The influence of substituting dietary peptide-bound with free amino acids on nitrogen metabolism and acid-base balance of broiler chickens depends on asparagine and glutamine supply.

Reducing dietary crude protein (CP) concentration while maintaining adequate amino acid (AA) supply by free AA inclusion can contribute to attenuate the negative environmental effects of animal farming. This study investigated upper limits of dietary free AA inclusions without undesirable effects including the dependence on asparagine (Asn) and glutamine (Gln) supply. Ten broilers were allocated to sixty-three metabolism units each and offered nine experimental diets from day (d) 7-21 (n 7). One diet (167 g CP/kg) contained 80 g soya protein isolate (SPI)/kg. In the other diets, 25, 50, 75 and 100 % of the digestible AA from SPI were substituted with free AA. Digestible Asn+aspartic acid (Asp) and Gln+glutamic acid (Glu) were substituted with Asp/Glu or 50/50 mixes of Asp/Asn and Glu/Gln, respectively. Total excreta were collected from d 11-14 and from d 18-21. Growth and nitrogen accretion were unaffected by 25 and 50 % substitution without and with free Asn/Gln, respectively, but decreased at higher substitution (P ≤ 0·024). Circulating concentrations of Asp, Glu and Gln were unaffected by treatment, while Asn decreased at substitution higher than 50 % when Asn/Gln were not provided (P ≤ 0·005). Blood gas analysis on d 21 indicated a compensated metabolic acidosis at substitution higher than 50 and 75 % without and with free Asn/Gln, respectively (P ≤ 0·017). Results suggest that adding Asn/Gln increased an upper limit for proportion of dietary free AA from 10 to 19 % of dietary CP and enabled higher free AA inclusion without affecting the acid-base balance.

Amino acid digestibility of insect meals and effects on key bacterial groups in excreta of caecectomised laying hens.

The chemical composition and amino acids (AA) digestibility were determined in insect meals from mealworms, crickets, black soldier fly (BSF) larvae and BSF prepupae, and soybean meal. Six caecectomised laying hens were individually housed in metabolism cages and fed either a basal diet or one of five assay diets. Diets and hens were arranged in a 6 × 6 Latin square design with 6 subsequent periods. In each period, the laying hens were fed their respective diet for 9 d, and excreta samples were quantitatively collected twice daily from day 5 to 8. On day 9, a sterile plastic bag was attached to the cloaca of each hen to collect excreta for microbiota analysis. The AA digestibility of the insect meals and soybean meal were calculated using a linear regression approach. Crude protein (CP) concentrations in crickets and mealworms were higher than the value in soybean meal, BSF prepupae and BSF larvae. Ether extract concentrations were high in the insect meals and low in the soybean meal. The digestibility of most essential AA in soybean meal was higher (p < 0.05) than in crickets and BSF prepupae and not different from AA digestibility in mealworms and BSF larvae (except for arginine and histidine). The gene copy number of Escherichia coli in excreta from hens fed with BSF prepupae was lower (p < 0.05) than those fed with BSF larvae, whereas the gene copy number of Bacillus spp. and Clostridium spp. in excreta from hens fed with crickets was lower (p < 0.05) than those fed with BSF larvae. In conclusion, the chemical composition and AA digestibility varied among insect meals based on insect species and life stage. The high level of AA digestibility of insect meals supports the assessment that insect meals are a suitable feed component for laying hens, but differences in AA digestibility should be considered in diet formulation.

Amino acid digestibility and metabolisable energy of spring and winter faba beans grown on two sites and effects of dehulling in caecectomised laying hens.

BACKGROUND: The variation in amino acid (AA) digestibility and metabolisable energy (MEN ) in four spring and four winter faba bean genotypes differing in vicine/convicine (V/C) concentrations grown on two sites was investigated in caecectomised LSL-Classic laying hens. Effects of dehulling one faba bean genotype were also examined. Diets containing one out of 17 faba bean variants each and a basal diet were fed to ten caecectomised laying hens in a row-column design to achieve five replicates per diet. RESULTS: Ranges and levels of digestibility of the hulled variants differed widely among AA with the lowest and highest range determined for Arg (90-93%) and Cys (-12-65%), respectively. MEN ranged between 10.3 and 12.3 MJ kg-1 dry matter. Lower MEN and digestibility of Cys, Glx, Phe, Pro, Tyr, and Val (P < 0.050) was determined for the winter genotypes grown in Nimtitz compared to the other variants. Digestibility of Ser was lower for the spring than for the winter genotypes (P < 0.050). Negative correlations with AA digestibility were determined for phytate, but not for tannin and V/C concentrations (P < 0.050). Negative correlations between tannin fractions and MEN were weak (P = 0.082-0.099). Dehulling increased MEN by 1.8 MJ kg-1 dry matter and raised the digestibility of Pro, His, and Glx (P < 0.050). CONCLUSIONS: The results indicated that the digestible AA and MEN supply of laying hens was increased by using low phytate faba beans while breeding for low V/C genotypes did not affect AA digestibility or MEN . Dehulling increased MEN and the digestibility of some AA. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Effect of microbial phytase supplementation on P digestibility in pigs: a meta-analysis.

