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

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

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

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?

Insect meals are novel and potentially sustainable protein sources. The objectives of this study were to determine the chemical composition and standardized amino acid digestibility using the cecectomized rooster model of three selected insect meals (i.e., speckled cockroach [SC], Madagascar hissing cockroach [MC], and superworm [SW]) and to determine the effects of these insect meals on food intake, apparent total tract digestibility (ATTD) of macronutrients, fecal scores, and metabolites of adult cats fed insect- or chicken-based retorted diets. This study consisted of a complete randomized design, with 28 adult cats randomly assigned to one of the four experimental retorted diets: Control (chicken-based diet), SC diet, MC diet, or SW diet. All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee. All diets were formulated to be complete and balanced and meet or exceed the nutritional requirements of adult cats. The experimental period was 28 d, with the first 7 d allotted for diet adaptation. The total fecal collection was completed during the last 4 d of the experimental period. On day 21, a fresh fecal sample from each cat was collected for the determination of fecal metabolites and microbiota. Food was offered twice daily to maintain body weight and body condition score. Among the three selected insect meals evaluated, oleic acid, palmitic acid, linoleic acid, and stearic acid were the most prevalent fatty acids. Branched-chain amino acids and arginine were the most preponderant indispensable amino acids in these insect meals. ATTD of dry matter, organic matter, acid-hydrolyzed fat, and crude protein did not differ among treatments (P 0.05), and all diets were well digested by the cats. Similarly, fecal scores did not differ among the treatments and were within ideal range. No differences (P 0.05) in fecal metabolite concentrations or microbiota diversity were observed among cats fed different experimental diets; only a few genera from Firmicutes and Bacteroidota phyla differ (P 0.05) in cats fed SW diet in contrast to other dietary treatments. In conclusion, the selected insect meals evaluated herein are rich in linoleic acid, an essential fatty acid for cats. Insect-based retorted diets led to comparable results to those achieved with a chicken-based retorted diet, suggesting that these novel protein sources might be adequate alternative ingredients in feline diets.Insect meals are novel and potentially sustainable protein sources. The objectives of this study were to determine the nutrient composition of speckled cockroach, Madagascar hissing cockroach, and superworm (SW) and to determine the effects of these insect meals on food intake, digestibility of macronutrients, fecal scores, metabolites, and microbiota of adult cats fed insect- or chicken-based wet pet foods. Among the three selected insect meals evaluated, oleic acid, palmitic acid, linoleic acid, and stearic acid were the most prevalent fatty acids. Branched-chain amino acids and arginine were the most preponderant indispensable amino acids in these insect meals. All diets were well digested by the cats with no differences observed on macronutrient digestibility. Similarly, fecal scores did not differ among the treatments and were within the ideal range. No differences in fecal metabolite concentrations were observed. Only a few genera from Firmicutes and Bacteroidota phyla differ in cats fed SW diet in contrast to other dietary treatments. Overall, the selected insect meals evaluated herein are rich in linoleic acid, an essential fatty acid for cats. Insect-based retorted diets led to comparable results to those achieved with a chicken-based retorted diet, suggesting that these novel protein sources might be adequate alternative ingredients in feline diets.

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.

There has been a quest for novel and alternative protein sources in pet nutrition due to product diversification, need for novel and single protein diets, and concerns with sustainability. However, limited information on chemical composition and amino acid (AA) digestibility of these ingredients are available. The novel protein sources tested are of aquatic and reptile species, and include fish slurry, white fish, spirulina, eel, salmon, and rattlesnake. We determined the chemical composition and applied the cecectomized rooster model to estimate standardized AA digestibility of these protein sources. The ingredients were further assessed by calculation of digestible indispensable amino acid scores (DIAAS-like). Dry matter values were similar across all proteins and ranged from 91.3% to 99.4%. Crude protein was least in salmon (43.5%) and greatest in fish slurry and spirulina (72.5% and 72.8%, respectively). Rattlesnake produced the least amount of total fat at 1.8% and eel produced the most at 32.3%. Standardized AA values were >80% for both dispensable and indispensable AA in all protein sources. For DIAAS-like calculations, reference proteins were based on nutrient profiles of the Association of American Feed Control officials (AAFCO) nutrient profile and the National Research Council (NRC) recommended allowances for adult dogs and cats at maintenance. Using these references, rattlesnake was low quality for both dogs and cats. Fish slurry and spirulina were observed to be high quality for dogs and cats using AAFCO references and high quality in only cats using NRC references. Using the NRC reference for dogs, fish slurry and spirulina were determined to be moderate quality because the first-limiting AA in fish slurry (tryptophan) was 78% and first-limiting AA in spirulina (methionine) was 63%. Scores < 100% but >50% are considered moderate quality according to the DIAAS method.

