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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

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.

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.

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.

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.

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.

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.

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.

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

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

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

This study evaluated the nutritional value of 14 canola meals from new varieties of canola and compared them to conventional canola meal samples and soybean meals in chickens. Five experiments that included different sources of canola meals or soybean meals were conducted. For each experiment, a precision-fed rooster assay with conventional or cecectomized roosters was conducted to determine TMEn or amino acid digestibility. Analyzed nutritional composition of the canola meal samples indicated increases in crude protein and amino acids for all test canola meals (49.41 to 50.58% crude protein on a dry matter basis) compared to conventional canola meals (40.73 to 43.01%). All test canola meals also contained lower amounts of neutral detergent fiber and acid detergent fiber. Most test canola meals had significantly higher TMEn values than the conventional canola meals (P < 0.05), but all were lower than the soybean meal (P < 0.05). The test canola meals had higher amino acid digestibility coefficients than conventional canola meals in Experiments 1, 2, and 4 (P < 0.05), and higher concentrations of digestible amino acids in all 5 experiments. The results of this study indicated that nutritional value of the canola meal from new varieties of canola was greater than conventional canola meal for poultry.

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

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

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

The objective of this study was to determine standardized AA digestibility of corn, corn gluten meal, and 3 distillers dried grains with solubles (DDGS) using the precision-fed cecectomized rooster assay (PFR), the standardized ileal AA broiler chicken assay (SIAAD), and a newly developed precision-fed ileal broiler chicken assay (PFC). For the PFR, cecectomized roosters were precision-fed approximately 30 g of feed sample, and excreta were collected 48 h postfeeding. For the SIAAD, 16-d-old broilers were ad libitum fed a semi-purified diet containing the feed samples as the sole source of protein from 17 to 21 d, with ileal digesta collected at 21 d. For the PFC, 22-d-old broiler chickens were precision-fed 10 g of feed and ileal digesta were collected at 4 h postfeeding. For corn, the PFC yielded significantly higher digestibilities than the SIAAD and PFR for several AA. For corn gluten meal, the PFR yielded significantly higher values than the PFC for the majority of the AA, with the SIAAD yielding intermediate values. When 3 DDGS samples were evaluated, the PFR produced higher digestibilities than the PFC for all 3 DDGS samples for most of the AA. When comparing the PFR and the SIAAD, the PFR yielded higher values than the SIAAD for one DDGS, whereas there was generally no significant difference between these 2 methods for the other 2 DDGS samples. The results of this study indicate there were differences among standardized AA digestibility values for the PFR, SIAAD, and PFC in some instances. The differences among methods were not consistent; however, the PFR yielded higher digestibility values than the PFC for 4 of the 5 ingredient samples.

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

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

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

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

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

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

An experiment was conducted using 504 Hy-Line W-36 Single Comb White Leghorn hens (69 wk of age) randomly assigned to 1 of 7 treatments. These treatments consisted of a 47% corn:47% soy hulls diet (C:SH) fed ad libitum; a 94% corn diet fed at a rate of 36.3, 45.4, or 54.5 g/hen per day (CORN 36, CORN 45, and CORN 54, respectively); and a 94% corn distillers dried grains with solubles (DDGS) diet fed at the same rates as the previous corn diets (DDGS 36, DDGS 45, and DDGS 54, respectively) during the molt period of 28 d. The intent was to feed the DDGS diets for 28 d; however, all hens on these diets had very low feed intakes and greater than anticipated BW loss. Thus, they were switched to a 16% CP corn-soybean meal layer diet on d 19 of the molt period. At d 28, hens on all treatments were fed the same corn-soybean meal layer diet for 39 wk (73 to 112 wk of age). All DDGS diets and the CORN 36 diet resulted in total cessation of egg production during the molt period and egg production of hens fed the CORN 45, CORN 54, and C:SH diets had decreased to 3 and 4%, respectively, by d 28. Body weight loss during the 28-d molt period ranged from 14% for the CORN 54 diet to approximately 23% for the 3 DDGS diets. Postmolt egg production (5 to 43 wk) was higher for hens fed the DDGS molt diets than those fed the corn diets. There were no consistent differences in egg mass, egg-specific gravity, feed efficiency, or layer feed consumption among molt treatments for the postmolt period. These results indicate that limit feeding corn diet and DDGS diet in non-feed-withdrawal molt programs will yield long-term postmolt performance that is comparable to that observed by ad libitum feeding a C:SH diet.