The objectives of this meta-analysis were to determine to which extent phosphorus (P) digestibility and digestible P concentration in pig diets were increased by phytase supplementation and to quantify factors that potentially influence effects of phytase supplementation. A data set with a total of 547 data lines was compiled from 88 experiments published in 74 peer-reviewed papers between 2007 and April 2019. An exponential model was determined as more suitable to describe the response of P digestibility to phytase supplementation than a polynomial model. Phytase supplementation increased P digestibility by 25.6 percentage points (standard error (SE) = 1.54) to a plateau at 64.9% (SE = 1.82). The digestible P concentration was increased by phytase supplementation in the order of 1.01 g/kg (SE = 0.102) to a plateau at 2.62 g/kg (SE = 0.122). Goodness-of-fit criteria were R2 = 0.780 and root mean square error = 7.55% for P digestibility, and R2 = 0.691 and root mean square error = 0.48 g/kg for digestible P concentration. Consideration of further factors such as mineral P supplementation (yes or no), ad libitum vs. restrictive feeding, mixed diets vs. single feed ingredients, sex and age of pigs did not increase the accuracy of prediction in this data set. Some of these traits exhibited responses, but they likely are artefacts generated through the imbalanced structure of the data set. Effects of dietary total P, phytate (InsP6), InsP6-P to total P ratio, and Ca on the effect of supplemented phytase were not quantifiable. The present meta-analysis showed that responses to phytase supplementation can be well predicted although variation in P digestibility and digestible P concentration in the data set was high. Overall, predicted effects of phytase on P digestibility well corresponded to predictions made 25 years ago.

Evaluation of analytical and statistical approaches for predicting in vitro nitrogen solubility and in vivo pre-caecal crude protein digestibility of cereal grains in growing pigs.

Different analytical (enzyme system and near-infrared spectroscopy (NIRS)) and statistical (single and multiple regressions) approaches were used to predict in vivo standardized pre-caecal digestibility (PCD) of crude protein (CP) and amino acids (AA) in cereal grains for growing pigs as well as in vitro nitrogen (N) solubility. Furthermore, different chemical and physical characteristics were categorized (e.g. crude nutrients, AA, minerals, fibre components or combinations of these) and used for generating prediction equations. There were strong linear relationships (p < .05) between in vivo PCD of CP and essential AA and in vitro N solubility when grain species was considered as covariate in the model. Predicting in vivo PCD values using various chemical and physical characteristics produced inconsistent results among different grain species and AA and could therefore not be used for predicting PCD. It is possible to predict in vitro N solubility from chemical and physical characteristics for some grain species. However, the relationships between some of these categories and the in vitro N solubility were not consistent and not always causative or physiologically explainable. The R2 of NIRS for predicting in vitro N solubility was at a relatively high level (up to R2  = 0.80). This level of R2 indicates that a classification of the grain samples in, for example, high, medium and low in vitro N solubility levels is possible, but it does not allow for a quantitative prediction of the in vitro N solubility. In conclusion, the present database can be used for establishing a ranking of different cereal grain species for PCD of CP and essential AA values. However, it was not possible to create clear prediction equations for in vivo or in vitro digestibility values. Therefore, greater variation within grain species, for example due to different growing and harvesting conditions, is warranted for predicting PCD values of individual grain samples.

Very Low Crude Protein and Varying Glycine Concentrations in the Diet Affect Growth Performance, Characteristics of Nitrogen Excretion, and the Blood Metabolome of Broiler Chickens.

