutenol was analyzed to contain 52.3% CP, 1.7% Met + Cys, 1.32% Lys, 1.69% Thr, and 2.23% Val on a DM basis. Two precision-fed rooster assays with conventional and cecectomized roosters were conducted to determine TMEn and standardized digestibility of amino acids (AA), respectively. The TMEn of Glutenol was determined to be 3,256 kcal/kg DM. Standardized digestibility values for Lys, Met, Cys, Thr, and Val were 80.1%, 90.4%, 80.1%, 74.1%, 81.1%, and 84.9%, respectively. In addition, a 3-wk broiler chick assay was conducted with increasing levels of dietary Glutenol. Diet 1 was a standard corn/soybean meal diet with 0% Glutenol. Diets 2, 3, and 4 had increasing levels of Glutenol at 4%, 8%, and 12%, respectively. Diets were fed from 3 to 22 d post-hatch and all diets were formulated to be equal in TMEn and digestible AA. Weight gain, feed intake, and gain/feed ratio were measured. No differences in growth performance were observed among dietary treatments. In conclusion, Glutenol can be fed up to at least 12% in the diet of broiler chickens if diets are formulated to be equal in ME and digestible AA.

Plant-based proteins are under-utilized as alternative protein sources in the pet food industry. Novel plant protein sources may alleviate symptoms associated with food sensitivities, and satisfy the growing consumer demand for vegan and vegetarian pet foods. However, there is little information regarding the chemical composition and suitability of these ingredients for pet nutrition. The objective of this study was to determine the macronutrient composition, standardized amino acid and nutrient digestibility of 14 novel, plant-based, protein ingredients. A variety of pulses (lentils, garbanzo beans), legumes (yellow peas, navy beans, black beans), and protein concentrates (pea, potato, faba bean, soy) were analyzed for dry matter, ash and organic matter (AOAC, 2006), crude protein (AOAC, 2006), gross energy (bomb calorimetry), acid hydrolyzed fat (AACC, 1983; Budde, 1952), and total dietary fiber (Prosky et al., 1992). Precision-fed rooster assays were conducted using cecectomized, Single Comb White Leghorn roosters (n=4/trt). The roosters were precision-fed 30g of a 1:1 ratio of an ingredient and corn mixture. Excreta were collected after 48h, freeze-dried, and analyzed for dry matter, organic matter, gross energy, and total nitrogen. Complete amino acid profiles (AOAC, 2007) were determined. For the protein concentrate sources, there were no significant differences in the digestibility of essential or non-essential amino acids, except methionine, which was lower (P < 0.05) in faba bean protein concentrate. The legumes follow similar trends for essential amino acids, but have significant differences (P < 0.05) in the digestibility of cysteine and tyrosine. All amino acids, with the exception of methionine in the legume sources, met or exceeded the minimal requirement set by the NRC (2006) for dogs and cats. It can be concluded that plant-based protein sources have the potential to become viable, novel, protein sources in canine and feline diets.

An experiment was conducted to evaluate effects of 2 high-protein canola meals (canola meal A [CMA]: 45.69% CP and canola meal B [CMB]: 46.97% CP) and a conventional canola meal (CM-CV: 35.10% CP) on growth performance, organ weights, bone ash, and blood parameters of weanling pigs. Inclusion rates of canola meal (CM) in the diets were 10, 20, 30, or 40% for CMA and CM-CV, whereas inclusions were 10, 20, or 30% for CMB. A control diet containing no CM was also formulated. Therefore, 12 diets were used in this experiment. A total of 420 pigs (initial BW: 9.8 ± 1.1 kg) were divided into 3 blocks and randomly allotted to 1 of the 12 diets with 8 replicate pens per treatment and 4 or 5 pigs per pen. The ADG, ADFI, and G:F were calculated, and at the conclusion of the experiment, 1 pig in each pen was euthanized to allow measurements of organ weights, collection of blood, and collection of the third and fourth metacarpals from the left foot. Results indicate that ADFI was linearly (P < 0.05) decreased if inclusion of CMA, CMB, or CM-CV was increased. Average daily gain for pigs fed CMA tended to increase quadratically with the maximum response observed at 10 or 20% CM inclusion in the diet ( P= 0.06). However, G:F was linearly (P < 0.05) increased by adding CMA or CM-CV to the diets. Liver weights were also linearly (P < 0.05) increased if pigs were fed diets containing CMB, but kidney weights were linearly (P < 0.05) decreased by the addition of CM-CV to the diets. Thyroid gland weights increased linearly (P < 0.05) for pigs fed diets containing CMA. No differences were observed in heart and bone weights if CM was added to the diets. Addition of any of the 3 CM linearly (P < 0.05) increased bone ash percentage in the metacarpals. Inclusion of CMA or CM-CV linearly (P < 0.05) decreased concentrations of serum triiodothyronine, and the inclusion of CMA also linearly (P < 0.05) decreased serum thyroxine concentrations. No differences were observed for complete blood counts or blood urea nitrogen if CM was added to the diets. In conclusion, up to 20% high-protein CM or CM-CV may be included in diets for weanling pigs from 2 wk postweaning without reducing growth performance or negatively affecting organ, bone, or blood parameters. In some instances, it may also be possible to use greater inclusion rates.