Five experiments were conducted to evaluate the effects of whole wheat, whole sorghum, or whole barley on nutrient digestibility, growth performance, and cecal short-chain fatty acid concentrations when supplemented primarily at the expense of corn in ground corn-soybean meal control diets. The first 4 experiments utilized New Hampshire x Columbian male chicks. In the first 2 experiments, feeding 5, 10, 15, or 20% whole wheat had no effect on growth performance at 21 d when compared with chicks fed the control diet. The third experiment tested 20, 35, and 50% whole wheat fed from 0 to 21 d of age and showed that a 50% whole wheat diet decreased (P

Four chick bioassays were conducted to evaluate the threonine (Thr) replacement value of L -homoserine (HS). Growth rate was increased (P < 0.05) by dietary addition of 800 mg L -HS/kg diet to a purified diet severely deficient in Thr or by the addition of 800 or 1000 mg of L -HS/kg diet to a corn-peanut meal diet distinctly deficient in Thr. The addition of an isomolar level of α-ketobutyrate, a catabolic product of both Thr and HS, did not elicit a response. Standard-curve methodology predicted a Thr replacement value of 38 ± 9% for HS. Interactions (P < 0.01) were observed in assays 2 and 4 between dietary Thr adequacy and 800 or 1000 mg L -HS/kg supplementation. Thus, HS improved growth performance when added to a Thr-deficient diet (0.46 g Thr/100 g diet), but it decreased growth performance when added to the same diet containing surfeit Thr (0.80 g Thr/100 g diet). The results indicate that low levels of HS elicit a growth response in young chicks fed Thr-deficient diets.

Two experiments were conducted with New Hampshire x Columbian chicks fed a corn-soybean meal diet and 1 experiment was conducted with chicks fed a dextrose-isolated soy protein diet to examine the effects of inulin, oligofructose, mannanoligosaccharide (MOS), short-chain fructooligosaccharide (SCFOS), and transgalactooligosaccharide on growth performance, ME(n), digestibility of amino acids (AA), and cecal microbial populations. Each diet was fed to chicks from 0 to 21 d of age, and excreta were collected at 3-4, 7, 14, and 21 d of age in both experiments. Neither 4 nor 8 g of oligosaccharides/kg had a significant effect on growth performance. The ME(n) and AA digestibility values increased with increasing age. Feeding 8 g/kg of inulin and SCFOS had a negative effect (P

This study was conducted to evaluate the effects of Grobiotic-P (GB), a prebiotic-type product that contains dairy and yeast fractions and dried fermentation extracts, on growth performance and nutrient digestibility at 4 and 21 d of age and cecal populations of Bifidobacterium, Lactobacillus, Escherichia coli, and Clostridium perfringens at 21 d of age. Two experiments were conducted using male New Hampshire x Columbian chicks. The first experiment evaluated GB at 2, 4, and 6% in a corn-soybean meal diet and compared these dietary treatments to a diet containing no GB (negative control) and a diet containing an antibiotic growth promoter (positive control), bacitracin methylene disalicylate. The second experiment used semi-purified dextrose-casein and dextrose-isolated soy protein diets to examine the effects of a 5% GB addition. In the first experiment, supplementing GB at 2, 4, and 6% in a corn-soybean meal diet had no effect on weight gain (P0.05). Feed efficiency and ME(n) were decreased (P0.05) by feeding 4 and 6% GB for some time periods, suggesting that the ME(n) value of GB used in diet formulation was too high. The GB had no consistent effect on apparent digestibility of amino acids. Cecal lactobacilli populations were linearly increased (P0.05) by GB in a corn-soybean meal diet in experiment 1. In the second experiment, the cecal populations of bifidobacteria were increased (P0.05) when 5% GB was supplemented to chicks fed a dextrose-casein diet, and the cecal populations of E. coli and C. perfringens were reduced (P0.05) when 5% GB was supplemented to chicks fed a dextrose-isolated soy protein diet. The results of this study indicate that feeding GB to chicks may promote the growth of beneficial bifidobacteria while reducing the growth of E. coli and C. perfringens in the ceca.