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

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

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.

A laying hen trial was conducted from 22 to 47 wk of age to determine the digestible lysine (DLYS) requirement of laying hens by using an increasing CP titration method. A total of 896 Lohmann LSL-Lite caged layers (22 wk of age) were allotted to 8 dietary treatments and each treatment had 8 replications of 14 hens. The first 7 experimental diets initially contained DLYS levels increasing from 0.565 to 0.980% with respective protein levels increasing from 13.8 to 21.7%. Dietary treatment 8 was a control diet which was calculated to contain 18.6% CP and 0.807% DLYS. These DLYS levels were reduced from 0.468 to 0.845% for diets 1 to 7 (0.688% for diet 8) at week 12 so that greater differences in production parameters could be obtained. Increasing DLYS levels had a significant (P0.05) effect on egg production, egg weight, egg mass, and feed efficiency. However, DLYS levels had no significant effect on egg component measurements such as percentage of yolk, white, and solids. Broken line regression, maximum of the quadratic polynomial (QP max) regression, and the intercept of the broken line and QP regressions were used to estimate the DLYS requirement. Broken line regression yielded the lowest requirement and QP max regression yielded the highest, with the intercept of the broken line and QP regressions yielding an intermediate requirement estimate. The DLYS requirements were consistently lower for egg production than for egg mass and feed efficiency. For egg mass and feed efficiency, DLYS requirements were 655 and 690, 817 and 866, and 706 and 778 mg/hen/d for the broken line, QP max, and the intercept of the broken line and QP regressions, respectively.

Bovine mastitis is a common and costly disease in the dairy industry and is known to negatively affect the amount of epithelium in nonlactating mammary glands. Despite this recognition, an understanding of the mechanisms contributing to reductions in epithelium is lacking. The objective of this study was to evaluate cellular apoptosis and proliferation in uninfected and Staphylococcus aureus-infected mammary glands that were stimulated to rapidly grow and develop. Estradiol and progesterone injections were administered to 18 nonlactating dairy cows to induce mammary growth, and 2 quarters from each animal were infused with saline or Staph. aureus. Mammary tissues were collected at 5 (n = 9) and 10 d (n = 9) postinfusion and examined using quantitative bright field and florescent immunohistochemistry. Staphylococcus aureus mammary glands tended to have a greater number of mammary epithelial cells undergoing apoptosis than saline quarters. In the stromal compartment, challenged quarters contained a lower proportion of cells undergoing apoptosis than saline quarters overall; however, cell types undergoing apoptosis were differentially affected. Staphylococcus aureus quarters contained a lesser percentage of apoptotic fibroblasts while also containing more nonapoptotic immune cells than saline quarters in the intralobular stroma compartment. A similar number of proliferating epithelial cells were present in Staph. aureus and saline mammary tissues, but more proliferating cells were present in the intralobular stroma compartment of Staph. aureus-infused quarters than those infused with saline. When these cellular responses are considered together, it indicates that changes in cellular apoptosis and proliferation contribute to changes in the gland structure by potentiating the expansion of the intralobular stromal compartment, via cellular accumulation, and limiting the amount of epithelium due to increases in cellular apoptosis in affected glands. Reductions in mammary epithelium are expected to reduce future milk yields and productive herd life.

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.

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.

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.

