An in vitro model for caecal proteolytic fermentation potential of ingredients in broilers.

Fermentation of protein in the caeca of chickens may lead to the production of potentially detrimental metabolites, which can reduce gut health. A poor precaecal digestion is expected to increase protein fermentation (PF), as more proteins are likely to enter the caeca. It is unknown if the undigested protein that enters the caeca differs in fermentability depending on their ingredient source. In order to predict which feed ingredients increase the risk of PF, an in vitro procedure was developed, which simulates the gastric and enteric digestion, subsequent caecal fermentation. After digestion, amino acids and peptides smaller than 3.5 kD in the soluble fraction were removed by means of dialysis. These amino acids and peptides are assumed to be hydrolysed and absorbed in the small intestine of poultry and therefore not used in the fermentation assay. The remaining soluble and fine digesta fractions were inoculated with caecal microbes. In chicken, the soluble and fine fractions enter the caeca, to be fermented, while insoluble and coarse fractions bypass them. The inoculum was made N-free to ensure bacteria would require the N from the digesta fractions for their growth and activity. The gas production (GP) from the inoculum, therefore, reflected the ability of bacteria to use N from substrates and was an indirect measure for PF. The Maximum GP rate of ingredients averaged 21.3 ± 0.9 ml/h (mean ± SEM) and was in some cases more rapid than the positive control (urea, maximum GP rate = 16.5 ml/h). Only small differences in GP kinetics were found between protein ingredients. Branched-chain fatty acids and ammonia concentrations in the fermentation fluid after 24 hours showed no differences between ingredients. Results indicate that solubilised undigested proteins larger than 3.5 kD are rapidly fermented independent of its source when an equal amount of N is present.

Vitamin E and beta-carotene status of dairy cows: a survey of plasma levels and supplementation practices.

Culling rate in dairy cattle has increased considerably, thereby reducing cows longevity and raising sustainability concerns worldwide. In the last decades, feeding systems have changed towards larger inclusion of preserved forages and reduced fresh herbage, which may limit vitamin E and beta-carotene dietary supply to dairy cows. Because of higher oxidative stress, engendered by greater milk production of modern genetics, the requirement for these nutrients is increased. Therefore, this study aimed to assess the current status of vitamin E and beta-carotene of commercial dairy cows. Blood vitamin E and beta-carotene concentrations were measured in 2 467 dairy cows from 127 farms in Belgium, Germany, Iberia and The Netherlands, that were visited once. Five cows were randomly selected per lactation stage per farm: Dry (between 30 and 1 day(s) before calving), Very-early (from calving until 15 days in milk (DIM)), Early (between 16 and 119 DIM), and Mid-late (from 120 DIM onwards). In addition, a survey was conducted to retrieve data on vitamin E and beta-carotene supplementation and feeding practices. Vitamin E and beta-carotene blood concentrations dropped considerably around calving. Among all surveyed cows, more than 75 and 44% were deficient in vitamin E and beta-carotene (i.e., blood concentration below 3.0 and 3.5 mg/l, respectively). Of the Very-early group, more than 97 and 78% of the cows were deficient in vitamin E and beta-carotene, respectively, with respective blood concentrations of 1.15 and 2.71 mg/l, which was significantly lower than the other lactation stages. Vitamin E and beta-carotene blood concentrations, as well as their supplementation levels, significantly varied among countries. Vitamin E and beta-carotene blood concentrations were positively related to the total estimated daily intakes of vitamin E and beta-carotene. Therefore, blood concentrations of vitamin E and beta-carotene depend on their respective level of intake, which is generally below recommendations and varies greatly between countries. Supplementation could contribute to provide cows with adequate amounts of vitamin E and beta-carotene all along the lactation, to ensure their lifetime performance and improve their fertility.

The impact of 1-year vitamin D supplementation on vitamin D status in athletes: a dose-response study.