BACKGROUND: The minimum to which dietary crude protein (CP) level for broiler chickens can be reduced without decreasing growth and the glycine equivalent (Glyequi) concentration required are not known. The plasma metabolome might reflect dietary influences on physiological processes. OBJECTIVE: The aim of this study was to investigate the effect of 3 low CP levels with 4 Glyequi concentrations on growth and characteristics of nitrogen excretion, and to identify plasma metabolome variations. METHODS: Male Ross308 broiler chickens were provided 1 of 12 dietary treatments in 84 metabolism cages (10/cage) from days 7 to 21. Three diets with 163 (CP163), 147 (CP147), and 132 (CP132) g CP/kg were formulated, each containing 12, 15, 18, and 21 g Glyequi/kg. Essential amino acid concentrations were the same in all diets. Animals and feed were weighed on days 7 and 21 to determine average daily gain (ADG) and gain:feed ratio (G:F). Excreta were collected from days 18 to 21 to analyze nitrogenous components, and blood was obtained on day 21 to conduct a metabolome analysis. RESULTS: Two-factor ANOVA showed significant interaction effects for ADG, G:F, and nitrogen efficiency (P < 0.001). Reduction of CP decreased ADG and G:F, and increased nitrogen efficiency. Glyequi supplementation increased ADG (by 7.9 g/d) and G:F (by 0.07 g/g) at CP132. The ADG (by 2.4 g/d) at CP147 and G:F (by 0.02 g/g) at CP147 and CP163 increased up to 15 g Glyequi/kg. Multivariate statistical analysis showed an influence of Glyequi on plasma acylcarnitine and lysophosphatidylcholine concentrations, and a decrease of plasma phosphatidylcholine and sphingomyelin concentrations with reduced CP. CONCLUSIONS: These results suggest that a nutrient other than Glyequi limited growth when CP was reduced from CP163 to CP147, and that the response of broiler chickens to Glyequi is dependent on the dietary CP level. Plasma metabolites indicate dietary influences on the physiological state of the animals.

Effect of amino acid deficiency on precaecal amino acid digestibility in broiler chickens.

In this study, we determined whether deficient dietary amino acid (AA) concentrations influence the precaecal (pc) AA digestibility when determined using the regression approach. We mixed two basal diets. Basal diet 1 was deficient in essential AAs, whereas adequate AA concentrations were ensured in basal diet 2 by adding free AAs. Rapeseed cake and full-fat soya beans as test ingredients were included in the basal diets at levels of 100 and 200, and 150 and 300 g/kg, respectively, at the expense of maize starch. Each diet was tested with six replicates of 10 broiler chickens each. The feed intake of the chickens that were fed diets based on basal diet 2 was similar, whereas the feed intake of the chickens that were fed diets based on basal diet 1 differed considerably. The numerical differences in pc AA digestibility determined with basal diet 1 or 2 ranged from 2.6 percentage points to 20.8 percentage points in rapeseed cake and from 0.5 percentage points to 15.2 percentage points in soya beans. Across all measured AAs, the average differences were 10.1 percentage points and 5.4 percentage points in rapeseed cake and soya beans, respectively. The differences in the estimated pc AA digestibility between the basal diets were probably caused by different basal endogenous AA losses in the digesta between treatments as a consequence of different feed intake. Adequate AA concentrations and test ingredient levels that are specifically adjusted to avoid a negative effect on feed intake are recommended for future studies.

Influence of feed provisioning prior to digesta sampling on precaecal amino acid digestibility in broiler chickens.

A regression approach was applied to determine the influence of feed provisioning prior to digesta sampling on precaecal (pc) amino acid (AA) digestibility in broiler chickens. Soybean meal was used as an example test ingredient. Five feed-provisioning protocols were investigated, four with restricted provision and one with ad libitum provision. When provision was restricted, feed was provided for 30 min after a withdrawal period of 12 h. Digesta were sampled 1, 2, 4 and 6 h after feeding commenced. A diet containing 300 g maize starch/kg was prepared. Half or all the maize starch was replaced with soybean meal in two other diets. Average pc digestibility of all determined AA in the soybean meal was 86% for the 4 and 6-h protocols and 66% and 60% for the 2 and 1-h protocols, respectively. Average pc AA digestibility of soybean meal was 76% for ad libitum feed provision. Feed provisioning also influenced the determined variance. Variance in digestibility ranked in magnitude 1 h > ad libitum > 2 h > 6 h > 4 h for all AA. Owing to the considerable influence of feed-provisioning protocols found in this study, comparisons of pc AA digestibility between studies applying different protocols prior to digesta sampling must be treated with caution. Digestibility experiments aimed at providing estimates for practical feed formulation should use feed-provisioning procedures similar to those used in practice.