An experiment using 216 Hy-Line W-36 pullets was conducted to evaluate transgenic maize grain containing the cry34Ab1 and cry35Ab1 genes from a Bacillus thuringiensis (Bt) strain and the phosphinothricin ace-tyltransferase (pat) gene from Streptomyces viridochromogenes. Expression of the cry34Ab1 and cry35Ab1 genes confers resistance to corn rootworms, and the pat gene confers tolerance to herbicides containing glufosinate-ammonium. Pullets (20 wk of age) were placed in cage lots (3 hens/cage, 2 cages/lot) and were randomly assigned to 1 of 3 corn-soybean meal dietary treatments (12 lots/treatment) formulated with the following maize grains: near-isogenic control (control), conventional maize, and transgenic test corn line 59122 containing event DAS-59122-7. Differences between 59122 and control group means were evaluated with statistical significance at P < 0.05. Body weight and gain, egg production, egg mass, and feed efficiency for hens fed the 59122 corn were not significantly different from the respective values for hens fed diets formulated with control maize grain. Egg component weights, Haugh unit measures, and egg weight class distribution were similar regardless of the corn source. This research indicates that performance of hens fed diets containing 59122 maize grain, as measured by egg production and egg quality, was similar to that of hens fed diets formulated with near-isogenic corn grain.

The aim of this study was to determine the effect of the standardization method and age on standardized ileal amino acid digestibility (SIAAD) of 4 meat and bone meal (MBM) samples in broiler chicks and turkey poults. The SIAAD were obtained by correcting apparent ileal digestibility (AID) values for basal ileal endogenous amino acid flow obtained from chicks and poults fed a N-free diet or a highly digestible protein diet (HDP; 100 g of casein/kg of diet). Four diets were formulated to contain 20% CP by using MBM as the only source of CP. Each diet was fed to 6 replicate cages of 30 or 8 birds/cage at 5 and 21 d, respectively, for 5 d. With the exception of all-beef MBM, chick AID values on d 21 were higher (P < 0.05) than on d 5. In poults, however, AID was not different between the 2 ages, with the exception of His, which was higher (P < 0.05) at d 21. There was no difference between methods on SIAAD on d 5 or 21 for all 4 MBM samples in either species. There was no effect of the method of standardization on SIAAD at either age for most amino acids. For chicks, however, standardization of the all-beef MBM sample with HDP resulted in higher (P < 0.05) SIAAD values for most of the amino acids (d 5). In poults at d 5, however, the SIAAD for most of the amino acids in the blended MBM were higher (P < 0.05) with HDP correction. The CV in SIAAD in chicks between the 2 methods of standardization was higher on d 5 (8.1%) relative to d 21 (5.0%) for all treatments. In poults, greater variability was observed on d 21 (8.2%) relative to d 5 (6.7%). Results from this study showed that at d 21, SI-AAD with either the N-free or the HDP diet resulted in similar digestibility values.

Prebiotics, such as indigestible oligosaccharides, are considered to be possible dietary alternatives to antibiotic growth promoters in poultry. The effects of indigestible oligosaccharides on nutrient digestibility in poultry are largely unknown. Therefore, an experiment was conducted to evaluate the effects of several oligosaccharides on amino acid digestibility and TMEn in roosters. The dietary treatments consisted of a corn-isolated soy protein control diet or that diet supplemented with 4 or 8 g/kg of inulin, oligofructose, mannanoligosaccharide (MOS), short-chain fructooligosaccharide, or transgalactooligosaccharide (TOS). Each of the 11 diets was tube-fed (30 g) to 4 cecectomized and 4 intact Single Comb White Leghorn roosters that had been fasted for 24 h. Excreta were then collected for the following 48 h, freeze-dried, and analyzed for amino acid content. The true digestibility of lysine and valine was increased (P0.05) in cecectomized roosters fed 8 g/kg of MOS or TOS when compared with roosters fed the control diet. In addition, methionine digestibility was improved (P0.05) in cecectomized roosters fed 4 g/kg of MOS or short-chain fructooligosaccharide and by 8 g/kg of oligofructose or TOS. The true digestibility of isoleucine was increased (P0.05) in cecectomized roosters fed 8 g/kg of MOS or 4 or 8 g/kg of TOS. The magnitude of the increases in amino acid digestibility coefficients for cecectomized roosters ranged from 3 to 9 percentage units. Feeding either 4 or 8 g/kg of inulin to intact roosters decreased (P0.05) the true digestibility of methionine. The oligosaccharides generally had no significant effect on TMEn. The results of this study indicated that the indigestible oligosaccharides had no significant effect on the digestibility of most amino acids in a corn-isolated soy protein diet. The digestibility of a few amino acids, however, was increased by some oligosaccharides in cecectomized roosters but not in intact roosters.