BACKGROUND/OBJECTIVES: To assess the prevalence of vitamin D deficiency in Dutch athletes and to define the required dosage of vitamin D3 supplementation to prevent vitamin D deficiency over the course of a year. SUBJECTS/METHODS: Blood samples were collected from 128 highly trained athletes to assess total 25(OH)D concentration. Of these 128 athletes, 54 male and 48 female athletes (18-32 years) were included in a randomized, double blind, dose-response study. Athletes with either a deficient (<50 nmol/l) or an insufficient (50-75 nmol/l) 25(OH)D concentration were randomly assigned to take 400, 1100 or 2200 IU vitamin D3 per day orally for 1 year. Athletes who had a total 25(OH)D concentration above 75 nmol/l at baseline continued with the study protocol without receiving vitamin D supplements. Serum total 25(OH)D concentration was assessed every 3 months, as well as dietary vitamin D intake and sunlight exposure. RESULTS: Nearly 70% of all athletes showed an insufficient (50-75 nmol/l) or a deficient (<50 nmol/l) 25(OH)D concentration at baseline. After 12 months, serum 25(OH)D concentration had increased more in the 2200 IU/day group (+50±27 nmol/l) than the sufficient group receiving no supplements (+4±17 nmol/l; P<0.01) and the 1100 IU/day group (+25±23 nmol/l; P<0.05). Supplementation with 2200 IU/day vitamin D resulted in a sufficient 25(OH)D concentration in 80% of the athletes after 12 months. CONCLUSIONS: Vitamin D deficiency is highly prevalent in athletes. Athletes with a deficient or an insufficient 25(OH)D concentration can achieve a sufficient 25(OH)D concentration within 3 months by taking 2200 IU/day.

Changes in myonuclear domain size do not precede muscle hypertrophy during prolonged resistance-type exercise training.

AIM: Muscle fibre hypertrophy is accompanied by an increase in myonuclear number, an increase in myonuclear domain size or both. It has been suggested that increases in myonuclear domain size precede myonuclear accretion and subsequent muscle fibre hypertrophy during prolonged exercise training. In this study, we assessed the changes in muscle fibre size, myonuclear and satellite cell content throughout 12 weeks of resistance-type exercise training in young men. METHODS: Twenty-two young men (23 ± 1 year) were assigned to a progressive, 12-weeks resistance-type exercise training programme (3 sessions per week). Muscle biopsies from the vastus lateralis muscle were taken before and after 2, 4, 8 and 12 weeks of exercise training. Muscle fibre size, myonuclear content, myonuclear domain size and satellite cell content were assessed by immunohistochemistry. RESULTS: Type I and type II muscle fibre size increased gradually throughout the 12 weeks of training (type I: 18 ± 5%, type II: 41 ± 6%, P < 0.01). Myonuclear content increased significantly over time in both the type I (P < 0.01) and type II (P < 0.001) muscle fibres. No changes in type I and type II myonuclear domain size were observed at any time point throughout the intervention. Satellite cell content increased significantly over time in both type I and type II muscle fibres (P < 0.001). CONCLUSION: Increases in myonuclear domain size do not appear to drive myonuclear accretion and muscle fibre hypertrophy during prolonged resistance-type exercise training in vivo in humans.

Vitamin D: do we get enough? A discussion between vitamin D experts in order to make a step towards the harmonisation of dietary reference intakes for vitamin D across Europe.

UNLABELLED: On September 29, 2011, acknowledged experts in the field of vitamin D, mainly European, were brought together in order to discuss the recent scientific advances in relation to vitamin D: the current requirements and associations with various health outcomes. In this article, the discussions resulting from the meeting are summarized. INTRODUCTION: Several groups at risk for developing vitamin D insufficiency have been identified. Accordingly, reviews indicate that a significant percentage of the population worldwide have serum 25-hydroxyvitamin D levels below 50 nmol/l. In addition to the role of vitamin D in bone health, recent studies suggest that it may play a pivotal role in other systems, e.g., the cardiovascular system, pancreas, muscle, immune system and brain. Most evidence, however, is obtained from observational studies and yet inconclusive. METHODS: To exchange and broaden knowledge on the requirements for vitamin D and its effect on various health outcomes, a workshop entitled "Vitamin D Expert Meeting: Do we get enough?", was organized. RESULTS: Despite low vitamin D levels worldwide, consensus on the definition of deficiency is not yet reached. In order to define cut-off points for vitamin D whilst taking into account extraskeletal health effects, randomized controlled trials in these fields are warranted. The experts do emphasize that there is evidence to suggest an important role for vitamin D in the maintenance of optimal bone health at all ages and that vitamin D supplementation, in most studies co-administered with calcium, reduces fracture risk in the senior population. CONCLUSION: To reach a serum 25-hydroxyvitamin D level of 50 nmol/l older adults aged ≥65 years are therefore recommended to meet a mean daily vitamin D intake of 20 µg (800 IU), which is best achieved with a supplement.