Sixteen meat and bone meal (MBM) samples were obtained and selected from various company plants to provide a wide range in pepsin nitrogen digestibility values. Pepsin digestibility was determined using either 0.02 or 0.002% pepsin. Amino acid (AA) digestibility of the 16 MBM samples was then determined using a precision-fed cecectomized rooster assay. The 0.02% pepsin digestibility values were numerically higher than the 0.002% pepsin values. The values varied from 77 to 93% for 0.02% pepsin and from 67 to 91% for 0.002% pepsin. The rooster AA digestibility results showed a wide range of values among MBM samples mostly due to the 4 samples having lowest and highest AA digestibility. A precision-fed broiler chick ileal AA digestibility assay confirmed that there were large differences in AA digestibility among the MBM samples having the lowest and highest rooster digestibility values. Correlation analyses between pepsin and AA digestibility values showed that the correlation values (r) were highly significant (P0.0001) for all AA when all 16 MBM samples were included in the analysis. However, when the MBM samples with the 2 lowest and the 2 highest rooster digestibility values were not included in the correlation analyses, the correlation coefficient values (r) were generally very low and not significant (P0.05). The results indicated that the pepsin nitrogen digestibility assay is only useful for detecting large differences in AA digestibility among MBM. There also was no advantage for using 0.02 versus 0.002% pepsin.

Megasphaera elsdenii is a bacterial species of the rumen that can utilize lactate to produce butyrate, a key volatile fatty acid often implicated in driving calf rumen development. Because lactate is abundant in the rumen of young calves, administration of M. elsdenii to increase butyrate production and thus promote calf rumen development is an appealing possibility. The main objective of this study was to determine whether M. elsdenii administration to calves via oral drench at 14 d of age affected its long-term establishment at 70 d postadministration. Ruminal volatile fatty acid and lactate profiles and blood glucose and β-hydroxybutyrate concentrations were also examined to determine potential influence on rumen metabolism. Six neonatal Holstein heifer calves were blocked on d 1 by body weight (41.3 ± 1.8 kg) and total serum protein (5.23 ± 0.16 g/dL) and assigned to either the M. elsdenii (n = 3) or control (n = 3) treatment groups. On d 14, calves in the M. elsdenii group orally received 25 mL of a commercially available M. elsdenii suspension, whereas calves in the control group received 25 mL of the same product that had been autoclaved. Rumen contents and blood samples were collected weekly from each animal until 84 d of age. The oral administration of M. elsdenii at 14 d did not increase the abundance of M. elsdenii 70 d postdosing, alter rumen fermentation, or change blood metabolites associated with butyrate. These results suggest that a single administration of the M. elsdenii probiotic may not affect the rumen establishment of the organism.