The immobilized digestive enzyme assay (IDEA) was run on 6 soybean meal (SBM) samples and compared with true amino acid digestibility (TAAD) content, as determined using cecectomized roosters. The IDEA values were excellent TAAD predictors as evidenced by R(2) values of 0.90 and 0.88 for lysine and cystine, respectively. The original IDEA took 2.5 d to run, and therefore we modified the protocol to reduce the time to 18 h. This modified IDEA procedure was run on 17 SBM samples, and IDEA values were shown to be excellent predictors of TAAD content. This IDEA SBM kit was validated by predicting the TAAD of 5 SBM not included in the 17-sample set above and the comparison of the predicted vs. determined TAAD. Finally, the IDEA SBM kit was used to compare the predicted TAAD of 338 SBM samples from around the world. The predicted lysine digestibility on the world survey samples ranged from 70.6 to 95.5% with an average of approximately 89%, and the ranges and means of the other amino acid digestibilities were also calculated.

Previous studies have reported that increased heat processing and feeding larger particle size ingredients may increase the bioavailability of phytate P in some feedstuffs. Therefore, one chick experiment was conducted to determine the effect of various increased heat processing treatments on bioavailability of P in corn distillers dried grains with solubles (DDGS), and 2 chick experiments were conducted to determine the effect of particle size on bioavailability of P in DDGS. In addition, one precision-fed cecectomized rooster assay was conducted to evaluate the effects of increased heating on amino acid digestibility. For the chick experiments, a P-deficient cornstarch-dextrose-soybean meal basal diet containing 0.10% nonphytate P was supplemented with 0.0, 0.05, or 0.10% P from KH(2)PO(4) or 1 of 2 levels of DDGS. Diets were fed from 8 to 22 d of age, and P bioavailability relative to the P in KH(2)PO(4) was estimated using the standard curve or slope-ratio methods with tibia ash as the response variable. Increased heating of DDGS by autoclaving at 124 kPa and 121 degrees C for 60 to 80 min or by heating in a drying oven at 121 degrees C for 60 min significantly increased relative P bioavailability in DDGS (from 70 to as high as 91%) in several treatments. Amino acid digestibility, however, was greatly reduced by increased heating in most cases, particularly for Lys. Relative bioavailability of P was not significantly affected by DDGS particle sizes ranging from 542 to 837 microm. Our results indicated that increased heating of DDGS increased bioavailability of P but decreased digestibility of amino acids, particularly Lys, and that bioavailability of P was not affected by particle size.