Effects of low doses of casein hydrolysate on post-challenge glucose and insulin levels.

BACKGROUND: Ingestion of high doses of casein hydrolysate stimulates insulin secretion in healthy subjects and patients with type 2 diabetes. The effects of low doses have not been studied. The aim of this study was to assess the effect of lower doses of a casein hydrolysate on the glucose and insulin responses to an oral glucose tolerance test in patients with type 2 diabetes. METHODS: In this randomized, placebo-controlled, double-blind study, thirteen patients with type 2 diabetes (age: 58±1 years) were studied. Glucose, insulin and C-peptide responses were determined after the oral administration of 0 (control), 6 or 12 g protein hydrolysate in combination with 50 g carbohydrate. RESULTS: Twelve grams of casein hydrolysate, but not 6g, elevated insulin levels and decreased glucose levels post-challenge. These changes over time were not large enough to also affect the total area under the curve of glucose and insulin. C-peptide levels did not change after both treatments. CONCLUSION: Ingestion of six grams of casein hydrolysate did not affect glucose or insulin responses. Intake of 12 g of casein hydrolysate has a small positive effect on post-challenge insulin and glucose levels in patients with type 2 diabetes.

The production of intrinsically labeled milk protein provides a functional tool for human nutrition research.

Oral or intravenous administration of labeled, free amino acids does not allow the direct assessment of protein digestion and absorption kinetics following dietary protein intake. Consequently, dietary protein sources with labeled amino acids incorporated within the protein are required. The aim of this study was to produce milk proteins intrinsically labeled with l-[1-(13)C]phenylalanine that would allow the assessment of protein digestion and absorption kinetics and the subsequent muscle protein synthetic response to dietary protein intake in vivo in humans. Two Holstein cows (body weight of 726 +/- 38 kg) were continuously infused with l-[1-(13)C]phenylalanine at 402 micromol/min for 44 to 48 h, during and after which plasma samples and milk were collected. After milk protein separation, casein was used in a subsequent human proof-of-principle experiment. Two healthy males (aged 61 +/- 1 yr; body mass index of 22.4 +/- 0.1 kg/m(2)) ingested 35 g of casein highly enriched with [1-(13)C] phenylalanine. Plasma samples were collected at regular intervals, and skeletal muscle biopsies were collected before and 6 h after casein ingestion. In the initial experiment, a total of 5.83 kg of l-[1-(13)C]phenylalanine-enriched milk protein (casein enrichment was 29.4 molar percent excess) was collected during stable isotope infusion in the cows. In the proof-of-principle study, ingestion of 35 g of intrinsically labeled casein resulted in peak plasma l-[1-(13)C]phenylalanine enrichments within 90 min after protein ingestion (9.75 +/- 1.47 molar percent excess). Skeletal muscle protein synthesis rates calculated over the entire 6-h period averaged 0.058 +/- 0.012%/h. The production of intrinsically labeled milk protein is feasible and provides dietary protein that can be used to investigate protein digestion and absorption and the subsequent muscle protein synthetic response in vivo in humans.

Effect of graded doses and a high dose of microbial phytase on the digestibility of various minerals in weaner pigs.