Whole prey diets are commonly used in the zoo and home setting for captive exotic and domestic cats, respectively. Despite their increase in popularity, nutrient digestibility of such diets has been poorly studied. In this study, the precision-fed cecectomized rooster assay was used to determine the protein quality and nitrogen-corrected true ME (TMEn) of 17 whole prey samples (mice [1 to 2 , 10 to 13 , 21 to 25 , 30 to 40 , and 150 to 180 d old], rats [1 to 4, 10 to 13, 21 to 25, 32 to 42, and >60 d old], rabbits [stillborn, 30 to 45 d old, and >65 d old], chicken [1 to 3 d old], and quail [1 to 3, 21 to 40, and >60 d old]) and 2 ground poultry-based products (chicken and duck). Amino acid score (AAS) and protein digestibility corrected AAS (PDCAAS) were calculated using the nutrient profile recommendations for domestic cat food as a reference value (AAFCO, 2012). Average individual indispensable AA (IAA) and total IAA (TIAA) digestibility coefficients were variable anddepended on AA (84 to 94% TIAA, 85 to 95% Arg, 87 to 96% His, 82 to 92% Ile, 84 to 94% Leu, 85 to 93% Lys, 89 to 97% Met, 83 to 94% Phe, 80 to 95% Thr, 84 to 94% Trp, and 80 to 93% Val) and sample. For a majority of the whole prey items, AA concentrations were greater than the Association of American Feed Control Officials ( AAFCO: , 2012) domestic cat nutrient profile recommendations for growth and reproduction and adult maintenance; however, some whole prey had AA concentrations below the AAFCO (2012) recommendations: Met + Cys (1.10% DM) in ground duck (1.06% DM) and taurine (Tau; 0.20% DM) in 30-to-45- and >65-d-old rabbits (0.01 and 0.10% DM, respectively), 150-to-180-d-old mice (0.18% DM), and ground duck (0.15% DM). The TMEn (3.76 to 6.44 kcal/g DM) expressed as the percent of GE (i.e., TMEn/GE) ranged from 66 to 85%, demonstrating how variable the digestibility of these items may be and justifying more research in this area. Both Met and Tau are commonly added to commercial pet foods, so supplements are readily available to address potential deficiencies and improve protein quality. A direct comparison of the ME of whole prey items by in vivo feline and rooster experiments is needed.

The objective of this study was to compare two in vivo methods using pigs and roosters and an in vitro method for determining the caloric value of four fiber sources (i.e., two resistant starches (RS 60 and RS 75), soluble corn fiber (SCF 70), and pullulan). Metabolizable energy (ME) in pigs and true metabolizable energy (TMEn) in roosters were determined by using 72 barrows and 24 roosters, respectively. A two-step in vitro procedure was used to quantify monosaccharides released. Results of the two in vivo experiments corresponded well with RS 75 having the least caloric value (7.55 MJ/kg in pigs; 6.19 MJ/kg in roosters) and pullulan having the greatest caloric value (12.21 MJ/kg in pigs; 13.94 MJ/kg in roosters). The caloric values for all the fiber ingredients were less (P < 0.05) than in MD both in pigs and in roosters. Despite some limitations, results of the in vitro procedure corresponded well with the in vivo experiments where the concentration of glucose hydrolyzed from RS 60, RS 75, and SCF 70, but not pullulan, was less (P < 0.05) than the concentration of glucose hydrolyzed from MD. However, the greatest accuracy was obtained in the in vivo experiments.

a b s t r a c t Four digestibility trials using broilers from 12 to 21 d or 7 to 21 d of age were conducted to evaluate the nutrient digestibility responses of two enzyme combinations when supple- mented to maize-soybean meal (SBM) based diets without (trials 1 and 3) or with (trials 2 and 4) 70 or 100 g/kg maize dried distillers grain with solubles (DDGS). Apparent ileal digestible energy (AIDE), apparent ileal digestibility (AID) of amino acids (AA), total tract apparent retention (TTAR) of nitrogen (N) and N-corrected apparent metabolisable energy (AMEn) were assessed. In each trial, a control diet and the control diet supplemented with an enzyme complex containing xylanase and amylase (XA) or one containing protease, xylanase and amylase (PXA) were tested. Trials 1 and 2 had six replicate cages per treat- ment, with six birds per cage; and trials 3 and 4 had eight replicate cages per treatment, with five birds per cage. Data were analysed by ANOVA for each trial, as well as a combined dataset, which model included the main effects of maize-DDGS inclusion, dietary enzyme and trial site and all two-way interactions. Across trials, both XA (13.61 MJ/kg) and PXA (13.70 MJ/kg) increased the AIDE (P