The DE values of corn grain for pigs will differ among corn sources. More accurate predic- tion of DE may improve diet formulation and reduce diet cost. Corn grain sources (n = 83) were assayed with growing swine (20 kg) in DE experiments with total collection of feces, with 3-wk-old broiler chick in nitro- gen-corrected apparent ME (AME N ) trials and with cecectomized adult roosters in nitrogen-corrected true ME (TME N ) studies. Additional AME N data for the corn grain source set was generated based on an existing near-infrared transmittance prediction model (near- infrared transmittance-predicted AME N (NIT-AME N )). Corn source nutrient composition was determined by wet chemistry methods. These data were then used to 1) test the accuracy of predicting swine DE of individual corn sources based on available literature equations and nutrient composition and 2) develop models for pre- dicting DE of sources from nutrient composition and the cross-species information gathered above (AME N , NIT-AME N , and TME N ). The overall measured DE, AME N , NIT-AME N , and TME N values were 4,105 ± 11, 4,006 ± 10, 4,004 ± 10, and 4,086 ± 12 kcal/kg DM, respectively. Prediction models were developed using 80% of the corn grain sources; the remaining 20% was reserved for validation of the developed prediction equation. Literature equations based on nutrient com- position proved imprecise for predicting corn DE; the root mean square error of prediction ranged from 105 to 331 kcal/kg, an equivalent of 2.6 to 8.8% error. Yet among the corn composition traits, 4-variable models developed in the current study provided adequate pre- diction of DE (model R 2 ranging from 0.76 to 0.79 and root mean square error (RMSE) of 50 kcal/kg). When prediction equations were tested using the validation set, these models had a 1 to 1.2% error of prediction. Simple linear equations from AME N , NIT-AME N , or TME N provided an accurate prediction of DE for indi- vidual sources (R 2 ranged from 0.65 to 0.73 and RMSE ranged from 50 to 61 kcal/kg). Percentage error of prediction based on the validation data set was greater (1.4%) for the TME N model than for the NIT-AME N or AME N models (1 and 1.2%, respectively), indicat- ing that swine DE values could be accurately predicted by using AME N or NIT-AME N. In conclusion, regres- sion equations developed from broiler measurements or from analyzed nutrient composition proved adequate to reliably predict the DE of commercially available corn hybrids for growing pigs.

This experiment was designed to evaluate the effects of selected soybean (SB) processing byproducts (gums, oil, soapstock, weeds/trash) when added back to soybean meal (SBM) during processing on the resulting nutrient composition, protein quality, nutrient digestibility by swine, and true metabolizable energy (TMEn) content and standardized AA digestibility by poultry. To measure ileal DM and nutrient digestibility, pigs were surgically fitted with a T-cannula in the distal ileum. The concentration of TMEn and the standardized AA digestibility by poultry were determined using the precision fed cecectomized rooster assay. Treatments in the swine experiment included SBM with no by-products; SBM with 1% gum; SBM with 3% gum; SBM with 0.5% soapstock; SBM with 1.5% soapstock; SBM with 2% weeds/trash; SBM with a combination of 3% gum, 1.5% soapstock, and 2% weeds/trash; SBM with 5.4% soybean oil; and roasted SB. A 10 x 10 Latin square design was utilized. The experiment was conducted at the University of Illinois, Urbana-Champaign, and at The Ohio State University, Columbus. In the swine experiment, apparent ileal DM, OM, CP, and AA digestibilities were reduced (P < 0.05) when pigs consumed the combination by-product diet compared with the diet containing no by-products. Apparent ileal digestibilities of DM, CP, and total essential, total nonessential, and total AA were lower (P < 0.05) for any diet containing by-products compared with the diet with no by-products. Apparent ileal digestibilities of DM, OM, CP, and AA were lower (P < 0.05) for the roasted SB-compared with the SB oil-containing diet. In the rooster experiment, TMEn values were greater (P < 0.05) for roasted SB compared with SBM with no by-products and increased linearly as the addition of soapstock increased. Individual, total essential, total nonessential, and total AA digestibilities were lower (P < 0.05) for roosters fed roasted SB versus SBM devoid of by-products. Gums, soapstock, and weeds/trash reduce the nutritive value of the resultant meal when they are added back during processing.

Three experiments were conducted to evaluate the effectiveness of OptiPhos phytase and citric acid for releasing the P that is not bioavailable in distillers dried grains with solubles (DDGS). The effect of OptiPhos phytate on AME(n) and amino acid digestibility was also determined. New Hampshire x Columbian chicks were fed experimental diets from 8 to 21 d of age. For Experiment 1, a basal P-deficient diet contained 40% DDGS plus supplemental amino acids, and DDGS was the only source of P. The basal diet was then supplemented with 1,000 or 10,000 phytase units (FTU)/kg of OptiPhos phytase or with 0.2% of P from KH2PO4. In Experiment 2, a slope-ratio chick growth and tibia ash assay used a P-deficient soybean meal basal diet, and it was found that the bioavailability of P in DDGS was 67%. For Experiment 3, a P-deficient basal diet with 30% DDGS plus supplemental amino acids was supplemented with 0.05 or 0.1% P from KH2PO4, with 3% citric acid, or with 1,000 or 10,000 FTU/kg of OptiPhos phytase. In Experiment 1, both 1,000 and 10,000 FTU/kg of phytase increased tibia ash but had no effect on AME(n). Both 10,000 phytase units (FTU)/kg of phytase and supplemental P increased digestibility of amino acids. In Experiment 3, supplemental phytase and citric acid increased tibia ash (mg/tibia), and it was estimated that phytase and citric acid could release from 0.04 to 0.07% P from DDGS. In terms of bioavailability coefficients, the bioavailability of the P in DDGS was increased from 62 to 72%. These results indicate that phytase and citric acid increase the bioavailability of P in DDGS, but phytase at 1,000 FTU/kg had no consistent effect on AME(n) and amino acid digestibility.