An experiment with 224 weaner pigs (initial BW of 7.8 kg) was conducted to determine the effect of dose of dietary phytase supplementation on apparent fecal digestibility of minerals (P, Ca, Mg, Na, K, and Cu) and on performance. Four blocks, each with 8 pens of 7 pigs, were formed. Eight dietary treatments were applied to each block in the 43-d experiment: supplementation of 0 (basal diet), 100, 250, 500, 750, 1,500, or 15,000 phytase units (FTU) or of 1.5 g of digestible P (dP; monocalcium phosphate; positive control) per kilogram of feed. The basal diet, with corn, barley, soybean meal, and sunflower seed meal as the main components, contained 1.2 g of dP per kilogram of feed. Fresh fecal grab samples were collected in wk 4 and 5 of the experiment. Average daily feed intake, ADG, G:F, and digestibility of all of the minerals increased (P < 0.001) with increasing phytase dose. Digestibility of P increased from 34% in the basal diet to a maximum of 84% in the diet supplemented with 15,000 FTU, generating 1.76 g of dP per kilogram of feed. At this level, 85% of the phytate phosphorus was digested, compared with 15% in the basal diet. Compared with the basal diet, digestibility of the monovalent minerals increased maximally at 15,000 FTU, from 81 to 92% (Na) and from 76 to 86% (K). In conclusion, phytase supplementation up to a level of 15,000 FTU/kg of a dP-deficient diet improved performance of weaner pigs and digestibility of minerals, including monovalent minerals. Up to 85% of the phytate-P was digested. Thus, dietary phytase supplementation beyond present day standards (500 FTU/kg) could further improve mineral use and consequently reduce mineral output to the environment.

Effect of phytase supplementation to a low- and a high-phytate diet for growing pigs on the digestibilities of crude protein, amino acids, and energy.

Supplementation of microbial phytase usually improves the digestibility and utilization of phosphorus in feedstuffs of plant origin. The effect of phytase supplementation on the digestibilities of AA also has been examined, but the results have been inconsistent. This study was carried out to determine the effect of phytase (Natuphos) supplementation, at a rate of 2,000 phytase units/kg, to two basal diets on the apparent ileal digestibilities (AID) of GE, CP, and AA, and on the apparent total-tract digestibilities (ATTD) of CP and GE. The basal diets contained 18% CP and were formulated (as-fed basis) to contain either a low (0.22%) or high content (0.48%) of phytate P. The high-phytate diet contained 20% rice bran, which is a rich source of phytate and has low intrinsic phytase activity. Eight barrows (average initial BW = 40.6 kg), fitted with a simple T-cannula at the distal ileum, were fed the four diets according to a replicated 4 x 4 Latin square design. The pigs were fed twice daily at 0800 and 2000, equal amounts each meal, at a rate of 2.4 times the daily maintenance requirement for ME. Each experimental period comprised 14 d. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Feces were collected from 0800 on d 8 until 0800 on d 12. Chromic oxide was used as the digestibility marker. The AID of GE, CP, and AA and the ATTD of CP and GE were less in the high- than in the low-phytate diet (P < 0.01). With the exception of glutamic acid, phytase supplementation did not affect (P > 0.10) the AID of CP and AA. There was no effect (P > 0.05) of phytase on the ATTD of CP and GE. These results show that if a response occurs to phytase supplementation, it is independent of the dietary phytate content.

Effect of phytase supplementation to diets for weanling pigs on the digestibilities of crude protein, amino acids, and energy.