Our objective was to evaluate raw meat diets for captive exotic and domestic carnivores containing traditional and alternative raw meat sources, specifically, beef trimmings, bison trimmings, elk muscle meat, and horse trimmings. We aimed to examine diet composition and protein quality; apparent total tract energy and macronutrient digestibility in domestic cats, African wildcats, jaguars, and Malayan tigers; and ME and fecal fermentative end-products in domestic cats. Because of variation in the meat sources, dietary proximate, AA, and long-chain fatty acid composition were variable. Our analyses indicated that all diets had essential fatty acid deficiencies, and the elk diet (i.e., trimmed muscle meat) was deficient in total fat. Standardized AA digestibilities measured using the cecectomized rooster assay were high (>87%). Using the NRC minimum requirements for the growth of kittens, the first limiting AA of all diets was the combined requirement of Met and Cys (AA score: 81 to 95; protein digestibility corrected AA score: 75 to 90). All diets were highly digestible (88 to 89% OM digestibility). There was no effect of diet or felid species on DM (85 to 87%), OM, and GE (90 to 91%) digestibilities. Apparent CP digestibility was greater (P≤0.05) in cats fed elk (97%) compared with those fed bison (96%), and greater (P≤0.05) in wildcats (97%) and domestic cats (97%) compared with tigers (95%). The diet and species interaction (P≤0.05) was observed for apparent fat digestibility. In domestic cats, the fresh fecal pH and proportions of acetate and butyrate were altered (P≤0.05) due to diet. Diet also affected (P≤0.05) fresh fecal concentrations of total branched-chain fatty acids, valerate, and Lactobacillus genus. In conclusion, although the raw meat diets were highly digestible, because of variation in raw meat sources the nutrient composition of the diets was variable. Thus, compositional analysis of raw meat sources is necessary for proper diet formulation. The types of meat commonly used in raw meat diets may be deficient in total fat (trimmed muscle meat) and essential fatty acids (trimmings and muscle meats). Additionally, differences in raw meat source nutrient composition and digestibility affect the beneficial and putrefactive fermentative end-products found in feces.

The objective of this study was to determine standardized AA digestibility of corn, corn gluten meal, and 3 distillers dried grains with solubles (DDGS) using the precision-fed cecectomized rooster assay (PFR), the standardized ileal AA broiler chicken assay (SIAAD), and a newly developed precision-fed ileal broiler chicken 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 ad libitum fed a semi-purified diet containing the feed samples as the sole source of protein from 17 to 21 d, with ileal digesta collected at 21 d. For the PFC, 22-d-old broiler chickens were precision-fed 10 g of feed and ileal digesta were collected at 4 h postfeeding. For corn, the PFC yielded significantly higher digestibilities than the SIAAD and PFR for several AA. For corn gluten meal, the PFR yielded significantly higher values than the PFC for the majority of the AA, with the SIAAD yielding intermediate values. When 3 DDGS samples were evaluated, the PFR produced higher digestibilities than the PFC for all 3 DDGS samples for most of the AA. When comparing the PFR and the SIAAD, the PFR yielded higher values than the SIAAD for one DDGS, whereas there was generally no significant difference between these 2 methods for the other 2 DDGS samples. The results of this study indicate there were differences among standardized AA digestibility values for the PFR, SIAAD, and PFC in some instances. The differences among methods were not consistent; however, the PFR yielded higher digestibility values than the PFC for 4 of the 5 ingredient samples.

A wide variety of animal protein-based ingredients is commonly used in the pet food products. The raw ingredients and processing procedures used may greatly affect protein quality. Testing the quality of alternative protein sources is necessary and contributes to the sustainability of pet foods. The objective of this study was to test the chemical composition of 8 protein sources intended for use in dog and cat foods (calamari meal, pork peptone, alligator meal, lamb meal, venison meal, chicken meal, and 2 duck meals), and evaluate their true nutrient digestibility and nitrogen-corrected true ME (TMEn) using the precision-fed cecectomized rooster assay. Calamari meal and pork peptone had lower ash (4.4 and 3.6% of DM, respectively) but greater CP (88.1 and 80.5% of DM, respectively) and either greater or similar GE (5.6 and 5.3 kcal/g of DM, respectively) compared with alligator, lamb, venison, chicken, and duck meals (11.8 to 24.5% ash, 58.7 to 65.9% CP, and 4.6 to 5.3 kcal GE/g). Acid-hydrolyzed fat (AHF) was lower in calamari meal (8.7% of DM) compared with the other proteins tested (15.5-22.1% of DM). True nutrient digestibility was variable among the protein sources (52 to 79% of DM, 60 to 83% of OM, 78 to 92% of AHF, and 70 to 89% of GE) with pork peptone having the highest DM, AHF, and GE digestibility and calamari meal having the highest OM digestibility. True indispensable AA digestibility was highest for calamari meal, with all AA having a digestibility greater than 90%. Except for histidine, all indispensable AA had a digestibility over 85% for pork peptone. In contrast, true indispensable AA digestibility was lowest for lamb meal, with histidine having digestibility less than 70% and the other entire indispensable AA having digestibility between 72 and 88%. The TMEn of calamari meal (4.82 kcal/g DM and 86.9% of GE) was greater ( < 0.05) than the other protein sources. The lamb meal had the lowest TMEn value (3.12 kcal/g DM and 66.9% of GE), with others being intermediate (3.46-4.09 kcal/g DM and 71.2-77.9% of GE). This study demonstrates the considerable variability that exists not only in the chemical composition but also in the true nutrient digestibility among protein sources intended for use in dog and cat foods and justifies further in vivo testing of novel protein sources.