In each of three 2-wk experiments, chicks were inoculated on d 9 or 11 with 5.0 x 10(5) Eimeria acervulina sporulated oocysts (acute infection) or on d 9, 12, 15, and 18 with 1.5 x 10(5) sporulated oocysts (chronic infection). In Experiment 1, both fish meal (15%) and GroBiotic-P (GB; International Ingredient Corporation, St. Louis, MO; 5%) diets completely ameliorated the negative effects of acute and chronic coccidiosis infection on growth performance of crossbred chicks. The acute coccidiosis infection greatly reduced MEn and amino acid (AA) digestibility, and the magnitude of response varied with the timing of excreta collection after inoculation. Both fish meal and GB diets ameliorated the large negative effects of coccidiosis infection on MEn and AA digestibility. In Experiment 2, a wheat-barley-pectin diet and acute coccidiosis infection depressed crossbred chick BW gain, AA digestibility, and MEn in comparison with a corn-soybean meal diet; there generally were no interactions between diet type and coccidiosis infection. In Experiment 3, using commercial broiler chicks, diets containing 2 to 6% GB did not improve the growth performance of coccidiosis-infected chicks, but they did improve the growth of the noninfected chicks. The results of this study indicate that coccidiosis infection (E. acervulina) reduces MEn and AA digestibility in chicks and that the coccidiosis effect is influenced by diet composition, type of infection (acute vs. chronic), and timing of excreta collection.

The objectives of this study were to determine if lengthening the time that soybeans (SB) spend in the extractor during preparation of soybean meal (SBM) results in increased relative bioavailability of phosphorus without negatively impacting true amino acid digestibilities, and to compare those modified SBM with that produced from a low-phytate SB. Three SBM were prepared under uniform conditions with the exception of the length of time SB spent in the extractor [45 min (300 rpm), 60 min (225 rpm), or 90 min (150 rpm)]. A SBM prepared from low-phytate SB was obtained for comparison. Relative phosphorus bioavailability in chicks and true amino acid digestibilities by cecectomized roosters were determined. Increasing the length of time that SB spent in the extractor from 45 to 90 min resulted in lower phytate phosphorus and increased phosphorus bioavailability from 34 to 56%. However, this increase came at the expense of available lysine status, with the SBM extracted for 90 min containing less total lysine and less digestible lysine than the SBM extracted for 45 min (traditional extraction time). Phosphorus bioavailability from SBM prepared from low-phytate SB was 1.5 times higher than for SBM extracted for 45 min. Increasing the length of time that SB spend in the extractor led to an increase in bioavailable phosphorus but a decrease in bioavailable lysine, potentially negating the positive effect on phosphorus.

Two experiments were conducted to determine if 2 laying hen strains, Hy-Line W-36 and Hy-Line W-98, would respond similarly to being fed corn-soybean meal diets (17% CP and 3.8% Ca) deficient in nonphytate P (NPP). In experiment 1, 3 diets with varying NPP levels (0.10, 0.14, and 0.45%) were fed to 6 replicate groups of 12 hens of each Hy-Line strain from 20 to 50 wk of age. Body weight, egg weight, egg mass, feed intake, and NPP intake were higher for W-98 hens compared with W-36 hens throughout the 30-wk period. The 0.10% NPP dietary treatment was terminated for both strains at 35 wk of age due to similar low egg production. Within each strain, there was no significant difference in egg production performance for hens fed 0.14% NPP compared with hens fed 0.45% NPP. In experiment 2,3 diets with varying levels of NPP (0.10, 0.13, and 0.45%) were fed to 5 replicate groups of 12 hens of each Hy-Line strain from 95 to 112 wk of age. The 0.10% NPP treatment rapidly and severely depressed egg production and was terminated at 99 wk of age for both strains. In addition, egg production and egg mass were depressed similarly in both strains fed 0.13% NPP. In conclusion, this research indicates that Hy-Line W-36 and Hy-Line W-98 hens responded similarly to dietary NPP deficiency, suggesting that both strains have similar NPP requirements.