Four experiments were conducted with weanling pigs fitted with a simple T-cannula at the distal ileum, to determine the effect of phytase supplementation to four diets on the apparent ileal digestibilities (AID) of CP and AA, and the apparent total-tract digestibilities (ATTD) of CP and DE. Phytase (Natuphos, DSM Food Specialties, Delft, The Netherlands) was supplemented at rates of 0, 500 or 1,000 FTU/kg to the four diets. A 20% CP (as-fed basis) corn-soybean meal diet was used in Exp. 1; a 20% CP wheat-soybean meal diet in Exp. 2; a 20% CP wheat-soybean meal-canola meal diet in Exp. 3; and a 19% CP barley-peas-canola meal diet in Exp. 4. In each experiment, six barrows, fitted with a simple T-cannula at the distal ileum, were fed the basal plus phytase-supplemented diets according to a repeated 3 x 3 Latin square design. Each experimental period comprised 14 d. The piglets were at fed 0800 and 2000 daily, equal amounts for each meal, at a daily rate of at least 2.4 times the maintenance requirement for ME. Feces were collected from 0800 on d 8 until 0800 on d 12 of each experimental period. Ileal digesta were collected from 0800 to 2000 on d 12, 13, and 14. Chromic oxide was used as the digestibility marker. The average initial and final BW (average of all experiments) were 7.9 and 16.5 kg, respectively. Phytase supplementation did not improve the AID of CP and AA in Exp. 1, 2, and 4; however, there were improvements (P < 0.05) or tendencies (P < 0.10) toward improvements in the AID of CP and AA or the ATTD of CP and the content of DE with phytase supplementation in Exp. 3. These results suggest that the AA response factor to microbial phytase supplementation depends on diet composition.

Determination of ultra-low concentrations of Pb-210 in Antarctic glacier with cation exchange resins filter--results, problems and perspectives.

In this paper, we describe a new, reliable and simple method to determine 210Pb concentration in ice-core samples, based on "Radium 3M" filters (USA). The advantages are well-known chemical yield, simplified retention procedure and measurement by low-energy Ge gamma spectrometry. We compare the results with those obtained by MN 616 LSA-50 filters (Germany). The method permits us to determine activity concentrations down to 30 mBq/l. We proved the efficiency and applicability of the method in the study of ice cores drilled in Livingston Island's glacier in Antarctica.

Microbial phytase improves performance, apparent metabolizable energy, and ileal amino acid digestibility of broilers fed a lysine-deficient diet.

An experiment was conducted to examine the effects of adding microbial phytase (Natuphos) on the performance in broilers fed a phosphorus-adequate, lysine-deficient diet. A wheat-soybean meal-sorghum-based diet, containing 1.00% lysine and 0.45% nonphytate phosphorus, was supplemented with L-lysine monochloride to provide 1.06, 1.12, or 1.18% lysine or with 125, 250, 375, 500, 750, or 1,000 phytase units (FTU)/kg diet. Each diet was fed to six pens of 10 chicks each from Day 7 to 28 posthatching. Addition of lysine to the lysine-deficient diet linearly increased (P < 0.001) weight gain and gain per feed of broilers. The response in weight gain to added phytase reached a plateau at 500 FTU/kg diet (quadratic effect, P < 0.001). Phytase had no effect on gain per feed to 250 FTU/kg diet and then increased (quadratic effect, P < 0.05) with further additions. Assuming that the observed responses in weight gain and gain per feed to added phytase were due to the release of lysine alone and by solving linear or nonlinear response equations of lysine and phytase levels, the lysine equivalency value was calculated to be 500 FTU phytase/kg diet = 0.074% lysine. Addition of increasing levels of supplemental phytase to the lysine-deficient diet improved (P < 0.001) the digestibilities of nitrogen and all amino acids. Phytase also increased the AME, and the response reached a plateau at 750 FTU/kg diet (quadratic effect, P < 0.001). These results showed that amino acid and energy responses are responsible for the performance improvements observed when phytase was added to a wheat-soybean meal-sorghum-based diet.

Intercomparison of passive radon-detectors under field conditions in epidemiological studies.

The Ardennes and Eifel region is a geologically distinct area covering parts of Germany, Belgium, France, and Luxembourg where enhanced concentrations of radon occur in some houses and other buildings. An international case-control study is being conducted to examine the role of radon in the etiology of lung cancer in this area. The radon detectors used are issued by different laboratories involving a variety of detector types and processes. A series of intercomparisons in houses was therefore conducted under similar conditions of exposure in the field. In most situations the different detectors gave similar results. Nevertheless, in some situations open and closed detectors yielded different results. Therefore, estimates of radon exposure have to be adjusted if results are to be pooled.

The efficacy of phytase in corn-soybean meal-based diets for laying hens.