It is established that the ovary and estrogen are essential to bovine mammary development with the onset of puberty. Recent studies have shown that ovariectomy in the very early prepubertal period, well before onset of puberty, also dramatically impairs mammary growth. Similarly, prepubertal heifers treated with the antiestrogen tamoxifen (TAM) also exhibit markedly impaired mammary growth in correspondence with reduced estrogen receptor α (ESR1) expression. Our objective was to evaluate the effect of TAM on the mammary stroma and specifically to determine if the reported decrease in mammary development was related to changes in TAM-induced alterations in the stroma surrounding the mammary parenchyma. Briefly, 16 Holstein heifers calves were randomly assigned to one of 2 treatment groups: TAM-injected or control. Calves were administered TAM (0.3 mg kg1 d1) or placebo from 28 to 120 d of age. At day 120, calves were euthanized and udders removed. Mammary tissue from near the boundary between the parenchyma and surrounding mammary fat pad was collected for histology and morphometric analysis, expression of selected extracellular matrix–related genes, and quantitation of stromal collagen deposition by study of Sirius Red-stained tissue sections imaged with polarized light. Compared with tissue from control heifers, TAM heifers frequently exhibited areas with abundant fibroblasts and mesenchymal cells especially within the intralobular stroma, as well as less complex ductal structures. Among the array of extracellular matrix–related genes tested, only a small difference (P

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.

Preweaning diet and estradiol treatment alters mammary development. Our objectives were to study the effects of diet and estradiol on proliferation of mammary epithelial cells and expression of estrogen receptor α (ESR1) and progesterone receptors (PGR) in these cells. Thirty-six Holstein heifer calves were raised on (1) a control milk replacer fed at 0.44 kg of powder/head per day, dry matter (DM) basis (restricted, R; 20.9% crude protein, 19.8% fat, DM basis), or (2) an enhanced milk replacer fed at 1.08 kg of powder/head per day, DM basis (Enhanced, EH; 28.9% crude protein, 26.2% fat, DM basis). Milk replacer was fed for 8 wk. At weaning, a subset (n = 6/diet) of calves were euthanized and had tissue harvested. Remaining calves received estradiol implants (E 2 ) or placebo and were euthanized at wk 10 to harvest tissue. Treatments were (1) R, (2) R + E 2 (R-E2), (3) EH, and (4) EH + E 2 (EH-E2). One day before euthanasia calves were given bromo-2′-deoxyuridine (BrdU; 5 mg/kg of body weight). At euthanization, mammary parenchyma was removed and fixed. Tissue sections from zone 1 (cisternal), 2 (medial), and 3 (distal) within the mammary gland were stained with hematoxylin and eosin and antibodies to measure expression of ESR1, PGR, and incorporation of BrdU. At wk 8, R-fed calves had more PGR-expressing cells in distal parenchyma; however, PGR expression intensity was greater in EH-fed calves. The proportion of cells expressing ESR1 was not affected by diet, but expression intensity (receptors per positive cell) was greater in EH-fed calves across all zones (62–81%). Overall, the percent BrdU-positive epithelial cells was 2 and 0.5 fold greater for EH-fed calves in zone 2 and 3. The proportion of labeled cells was greater in terminal ductal units than in subtending ducts, and treatment effects were more evident in terminal ductal units. At wk 10, calves treated with estradiol had 3.9-fold greater PGR expression intensity. The intensity and percent of cells expressing ESR1 was lowest in estradiol-treated calves. Overall, estradiol-treated calves had the greatest number of proliferating epithelial cells. Moreover, in zone 3, EH-E2 calves had a higher percentage of proliferating cells than in all other treatments. Results indicate both diet and estradiol administration alter proliferation rates of the mammary epithelium and that changes in expression of ESR1 and PGR are involved in enhanced mammary development. The data support our hypothesis that enhanced preweaning feeding increases the mammary tissue responsiveness to mammogenic stimulation.

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.