Previous research from our laboratory has shown that phytase, citric acid, and 1alpha-hydroxycholecalciferol [1alpha-(OH) D3] individually improve phytate P use in young chicks fed a P-deficient corn-soybean meal (C-SBM) diet. The current study was conducted to evaluate combinations of these additives on phytate P utilization. In 3 chick experiments, male crossbred chicks (New Hampshire x Columbian) were fed experimental diets from 8 to 21 d of age. The C-SBM basal diet used in all assays contained no supplemental P and was calculated to provide 23% CP, 0.13% nonphytate P (0.39% total P), 0.62% Ca, 25 mg of cholecalciferol/kg, and 3,260 kcal of TME/kg. In all 3 experiments, factorial arrangements (2 x 2 or 2 x 2 x 2) were used to evaluate 2 levels of phytase (0 and 300 units/kg), citric acid (0 and 3 or 4%), and 1alpha(OH) D3 (0 and 5, 10, or 15 microg/kg). Phytase, citric acid, and 1alpha-(OH) D3 each increased weight gain and tibia ash in all 3 experiments. There were some significant interactions among the compounds, but these were not consistent across experiments. Using standard curve methodology for tibia ash data, it was estimated that 0.03, 0.02, and 0.04% P were released by 3% citric acid, 300 units of phytase/kg, and 5 microg 1alpha-(OH) D3/kg, respectively, and that the combination of all 3 compounds resulted in the release of 0.13% P. Our results indicate that all 3 compounds increased phytate P use, and that their effects were generally additive, with some possible synergism between citric acid and 1alpha-(OH) D3.

In experiment 1 (one cycle), hens were fed diets containing 0.10, 0.115, 0.125, 0.135, 0.15, or 0.45% available P (AP) from 40 to 56 wk of age, with the last diet being a positive control. Egg production, egg mass, and BW were reduced (P < 0.05) by all lower AP levels except 0.15% AP when compared with the 0.45% AP treatment. In the second experiment (two cycles with a molt), hens were initially fed diets containing 0.10, 0.12, 0.14, 0.16, 0.18, 0.20, or 0.45% AP from 21 to 63 wk of age. Diets containing 0.10, 0.12, and 0.14% AP were terminated at 35, 39, and 50 wk, respectively, due to low egg production and increased mortality. Hens fed 0.16% AP also had significantly lower production performance than hens fed 0.45% AP during the first cycle. Hens on the 0.16 to 0.45% AP treatments were induced molted at 64 wk of age by 10 d of feed removal. The hens were then returned to the same AP layer diet they had been fed from 21 to 63 wk. For the 68 to 108 wk postmolt second-cycle period, hens fed the 0.16 to 0.20% AP diets (166 to 209 mg/d) had significantly lower egg production, egg mass, and feed efficiency than hens fed 0.45% AP. The results of our study indicated that first-cycle hens required approximately 0.18% AP or 198 mg AP/hen per day, and molted hens in their second cycle had a requirement that was greater than 0.20% AP or 209 mg AP/hen per day.