Effect of nitrogen fertilisation on the amino acid digestibility of different triticale genotypes in caecectomised laying hens.

BACKGROUND: The influence of nitrogen fertilisation and genotype on the amino acid (AA) digestibility of triticale grain was investigated in caecectomised laying hens. Three genotypes, Grenado, EAW6002 and Lasko, were cultivated with and without nitrogen fertilisation at the end of the heading stage. The six triticale variants as well as a basal diet were each used to feed seven laying hens in a 7 × 7 Latin square design. RESULTS: Nitrogen fertilisation influenced the digestibility of Cys, Glu, Phe and Ser in some triticale genotypes and reduced Ala, Ile, Lys, Met and Val digestibility in all genotypes (P < 0.05). Nitrogen fertilisation increased the concentration of all AAs in the grain. Consequently, the concentration of digestible AAs in the grains was increased for most AAs upon nitrogen fertilisation. Overall, Lys had the lowest digestibility, whereas that of Glu and Pro was the highest. For the triticale genotypes, the level of AA digestibility was highest for EAW6002 followed by Lasko and Grenado, with significant differences (P < 0.05) between genotypes for some but not all AAs. CONCLUSION: The results indicated that the accuracy of the digestible AA supply for hen feeding might benefit from considering fertilisation and genotype-specific digestibility data in feed formulation. © 2016 Society of Chemical Industry.

Variation in chemical composition and physical characteristics of cereal grains from different genotypes.

Genotypes of cereal grains, including winter barley (n = 21), maize (n = 27), oats (n = 14), winter rye (n = 22), winter triticale (n = 21) and winter wheat (n = 29), were assayed for their chemical composition and physical characteristics as part of the collaborative research project referred to as GrainUp. Genotypes of one grain species were grown on the same site, except maize. In general, concentrations of proximate nutrients were not largely different from feed tables. The coefficient of variation (CV) for the ether extract concentration of maize was high because the data pool comprised speciality maize bred for its high oil content. A subset of 8 barley, 20 rye, 20 triticale and 20 wheat samples was analysed to differ significantly in several carbohydrate fractions. Gross energy concentration of cereal grains could be predicted from proximate nutrient concentration with good accuracy. The mean lysine concentration of protein was the highest in oats (4.2 g/16 g N) and the lowest in wheat (2.7 g/16 g N). Significant differences were also detected in the concentrations of macro elements as well as iron, manganese, zinc and copper. Concentrations of arsenic, cadmium and lead were below the limit of detection. The concentration of lower inositol phosphates was low, but some inositol pentaphosphates were detected in all grains. In barley, relatively high inositol tetraphosphate concentration also was found. Intrinsic phytase activity was the highest in rye, followed by triticale, wheat, barley and maize, and it was not detectable in oats. Substantial differences were seen in the thousand seed weight, test weight, falling number and extract viscoelasticity characteristics. The study is a comprehensive overview of the composition of different cereal grain genotypes when grown on the same location. The relevance of the variation in composition for digestibility in different animal species will be subject of other communications.

Effects of carriers for oils in compound feeds on growth performance, nutrient digestibility, and gut microbiota in broiler chickens.