Microbial phytase hydrolyzes poorly degradable vegetable phytate P in the gastrointestinal tract of poultry; thereby increasing the availability of organic P to an extent that remains to be established. For this purpose, the P equivalency value of phytase in corn-soybean meal layer diets was assessed in three experiments (two short-term absorption studies and one performance trial lasting a complete production period). In the first absorption study, two basal diets containing 30 or 40 g Ca/kg diet were supplemented with either phytase [0, 250, or 500 phytase units (FTU)/kg diet] or with monocalcium phosphate (MCP; 0, 0.5, or 1.0 g P/kg diet) and fed to layers from 20 to 24 wk of age. The ileal absorption of Ca and P was measured during the last week. It was shown that 250 FTU/kg diet hydrolyzed an amount of phytate P that was equivalent to 1.3 g P from MCP. At the highest phytase inclusion level (500 FTU/ kg diet), a lower value of equivalency was observed, as P absorption was almost maximal at the lower level of phytase inclusion (250 FTU/kg diet). Phytase hydrolyzed phytate-bound P effectively at both Ca levels, although this degradation was significantly reduced by 12 percentage units at the higher dietary Ca level. The second absorption study, used 0, 250, and 500 FTU phytase/kg diet and 0 and 1.0 g P/kg diet of MCP. All diets were standardized at 35 g Ca/kg diet. The ileal absorption of Ca and P was determined at 24 and 36 wk of age. These values were significantly reduced in 36-wk-old hens compared to 24-wk-old hens. At 24 wk of age, phytic acid P degradation was significantly improved with increasing levels of phytase up to the maximum inclusion level of 500 FTU/kg diet (maximum phytic acid-P degradation at the end of the small intestine was 66%). In this experiment, the dose of 250 FTU/kg diet was equivalent to 0.8 g MCP-P. In Experiment 3, either phytase or MCP-P was added to a corn-soybean meal layer diet, containing 40 g Ca/kg diet and 3.6 g P/kg diet, at levels of 0, 100, 200, and 300 FTU/kg or levels of 0, 0.3, 0.6, and 0.9 g MCP-P/kg, respectively. Production performance was measured from 18 to 68 wk of age. Diets were consumed ad libitum. Growth, production performances (except kilograms of feed per kilogram of egg), and tibia parameters were significantly improved by dietary supplementation of the negative control diet with either phytase or MCP-P. Growth, egg production, and feed conversion ratio of the hens from the supplemented groups remained good throughout the experiment. No phytase dose effects on the production characteristics or tibia parameters were observed, indicating that the P requirements of the laying hens were met throughout the production period even at the lowest level of supplementation.

Effects on chick performance and nutrient digestibility of an endo-xylanase added to a wheat- and rye-based diet in relation to fat source.

1. A study with growing chicks investigated the effects of an inclusion of an endo-xylanase preparation (LYXASAN) to a wheat- and rye-based diet on performance and nutrient digestibility in relation to the fat source. 2. The basal diet contained 500 g wheat and 100 g rye/kg of diet. The basal diet was supplemented with either 65 g soya oil/kg or 60 g blended animal fat and 5 g soya oil/kg. 3. Endo-xylanase added to the soya oil diet did not affect weight gain, but there was a numerical improvement in food conversion efficiency which was not statistically significant. When the endo-xylanase preparation was added to the blended animal fat diet, both weight gain and food utilisation were improved by 9.5% and 6.0%, respectively (P < 0.05). 4. Digestibilities of organic matter, crude fat, crude fibre and NFE were not significantly affected by adding endo-xylanase to the soya oil diet. However, when endo-xylanase was included in the blended animal fat diet, digestibility of organic matter, crude fat, crude fibre and NFE were improved (P < 0.05). The improvement in fat digestibility was the most pronounced, amounting to 9.4%. Nitrogen retention and metabolisable energy content were improved significantly by the addition of an endo-xylanase to the animal fat diet (P < 0.05), by 6.6% and 6.5% respectively. 5. From the results of this study, it can be concluded that the effects on chick performance and nutrient digestibility of a dietary endo-xylanase in a wheat- and rye-based diet are influenced to a considerable degree by the type of fat in the diet.