The objective of this study was to evaluate several nonfeed removal methods compared with feed removal for induced molting of laying hens. An experiment was conducted using 576 Dekalb White hens (69 wk of age) randomly assigned to 1 of 8 dietary treatments. Two of these treatments consisted of feed removal for 10 d followed by ad libitum access to a 16% CP, corn-soybean meal diet or a 94% corn diet for 18 d. The other 6 treatments provided ad libitum access for 28 d to diets containing 94% corn, 94% wheat middlings (WM), 71% WM: 23% corn, 47% WM: 47% corn, 95% corn gluten feed, and 94% distillers dried grains with solubles (DDGS). At 28 d, all hens were fed a laying hen diet (16% CP), and production performance was measured for 40 wk. The 2 feed removal treatments resulted in total cessation of egg production within 6 d. Egg production of hens fed the 94% WM, 71% WM: 23% corn, corn, corn gluten feed, and 47% WM: 47% corn diets all decreased to 6% or less by d 12, 16, 19, 20, and 28, respectively. Egg production of hens fed DDGS never decreased below 18%. Body weight loss ranged from 10% (DDGS) to 26% (10-d feed removal), with the other treatments being similar at 17%. No consistent differences were observed among treatments throughout the 40-wk postmolt period for egg production, egg specific gravity, egg weight, egg yield, or feed efficiency. No differences were observed among feed removal treatments versus several nonfeed removal treatments for ovary and oviduct weights and blood heterophil:lymphocyte ratios during the molt period. In addition, interactive social behaviors were not different throughout the molt period between hens fed the 94% WM and those deprived of feed for 10 d. Our results indicate feeding WM, corn, corn gluten feed, and WM:corn diets are effective nonfeed removal methods for molting laying hens.

Four experiments were conducted to evaluate the effects of phosphorus nutrition on laying hens exposed to heat stress (HS). Hens were fed their respective diet for at least 3 wk prior to initiation of each experiment to allow the hens fed low-P diets to become P deficient. In most experiments, hens housed in non-HS conditions were pair-fed to the HS hens to maintain equal feed intake. In experiments 1 and 2, two levels of nonphytate P (NPP; deficient at 0.10 or 0.16% vs. control at 0.45%) and two temperatures (constant thermoneutral at 21 degrees C or cyclic HS up to 35 degrees C) were evaluated. Low NPP significantly reduced feed intake and hen-day egg production, but the cyclic heat treatment had no effect on hen performance. Experiment 3 was similar to experiments 1 and 2 except that constant HS was implemented. Both constant HS and low dietary NPP reduced feed intake and egg production, and there was no significant interaction between HS and dietary NPP level. In experiment 4, hens were fed 0.10 or 0.45% NPP diets and exposed to a more severe HS (38 degrees C) for 8 h. Hens fed the deficient NPP level showed a 16% incidence of severe heat distress (unable to stand, unresponsive). Our results generally indicated that there was no interaction between dietary NPP level and HS in laying hens. However, subjecting hens that had been fed a P-deficient diet to an acute HS of 38 degrees C did increase the incidence of severe heat distress.

Three chick assays were conducted to determine the effect of increasing dietary galactose (GAL), lactose (LAC), and Grobiotic-B70, a LAC fermentation product, on growth performance, toxicity, and energy utilization when fed to commercial broiler chicks. One-day-old male commercial broiler chicks were randomly assigned to treatments in each assay. In all assays, a 22% CP corn-soybean meal-dextrose basal diet containing a growth-promoting antibiotic (Bacitracin methylene disalicylate) was fed. In assay 1, GAL was added at 2, 4, 6, 10, or 15%. In assay 2, Grobiotic-B70 was added at 5%. In assay 3, GAL, LAC, and Grobiotic-B70 were each added at 2, 4, and 6%. All additions were made in place of dextrose, and diets were fed from 0 to 20 or 21 d of age. In assay 1, the 15% GAL treatment resulted in high mortality (27%) by d 3 and was terminated. The 10% GAL treatment also resulted in increased mortality, most of which occurred during the 7-to-14-d period. Inclusion of 2 and 4% GAL resulted in an improvement (P < 0.05) in growth compared to the basal diet. Inclusion of 2, 4, 6, and 10% GAL resulted in a significant linear decrease in ME n (r 2 = 0.85). In chick assay 2, 5% Grobiotic-B70 increased growth during the first 2 wk. In chick assay 3, 6% Grobiotic increased weight gain (P < 0.05) from 0 to 14 d, and addition of 2 or 4% GAL, 2 or 4% LAC, and 4 or 6% Grobiotic-B70 increased weight gain (P < 0.08) from 0 to 21 d. Our results indicate that levels of 10 to 15% GAL are toxic. In contrast, low levels of GAL and Grobiotic-B70, and possibly LAC, may increase growth of commercial broiler chicks.