Carrier materials for oils in compound feeds may be used in animal nutrition to supply liquid feed additives. However, implications of such carriers for the digestibility of the contained oil are unknown. This study investigated the potential of oil carriers in compound feed and their effect on performance, metabolizable energy, fatty acid (FA) retention, amino acid (AA) digestibility, and gut microbiota in broiler chickens. Six experimental diets were formulated following a 2 × 3 factorial arrangement with 20 g/kg or 40 g/kg of rapeseed oil supplied with no carrier or bound in a silica-based (SC) or lignocellulose-based (LC) carrier in a 1:1 mass ratio. The diets were assigned to 48 metabolism units with 15 animals each based on a randomized complete block design and fed from d 18 to 28 of the trial. Total excreta were collected from d 24 to 27 and used to determine total tract retention (TTR) of FA and MEn. On d 28, AA digestibility both by the distal half of the jejunum and the distal half of the ileum was determined, and microbiota of ileal and cecal digesta was analyzed using 16S ribosomal RNA sequencing. There were significant interactions for ADG, ADFI, the gain:feed ratio (G:F), MEn, and the TTR of crude fat and most fatty acids (P ≤ 0.046) except for C18, C18:2, and C22:0. Addition of SC decreased ADG, ADFI, and G:F (P < 0.001), while LC at 40 g/kg oil inclusion increased G:F and MEn (P < 0.001) for both inclusion levels. The TTR of crude fat and the FA C18:1, C18:2, C18:3, and C22:0 was increased by the addition of SC (P ≤ 0.016), while LC increased the TTR of the FA C18:1 and C18:2 as well as the TTR of C18:3 at 20 g/kg oil inclusion (P ≤ 0.016). Adding SC and LC increased the digestibility of 7 and 2 AA by the distal half of the jejunum, respectively, and the digestibility of 8 and 13 AA by the distal half of the ileum, respectively (P ≤ 0.039). The ß-diversity and abundance of some taxa were altered by addition of LC and SC in the ceca while no treatment effect on the ileal microbiota was found. The results give no indication of an incomplete release of the oil from the carriers because the TTR of most FA was increased upon addition of SC and LC. LC may be used to supply liposoluble feed additives without drawbacks for nutrient digestibility and growth while SC requires further examination.

Responses of the blood acid-base balance and blood plasma metabolomics of broiler chickens after change to diets with high free amino acid levels.

Free amino acids (AA) are needed to fulfill the AA requirements of broiler chickens in diets low in CP. This study investigated whether the acid-base balance and the blood plasma metabolome are affected immediately after a change to diets with high free AA levels. Male broiler chickens received a starter diet with 164 g CP/kg and 80 g soy protein isolate/kg until d 7 post-hatch. From this day on, birds were offered a diet almost identical to the starter diet (0FAA) or 2 diets with 50% (50FAA) or 100% (100FAA) of the digestible AA from soy protein isolate substituted with free AA. Blood was sampled to determine the acid-base status and for untargeted metabolomics analysis on d 0, 1, 2, 4, 7, and 14 and d 1, 7, and 14 after diet change, respectively (n = 14 birds/treatment). Compared to 0FAA, blood pH was decreased on d 4 and 7 for 100FAA and on d 4 for 50FAA (P ≤ 0.019). On d 4, 7, and 14, bicarbonate, base excess, and total carbon dioxide were lower for 100FAA than for 0FAA (P ≤ 0.006). The partial pressure of carbon dioxide was higher for 50FAA than for 0FAA on d 4 (P = 0.047). Compared to 0FAA, chloride was higher for 100FAA on d 1, 2, 4, 7, and 14, and for 50FAA on d 1, 2, and 4 (P ≤ 0.030). In the metabolomics assay, 602, 463, and 302 metabolites were affected by treatment on d 1, 7, and 14, respectively (P < 0.050), but they did not indicate that metabolic pathways were affected. Flavonoids were the most consistently affected category of metabolites. The results indicated a metabolic acidosis for 100FAA from d 4 to 7 and a respiratory acidosis for 50FAA on d 4 after diet change. These types of acidosis were compensated later on in the experiment. The metabolomics analysis did not indicate that high free AA inclusion affected metabolic pathways.

True mineral digestibility in C57Bl/6J mice.

Data on mineral digestibility is key to understand mineral homeostasis and refine the recommendations for the dietary intake of these nutrients. In farm animals and pets, there is plenty of data on mineral digestibility and influencing factors. In laboratory mice, however, there is a lack of information on mineral digestibility under maintenance conditions, although this should be the basis for studies on mineral homeostasis under experimental conditions. The aim of the present study was to analyse data on intake, faecal excretion, and apparent digestibility of calcium, phosphorus, sodium, potassium, and magnesium in C57BL/6J mice fed different maintenance diets with varying voluntary dry matter intake. Lucas-tests were used to quantify true digestibility and describe correlations between dietary intake and excretion/absorption of the nutrients. Calcium, phosphorus, and magnesium showed a linear correlation between intake and faecal excretion (R2: 0.77, 0.93 and 0.91, respectively). Intake and apparently digested amounts of sodium and potassium were correlated linearly (R2: 0.86 and 0.98, respectively). These data show that intake is the major determinant of absorption in the minerals listed above. Faecal calcium and phosphorus excretion were correlated as well (R2 = 0.75).

Effect of low-temperature drying on the nitrogenous compounds and inositol phosphates in broiler chickens and cecectomized laying hen excreta.