Prepubertal mammary development involves elongation and branching of ducts and stromal tissue remodeling. This process is closely linked with ovarian and pituitary hormones, growth factors, and local regulators. Accumulating evidence suggests that the myoepithelial cells also play a role in ductal development in addition to their well-recognized importance in the milk ejection reflex. Following reports that myoepithelial cells changed in correspondence with decreased mammary growth after ovariectomy of prepubertal heifers, we evaluated myoepithelial cells in mammary tissue collected from prepubertal heifers treated with the antiestrogen tamoxifen. Briefly, heifers were given placebo (n=7) or tamoxifen (n=8; 0.3mg/kg per day) beginning on d 28 of life until the animals were euthanized on d 120. Tissues were collected from each of 3 zones (near the gland cistern, midway between the gland cistern and mammary fat pad, and at the interface of the parenchyma and mammary fat pad). Samples were processed to measure expression of transformation-related protein 63 (p63), smooth muscle actin, and common acute lymphoblastic leukemia antigen. We found that smooth muscle actin and common acute lymphoblastic leukemia antigen were expressed in the cytoplasm and p63 in the nuclei of myoepithelial cells. In concert with a 50% impairment in mammary growth after tamoxifen, we found that the number of myoepithelial cells around developing mammary ducts was reduced. But the average intensity of p63 expression per nucleus was not affected. We used the very distinct and exclusive staining of p63 in myoepithelial cell nuclei to capture hundreds of nuclear images for subsequent analysis using CellProfiler software. From this image analysis, we found that the area of myoepithelial cell nuclei and perimeter distances were reduced by tamoxifen. When nuclei were classified based on nuclear shape (eccentricity), we found differences in area, perimeter, and patterns of p63 expression based on Zernike number evaluations as well as treatment differences within each shape classification. These data provide support to the concept that myoepithelial cells are also the involved in mammary development in the prepubertal bovine mammary gland and that use of multispectral imaging combined with image analysis software can provide quantitative data to better understand the complex cellular interactions that ultimately regulate mammary morphogenesis in the bovine.

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.

For a pet diet to be labeled as human-grade, every ingredient and the finished food must be stored, handled, processed, and transported according to the current good manufacturing practices for human edible foods. Human-grade dog foods are now available and increasing in popularity, but little research has been conducted to test the digestibility of these foods. For this reason, the objective of this experiment was to determine the true nutrient and amino acid (AA) digestibilities of dog foods formulated with human-grade ingredients 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 LLC (Irvine, CA). Before analysis, all foods were lyophilized and ground. A precision-fed rooster assay using cecectomized roosters was conducted to determine the true nutrient digestibility and standardized AA digestibilities of the foods tested. Conventional roosters were used to determine the nitrogen-corrected true metabolizable energy (TMEn) of the foods. 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 and AA composition. All data were analyzed using the Mixed Models procedure of SAS (version 9.4; SAS Institute, Cary, NC). In general, all foods tested were highly digestible. Dry matter digestibility was similar among CWR, LBR, and TWR foods, and greater (P < 0.0001) than that of FSP and VSR foods. Organic matter digestibility was highest (P = 0.0002) for CWR and lowest (P = 0.0002) for VSR. For the majority of indispensable AA, digestibilities were greater than 85%, with some being greater than 90%. TMEn was higher (P < 0.0001) for BRP than the other foods, which were similar to one another. Also, TMEn values were much higher than what would be estimated by using modified Atwater factors and often above the predictive equations for metabolizable energy (ME) recommended by the National Research Council or by using Atwater factors. Although statistical differences were observed among foods, they all performed well and the foods tested had very high AA digestibilities. Additionally, the TMEn data suggest that existing methods and equations for ME prediction underestimate the energy content of the foods tested.

Preweaning diet is known to affect rumen tissue appearance at the gross level. The objectives of this experiment were to investigate effects of different preweaning diets on the growth and development of the rumen epithelium and on putative rumen epithelial stem and progenitor cell measurements at the gene and cell levels. Neonatal Holstein bull calves (n = 11) 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). Water was available ad libitum and feed and water intake were recorded daily. Putative stem and progenitor cells were labeled by administering a thymidine analog (5-bromo-2'-deoxyuridine, BrdU; 5 mg/kg of body weight in sterile saline) for 5 consecutive days and allowed a 25-d washout period. Calves were killed at 43 ± 1 d after a 6 h exposure to a defined concentration of volatile fatty acids. We obtained rumen tissue from the ventral sac and used it for immunohistochemical analyses of BrdU (putative stem and progenitor cells) and Ki67 (cell proliferation), gene expression analysis, and morphological measurements via hematoxylin and eosin staining. Epithelial stem and progenitor cell gene markers of interest, analyzed by real-time quantitative PCR, were β1-integrin, keratin-14, notch-1, tumor protein p63, and leucine-rich repeat-containing G protein-coupled receptor 5. Body growth did not differ by diet, but empty reticulorumens were heavier in MRS calves (MRS: 0.67 ± 0.04 kg; MRO: 0.39 ± 0.04 kg). The percentage of label-retaining BrdU basale cells was higher in MRO calves than in MRS calves (2.0 ± 0.3% vs. 0.3 ± 0.2%, respectively). We observed a higher percentage of basale cells undergoing proliferation in MRS calves than in MRO calves (18.4 ± 2.6% vs. 10.8 ± 2.8%, respectively). Rumen epithelial gene expression was not affected by diet, but the submucosa was thicker in MRO calves and the epithelium and corneum/keratin layers were thicker in MRS calves. Presumptive stem and progenitor cells in the rumen epithelium were identifiable by their ability to retain labeled DNA in the long term, changed proliferative status in response to diet, and likely contributed to observed treatment differences in rumen tissue thickness.