Two experiments were conducted to evaluate the influence of Eimeria acervulina infection on growth performance, plasma carotenoids, and intestinal cytokine responses of broilers fed low crude protein (LCP) diets with reduced concentrations of selected amino acids (AA). Experiment 1 was conducted to validate a dietary formulation approach in which broilers were fed 1 of 5 diets including a 19.0% CP corn-soybean meal based (CSBM) diet, a LCP control diet (16.7% CP) that matched the AA profile of the CSBM diet, and 3 LCP diets with 30% reductions in standardized ileal digestible concentrations of TSAA, Lys, or Thr from 14 to 23 d post-hatch. Body weight gain and G:F were greatest (P0.05) and similar for broilers fed the CSBM and LCP control diets, whereas reductions in Thr, TSAA, and Lys each decreased (P0.05) G:F of broilers. In Experiment 2, birds were allotted to 18 treatment groups in a factorial arrangement of 9 dietary treatments × 2 infection states. Dietary treatments included a LCP control diet similar to that fed in Experiment 1 and 8 LCP diets with 40% individual reductions in TSAA, Lys, Thr, Val, Ile, Arg, Phe + Tyr, or Gly + Ser. Broilers received experimental diets from 10 d to 28 d post-hatch and were inoculated with 0 or 4.0 × 10

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.

An experiment was conducted to evaluate growth performance, apparent ileal digestibility (AID) of amino acids, and plasma concentrations of amino acids, carotenoids, and α1-acid glycoprotein, an acute-phase protein, in broilers inoculated with graded doses of E. acervulina oocysts. Ross 308 male broilers (400 total) were housed in battery cages from 1 to 21 d post-hatch and received common corn-soybean meal-based diets throughout the experiment. At 9 d post-hatch, birds were individually weighed and allotted to 4 treatment groups with 10 replicate cages of 10 birds per cage. At 15 d post-hatch, all birds were inoculated with 1 mL of distilled water that contained 0, 2.5 × 10(5), 5.0 × 10(5), or 1.0 × 10(6) sporulated E. acervulina oocysts. At 21 d, birds were euthanized for collection of blood and ileal digesta. Body weight gain and feed efficiency decreased linearly (P 0.05) with increasing E. acervulina dose. With the exception of Trp and Gly, AID values decreased (P 0.05) linearly or quadratically for all amino acids by an average of 2.6 percentage units for birds inoculated with 1.0 × 10(6) oocysts compared with uninfected birds. Infection with E. acervulina caused a quadratic decrease (P 0.05) in plasma carotenoid concentrations. Plasma concentrations of Arg and Tyr decreased linearly (P 0.05) with increasing E. acervulina inoculation dose and plasma Gln and Asn decreased quadratically (P 0.01). Linear increases (P 0.05) were observed for plasma Lys, Leu, Ile, Val, Pro, and Orn as E. acervulina inoculation dose increased. Plasma α1-acid glycoprotein of broilers was not influenced (P 0.05) by E. acervulina infection. In conclusion, E. acervulina challenge adversely impacted growth performance, plasma carotenoids, and AID of amino acids in a dose-dependent manner. However, plasma amino acid responses to graded E. acervulina inoculation doses varied considerably among amino acids. Thus, these results indicated that alterations in amino acid metabolism caused by E. acervulina infection extended beyond reduced amino acid digestibility.