We investigated how the chemical composition of broiler chicken and cecectomized laying hen excreta is affected by drying in a forced-air drying chamber at low temperatures. Excreta that was immediately frozen after voiding provided the reference values. The excreta were dried in drying chambers for 4 hr, 6 hr, and 12 hr at 23°C or 33°C in the broiler experiment and 19°C or 29°C in the cecectomized laying hen experiment. The total N and inositol phosphate concentrations in the excreta of broiler chickens and cecectomized laying hens were not influenced (p > .050), except for one inositol tetrakisphosphate isomer (p = .026) in broilers. Compared to fresh excreta, drying did not affect the ammonia concentrations in the cecectomized laying hen experiment (p > .050), but the ammonia concentration was lower when dried for 12 hr at 33°C in the broiler experiment (p = .002). Amino acid concentrations in cecectomized laying hen excreta decreased until 4 hr of drying and then increased at both drying temperatures (p < .001). The results indicate that the applicability of drying poultry excreta at low temperatures in forced-air drying chambers to determine the chemical compound concentrations is trait-dependent. Future studies are necessary to investigate whether these results are also dependent upon the amount of excreta stored in the drying chambers.

Phytase Supplementation Effects on Amino Acid Digestibility in Broiler Chickens are Influenced by Dietary Calcium Concentrations but not by Acid-Binding Capacity.

BACKGROUND: Responses to dietary calcium (Ca) and supplemented phytase on prececal amino acid digestibility (pcAAD) in broiler chickens vary among studies. The variation may arise from the dietary acid-binding capacity (ABC) that influences the activity of enzymes in the digestive tract and from microbial activity. OBJECTIVE: This study aimed to investigate whether the ABC influences phytase effects on pcAAD and whether microbial activity contributes to this. METHODS: Male Ross 308 broiler chickens were provided 1 of 12 diets in 72 pens (15/pen) from day 16 of age until the end of the experiment on days 21 or 22. In a 3 × 2 × 2-factorial arrangement, the ABC was varied by replacing calcium carbonate (CaCO3) with Ca-formate or by adding formic acid to CaCO3-containing diets, and contained 5.6 or 8.2 g Ca/kg and 0 or 1500 phytase units/kg. The ileum content was collected for pcAAD measurement and microbial community composition was used to investigate whether changes in pcAAD are related to the microbiota. RESULTS: Three-factor ANOVA showed that reducing the ABC increased pcAAD (average 1.1 percentage points) and no significant interaction of the ABC with Ca concentration and phytase supplementation including 3-way interactions. Without phytase, increasing dietary Ca concentration decreased pcAAD (average 3.1 percentage points). Phytase supplementation increased pcAAD (average 2.1 and 5.0 percentage points at low and high Ca concentrations, respectively), to reach the same level for both Ca concentrations. Microbial functional predictions pointed towards an influence of the microbiota in the crop and ileum content on amino acid concentrations, as indicated by different relative abundances of predicted genes related to amino acid biosynthesis, degradation, and metabolism. CONCLUSIONS: Dietary Ca concentrations but not the ABC modulates the effect of supplemented phytase on pcAAD in broiler chickens. The microbiota might contribute to differences in pcAAD by changing the amino acid composition of the digesta. The extent of this effect is still unknown.

Effects of calcium level and source, formic acid, and phytase on phytate degradation and the microbiota in the digestive tract of broiler chickens.