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.

Feeding heifers a higher plane of nutrition postweaning but before puberty can negatively affect mammary gland development and future milk yield. However, enhanced nutrition preweaning may promote development and future production. Our objectives were to determine the effects of enhanced feeding preweaning and exogenous estrogen immediately postweaning on mammary gland development and the composition of the mammary parenchyma (PAR) and mammary fat pad (MFP). Thirty-six Holstein heifer calves (

BACKGROUND Stable isotope amino acids are regularly used as tracers to examine whole-body and muscle protein metabolism in humans. To accurately assess in vivo dietary protein digestion and absorption kinetics, the amino acid tracer is required to be incorporated within the dietary protein food source (i.e., intrinsically labeled protein). OBJECTIVE We assessed the practicality of producing eggs and poultry meat intrinsically labeled with l-[5,5,5-(2)H3]leucine through noninvasive oral tracer administration. METHODS A specifically formulated diet containing 0.52% leucine was supplemented with 0.3% l-[5,5,5-(2)H3]leucine and subsequently fed to 3 laying hens (Lohmann LSL Whites) for 55 d. On day 55, the hens were slaughtered and their meat, bones, and organs were harvested to determine tissue labeling. In Expt. 1, 2 healthy young men [mean ± SEM age: 22 ± 1.5 y; mean ± SEM body mass index (BMI; in kg/m(2)): 23.7 ± 0.5] ingested 18 g l-[5,5,5-(2)H3]leucine-labeled egg protein. In Expt. 2, 2 healthy young men (mean ± SEM age: 20.0 ± 0.0 y; mean ± SEM BMI: 26.4 ± 3.1) ingested 28 g l-[5,5,5-(2)H3]leucine-labeled poultry meat protein. Plasma samples (Expts. 1 and 2) and muscle biopsies (Expt. 1) were collected before and after labeled-food ingestion. RESULTS High tracer labeling [>20 mole percent excess (MPE)] in the eggs was obtained after 7 d and maintained throughout the feeding protocol (P < 0.05). Over a 55-d period, ∼850 g egg protein (145 eggs) was produced, with a mean ± SEM tracer enrichment of 22.0 ± 0.8 MPE. Mean ± SEM l-[5,5,5-(2)H3]leucine enrichment in the meat was 9.6 ± 0.1 MPE. In Expts. 1 and 2, the consumption of labeled eggs and poultry meat protein increased plasma l-[5,5,5-(2)H3]leucine enrichment, with mean ± SEM peak values of 6.7 ± 0.1 MPE and 4.0 ± 0.9 MPE, respectively. The mean ± SEM 5-h postprandial increase in myofibrillar l-[5,5,5-(2)H3]leucine enrichment after egg ingestion in healthy young men was 0.051 ± 0.008 MPE (Expt. 1). CONCLUSION We demonstrated the feasibility of producing intrinsically labeled eggs and poultry meat for use in human metabolic research.