Accurate estimation of ileal endogenous amino acid (EAA) losses is important when formulating diets on a standardized ileal digestible amino acid basis. In addition to the undigested and unabsorbed amino acids of dietary origin, amino acids of endogenous origin, which can be basal or diet specific, are found in digesta. The improvement in the techniques used in amino acid analysis as well as a shift from sampling excreta to ileal digesta has resulted in more accurate amino acid digestibility coefficients. Despite this, however, it is important to determine the amino acids in the digesta that are of endogenous origin. Although the need for standardization and its associated advantages is still subject to debate, it is important to evaluate how values from various methodologies compare. Several methods have been used to estimate ileal EAA flow. The classical methods, including the regression method, the use of nitrogen-free diet (NFD), and the fasted cecectomized rooster method, are the most widely used. The criticisms with the last 2 methods are that birds are not in a normal physiological state and the ileal EAA flow is, therefore, underestimated. Different methods have resulted in different endogenous flow estimates, with the NFD method having the lowest values when compared with flows from the regression and highly digestible protein methods. In addition to the influence of methods on ileal EAA flows, the influence of the age of the birds on flow is important. Data on EAA losses are copious in the literature; however, variation in data across and within laboratories calls for investigation of factors contributing to the variation. This review compares results from different methods and examines the issue of repeatability and consistency of EAA losses data from different laboratories. Finally, composition of an NFD for estimating EAA losses is proposed.

SUMMARY The objective of this study was to evaluate the effect of a mixture of carvacrol, cinnamaldehyde, and capsicum oleoresin (XT, Pancosma S.A., Geneva, Switzerland) on the MEn of cornsoybean meal diets for broilers (experiment 1) and to confirm the energy effect in a growth performance trial (experiment 2). For experiment 1, 12 replicate groups of 5 chicks were assigned to each of the 4 treatments in a 2 × 2 factorial design. Factor 1 was diet type [corn-soybean meal or corn-soybean meal with 10% corn distillers dried grains with solubles (DDGS)]. Factor 2 was XT (0 vs. 100 mg/kg of XT). Diets were fed from 1 to 22 d. For experiment 2, chicks were fed a corn-soybean meal diet (no DDGS) from 9 to 34 d of age. Two factors were again organized in a complete 2 × 2 factorial design. Factor 1 was dietary MEn content (3,000 vs. 2,950 kcal of MEn/kg), and factor 2 was XT (0 vs. 100 mg of XT/kg). For experiment 1, from d 1 to 8, XT significantly increased BW gain (P < 0.05). The XT also significantly increased MEn content at 22 d, with the increase being 68 kcal/kg for the corn-soybean meal diet with no DDGS. The 90% CI for the 68 kcal/kg value was 50 to 86 kcal/kg. The latter is the reason the value of 50 kcal/kg was selected as the energy difference between diets in experiment 2. The decrease in MEn from 3,000 to 2,950 kcal/kg significantly depressed BW gain (2.4%) and G:F (2.1%). Conversely, XT significantly increased BW gain (2.4%) and G:F (2.3%). We observed that a 100 mg/kg mixture of carvacrol, cinnamaldehyde, and capsicum oleoresin increased the dietary MEn of the corn-soybean meal diet. The MEn value of 50 kcal/kg for 100 mg of XT/kg corresponded to the lower limit of the 90% CI and was confirmed in a growth performance trial.

The objective of this research was to measure in vitro hydrolytic digestion characteristics, glycemic and insulinemic responses, and true metabolizable energy (TMEn) content of select soluble fiber dextrins (SFDs) and pullulans. The SFDs were derived either from tapioca starch or from corn starch. The pullulans were of low, intermediate, and high molecular weight. Soluble fiber dextrins varied in digestibility, with all substrates resulting in low to intermediate in vitro monosaccharide digestion. Pullulans were nearly completely hydrolyzed after simulated hydrolytic digestion. The glycemic response with dogs varied widely among SFDs, with all but one SFD substrate having lower glycemic response than maltodextrin (Malt). The pullulans all resulted in low glycemic values. Lower relative insulinemic responses (RIR) compared to the Malt control were noted for all SFDs and pullulans. True metabolizable energy (TMEn) values for SFDs obtained using roosters were lower than for Malt, with tapioca-based SFDs having numerically higher values than corn-based SFDs. Pullulans resulted in higher TMEn values than did SFDs. Soluble fiber dextrins and pullulans may be suitable candidates for reduced calorie and glycemic foodstuffs.