BACKGROUND: Diet acidification, dietary calcium (Ca) level, and phytase supplementation are known influences on the microbial community in the digestive tract and on phosphorus (P) utilization of broiler chickens. Effects of dietary factors and microbiota on P utilization may be linked because microorganisms produce enzymes that release P from phytate (InsP6), the main source of P in plant feedstuffs. This study aimed to detect linkages between microbiota and InsP6 degradation by acidifying diets (i.e., replacing Ca carbonate (CaCO3) by Ca formate or adding formic acid to CaCO3-containing diets), varying Ca levels, and supplementing phytase in a three-factorial design. We investigated i) the microbial community and pH in the digestive tract, ii) prececal (pc) P and Ca digestibility, and iii) InsP6 degradation. RESULTS: All factors under investigation influenced digesta pH and the microbiota composition. Predicted functionality and relative abundance of microorganisms indicated that diets influenced the potential contribution of the microbiota on InsP degradation. Values of InsP6 degradation and relative abundance of the strains Lactobacillus johnsonii and Lactobacillus reuteri were correlated. Phytase supplementation increased pc InsP6 disappearance, with differences between Ca levels, and influenced concentrations of lower inositol phosphate isomers in the digestive tract. Formic acid supplementation increased pc InsP6 degradation to myo-inositol. Replacing CaCO3 by Ca-formate and the high level of these Ca sources reduced pc InsP6 disappearance, except when the combination of CaCO3 + formic acid was used. Supplementing phytase to CaCO3 + formic acid led to the highest InsP6 disappearance (52%) in the crop and increased myo-inositol concentration in the ileum digesta. Supplementing phytase leveled the effect of high Ca content on pc InsP6 disappearance. CONCLUSIONS: The results point towards a contribution of changing microbial community on InsP6 degradation in the crop and up to the terminal ileum. This is indicated by relationships between InsP6 degradation and relative abundance of phosphatase-producing strains. Functional predictions supported influences of microbiota on InsP6 degradation. The extent of such effects remains to be clarified. InsP6 degradation may also be influenced by variation of pH caused by dietary concentration and solubility of the Ca in the feed.

Relative phytase efficacy values as affected by response traits, including ileal microbiota composition.

The objective of this study was to compare the effects of graded inclusions of 2 phytase products and a mineral P source in broiler chickens using different response traits, including ileum microbiota composition. Eleven experimental diets were used. These were a low-P basal diet and diets supplemented with increasing levels of dicalcium phosphate (DCP), Natuphos E 5000 G (NE), or Natuphos 5000 G (N). The performance traits, prececal P digestibility, and tibia and foot ash results were subjected to regression analysis and slope ratios were used to compare the supplements based on the measured evaluation traits. In the microbiota analysis, total nucleic acids were extracted and the 16S rRNA gene was targeted for use in the amplicon sequencing process. Phylogenetic analysis was performed using Mothur, followed by a multivariate statistical analysis. The various response traits caused different estimates of relative efficacy. The mean results of all the response traits showed that a 1.75-fold increase in the activity of N was needed to achieve the same response as NE and the variability among the detected traits ranged from 1.59 (prececally digestible P intake) to 1.91 (amount of tibia ash). The mean slope ratio between DCP and NE was 311 and varied between 208 (ADG) and 349 (foot ash concentration). The mean slope ratio for phytase N with DCP was 552 and varied from 357 (ADG) to 640 (tibia ash concentration). The ileum microbiota composition was not different among the diets. A similar composition was driven in the abundance of Lactobacillus crispatus, Lactobacillus salivarius, and Lactobacillus gallinarum. The results suggest that different response traits cause markedly different estimates of relative phytase efficacy.

Impact of genomic risk factors on outcome after hematopoietic stem cell transplantation for patients with chronic myeloid leukemia.

BACKGROUND: Non-HLA gene polymorphisms have been shown to influence outcome after allogeneic hematopoietic stem cell transplantation. Results were derived from heterogeneous, small populations and their value remains a matter of debate. DESIGN AND METHODS: In this study, we assessed the effect of single nucleotide polymorphisms in genes for interleukin 1 receptor antagonist (IL1RN), interleukin 4 (IL4), interleukin 6 (IL6), interleukin 10 (IL10), interferon (IFNG), tumor necrosis factor (TNF) and the cell surface receptors tumor necrosis factor receptor II (TNFRSFIB), vitamin D receptor (VDR) and estrogen receptor alpha (ESR1) in a homogeneous cohort of 228 HLA identical sibling transplants for chronic myeloid leukemia. Three good predictors of overall survival, identified via statistical methods including Cox regression analysis, were investigated for their effects on transplant-related mortality and relapse. Predictive power was assessed after integration into the established European Group for Blood and Marrow Transplantation (EBMT) risk score. RESULTS: Absence of patient TNFRSFIB 196R, absence of donor IL10 ATA/ACC and presence of donor IL1RN allele 2 genotypes were associated with increased transplantation-related mortality and decreased survival. Application of prediction error and concordance index statistics gave evidence that integration improved the EBMT risk score. CONCLUSIONS: Non-HLA genotypes were associated with survival after allogeneic hematopoietic stem cell transplantation. When three genetic polymorphisms were added into the EBMT risk model they improved the goodness of fit. Non-HLA genotyping could, therefore, be used to improve donor selection algorithms and risk assessment prior to allogeneic hematopoietic stem cell transplantation.