Research has shown that changes in nutrition both before and after weaning can affect mammary development. Additionally, estrogen is known to be a potent mammogenic stimulant. Our objectives were to determine effects of altered preweaning feeding and exogenous estradiol postweaning on growth, intake, and health. Thirty-six Holstein heifer calves were reared on (1) a restricted milk replacer (MR) diet fed at 0.44kg powder dry matter (DM)/day [R; 20.9% crude protein (CP), 19.8% fat, DM basis], or (2) an enhanced MR fed at 1.08kg powder DM/d (EH; 28.9% CP, 26.2% fat, DM basis). The MR feeding was reduced 50% during wk 8 to prepare for weaning. Starter was offered after wk 4 but balanced between treatments. Body weight and frame were measured weekly with intakes and health monitored daily. At weaning, a subset of calves were slaughtered (n=6/diet). Enhanced-fed calves had greater carcass, thymus, liver, spleen, and mammary gland (parenchyma and mammary fat pad) weights. The EH calves also had greater average daily gain (ADG) starting during wk 1 (0.36 vs. −0.06kg/d) and lasting through wk 7 (1.00 vs. 0.41kg/d). Remaining calves received estrogen implants or placebo and were slaughtered at the end of wk 10, creating 4 treatments: (1) R, (2) R + estrogen (R-E2), (3) EH, and (4) EH + estrogen (EH-E2). Postweaning ADG was similar between R, EH, and EH-E2 calves, but greater in R-E2 calves than E calves. The EH-E2 calves had the heaviest mammary glands, and R-E2 calves had heavier mammary glands than R calves. The EH calves consumed more MR DM, CP, and fat preweaning. The R-fed calves consumed more starter DM preweaning. Fecal score was greater for EH calves (1.74 vs. 1.50) preweaning, but days medicated did not differ. Fecal scores were lower for R-E2 calves postweaning. Improved preweaning feeding of calves increased body weights and frame measures. Differences in body weights remained postweaning. Enhanced-fed calves showed greater ADG during the preweaning period but not postweaning. Exogenous estrogen may elicit diet-dependent growth responses. Analysis of collected samples will allow determination of cellular and molecular processes responsible for the marked differences in mammary development observed.

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.

Intramammary infections (IMI) are prevalent in nonlactating dairy cattle and are known to alter mammary structure and negatively affect the amount of mammary epithelium in the gland. Mechanisms responsible for the observed changes in mammary growth during an IMI are poorly understood, yet the importance of the key mammogenic hormones driving mammary growth is well recognized. This study's objective was to characterize the expression of estrogen receptor α (ESR1) and progesterone receptor (PGR) in mammary glands stimulated to grow and develop in the presence or absence of an IMI as well as preliminarily characterize myoepithelial cell response to IMI. Mammary growth was stimulated in 18 nonpregnant, nonlactating dairy cows using subcutaneous estradiol and progesterone injections, and 2 culture-negative quarters of each cow were subsequently infused with either saline (n = 18) or Staphylococcus aureus (n = 18). Mammary parenchyma tissues were collected 5 d (n = 9) or 10 d (n = 9) postchallenge and examined using immunofluorescence microscopy to quantify positive nuclei and characterize staining features. There tended to be a greater number of ESR1-positive nuclei observed across 8 random mammary parenchyma fields of view in saline quarters than in Staph. aureus quarters (201 vs. 163 ± 44 nuclei). Saline quarters also contained a greater number of PGR-positive nuclei (520 vs. 440 ± 45 nuclei) and myoepithelial cells (971 vs. 863 ± 48 nuclei) than Staph. aureus-challenged quarters. However, when ESR1, PGR, and myoepithelial nuclei counts were adjusted for Staph. aureus quarters containing less epithelium, differences between quarter treatments abated. The examined ESR1 and PGR staining characteristics were similar between saline and Staph. aureus quarters but were differentially affected by day of tissue collection. Additionally, nuclear staining area of myoepithelial cells was greater in Staph. aureus quarters than in saline quarters. These results indicate that IMI had little effect on the number or staining characteristics of ESR1- or PGR-positive nuclei relative to epithelial area, but myoepithelial cells appear to be affected by IMI and the associated inflammation in nonlactating mammary glands that were stimulated to grow rapidly using mammogenic hormones. Accordingly, reductions in mammary epithelium in affected glands are not suspected to be resultant of alterations in the number or staining characteristics of ESR1- or PGR-positive mammary epithelial cells.

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.