Effects of supplemented nonessential amino acids and nonprotein nitrogen on growth and nitrogen excretion characteristics of broiler chickens fed diets with very low crude protein concentrations.

Reducing dietary CP for broiler chickens below a certain threshold results in decreased growth, even when the supply of essential amino acids and glycine equivalent (Glyequi) is adequate, probably because other nonessential amino acids (neAA) are growth-limiting. Nonprotein nitrogen (NPN) might be used for the synthesis of neAA. Therefore, the effects of specific neAA and ammonium chloride (NH4Cl) supplementation on the growth and N-excretion characteristics of broiler chickens were investigated. Nine male Ross 308 broiler chickens were kept in each of 81 metabolism units from day 7 to 21 and received 1 of 9 diets in 9 replicates in a one-factorial arrangement of treatments. Two diets with different neAA concentrations, except for Glyequi, were mixed resulting in CP levels of 180 (CP180) and 160 (CP160) g/kg. In six other diets, CP160 was supplemented with either l-Ala, l-Pro, l-Asp, a mix of l-Asp and l-Asn·H2O, l-Glu, or a mix of l-Glu and l-Gln to achieve concentrations of the respective neAA as formulated in CP180. In a further diet, NH4Cl was added to CP160 to achieve the CP concentration of CP180. The ADG and gain:feed ratio (G:F) from day 7 to 21 were highest at CP180. Reduced neAA concentrations in CP160 decreased ADG and G:F. Supplementation of Asp+Asn, Glu, and Glu+Gln to CP160 increased ADG and G:F, but not to the level found for CP180. Compared with CP160, addition of Asp increased G:F but not ADG. Supplementation of Asp+Asn caused higher ADG and G:F than supplementation of Asp alone. The N-utilization efficiency was highest at CP160 and at CP160 supplemented with Ala, Pro, and Glu. Lower N-utilization efficiency was found at CP180 than at CP160, without and with supplemented neAA. The treatment containing NH4Cl presented the lowest ADG, G:F, and N-utilization efficiency. These results showed that individual supplementation of Asp+Asn, Glu, and Glu+Gln partly compensates for the growth-reducing effects of very low CP diets. Supplementation of NH4Cl as NPN source is not suitable for broiler chickens.

Phytase supplementation effects on amino acid digestibility depend on the protein source in the diet but are not related to InsP6 degradation in broiler chickens.

The objective was to determine phytase effects on prececal amino acid (AA) digestibility and phytate (InsP6) breakdown when different oilseed meals were used in broiler chicken diets. The study included 14 diets: a corn-soybean meal (SBM) basal diet and 6 diets that contained SBM, rapeseed meal (RSM), and sunflower meal (SFM) with 2 inclusion levels at the expense of corn starch (150 and 300 g/kg SBM or SFM, or 100 and 200 g/kg RSM). Each diet was mixed with or without a phytase supplement of 1,500 FTU/kg. Diets were provided to broilers for 5 D. Digesta from the posterior half of the ileum were collected on day 21. The average essential AA digestibility, calculated by a regression approach, without and with phytase was 84 and 85% (SBM), 74 and 77% (SFM), and 66 and 73% (RSM), respectively. In the diets, phytase effects on AA digestibility were lower owing to other protein sources also present in the diet, but significant. Prececal InsP6 disappearance was significantly affected by interactions between oilseed meal, inclusion level, and phytase supplementation. Overall, prececal InsP6 disappearance was higher in SBM diets (52%) than in SFM diets (38%) and intermediate in RSM diets (43%). Across diets, phytase supplementation effects on prececal InsP6 degradation linearly increased with the InsP6 concentration of the diet up to 12 g/kg DM. The only exception from linearity was the diet with the high inclusion of SFM, which contained 15.9 g InsP6/kg DM. In the ileal content, the concentration of myo-inositol was significantly increased by phytase supplementation, and this effect was highest in the diets that contained SBM as the only oilseed meal. Concentrations of lower inositol phosphates were increased by phytase supplementation, and this effect was most remarkable for Ins(1,2,3,4)P4 and inositol tetrakisphosphates. The study showed that phytase effects on AA digestibility varied among the 3 tested oilseed meals, but these differences were not detectable in the diets containing these meals. Although phytase effects on ileal content of InsP6 and its degradation products were substantial, they were not related to the effects on AA digestibility.