Increase In Nitrogen Excretion Research Articles

402 The effect of supplemental protein degradability and frequency of supplementation on nitrogen metabolism of beef cattle consuming low-quality forage

Abstract Rumen degradable protein (RDP) is required for cattle consuming low-quality forage to ensure adequate fiber digestion. However, in situations where cattle are not supplemented daily, supplementing RDP could overwhelm the nitrogen recycling mechanisms, leading to increased nitrogen excretion. The objective of this experiment was to determine the effect of rumen degradability and frequency of supplemental protein in beef cattle consuming low-quality forage. Treatments were arranged in a 2 × 2 factorial with protein degradability (68.5% or 32.8% RDP) and supplementation frequency (daily or biweekly) as the two factors. Ruminally cannulated Angus steers [n = 8; body weight (BW) = 328 ± 12.2 kg] were used in a Latin rectangle. The low RDP treatment was composed of 50% soybean hulls and 50% corn gluten meal (40.3% CP; 32.8% RDP), and the high RDP treatment consisted of 45.4% soybean hulls, 41.4% soybean meal, 4.1% urea, and 9.1% molasses (40% CP; 68.5% RDP). The biweekly steers were supplemented on d 0, 4, 7, 11, 14, 18, and 21 of each period. Steers were given ad libitum access to low-quality (7.4% CP) native grass hay. Daily blood samples were collected from d 14 to 17 at 0630 h and d 21 at -2, 3, and 7 h relative to supplementation. Rumen fluid samples were collected every 4 h on d 18 to 21. Daily NEFA concentrations decreased (P < 0.001) post-supplementation in the biweekly supplemented steers and then returned to baseline values, while the daily supplemented steers had no change. Hourly NEFA concentrations in steers supplemented with high RDP biweekly increased from 2 h pre-supplementation to 3 h post-supplementation (P < 0.001), then decreased at 7 h post-supplementation back to pre-supplementation concentrations. Plasma urea nitrogen (PUN) increased in biweekly high RDP supplemented steers 1 d after supplementation (P < 0.001) and decreased from d 15 to d 17. PUN concentrations increased from 2 h pre-supplementation through 7 h post-supplementation in both high RDP treatments, while low RDP treatments did not change (P < 0.001). Rumen fluid lactate and ammonia concentrations rapidly increased in the biweekly high RDP-supplemented steers in response to each supplementation (P < 0.001). There were spikes in ammonia concentrations for the daily high RDP treatment post-supplementation; however, they were smaller in magnitude compared with the biweekly high RDP. The low RDP treatments remained steady across all hours of ammonia sampling, where daily and biweekly supplemented steers decreased slightly in the time points following supplementation and then gradually increased. Rumen pH displayed drastic changes in the biweekly high RDP-supplemented group with values ranging from 6.99 to 5.97 (P < 0.001), but the low RDP treatments remained consistent. Supplementing biweekly with high RDP resulted in fluctuations in metabolites not observed in the other treatments, which could reduce forage utilization and increase nitrogen excretion.

Urinary metabolic characterization of advanced tuberculous meningitis cases in a South African paediatric population.

Tuberculous meningitis (TBM) is a severe form of tuberculosis with high neuro-morbidity and mortality, especially among the paediatric population (aged ≤12years). Little is known of the associated metabolic changes. This study aimed to identify characteristic metabolic markers that differentiate severe cases of paediatric TBM from controls, through non-invasive urine collection. Urine samples selected for this study were from two paediatric groups. Group 1: controls (n = 44): children without meningitis, no neurological symptoms and from the same geographical region as group 2. Group 2: TBM cases (n = 13): collected from paediatric patients that were admitted to Tygerberg Hospital in South Africa on the suspicion of TBM, mostly severely ill; with a later confirmation of TBM. Untargeted 1H NMR-based metabolomics data of urine were generated, followed by statistical analyses via MetaboAnalyst (v5.0), and the identification of important metabolites. Twenty nine urinary metabolites were identified as characteristic of advanced TBM and categorized in terms of six dysregulated metabolic pathways: 1) upregulated tryptophan catabolism linked to an altered vitamin B metabolism; 2) perturbation of amino acid metabolism; 3) increased energy production-metabolic burst; 4) disrupted gut microbiota metabolism; 5) ketoacidosis; 6) increased nitrogen excretion. We also provide original biological insights into this biosignature of urinary metabolites that can be used to characterize paediatric TBM patients in a South African cohort.

40 Effect of Soybean Meal Inclusion on Grow-Finish Pig Performance and Nitrogen Balance

Abstract Mixed-sex pigs (n = 240 PIC 337×1050; initial BW = 23 ± 4.7 kg) were used to evaluate the effects of soybean meal (SBM) inclusion on the growth performance and nitrogen balance of grow-finish pigs. Pigs were assigned across 60 split-sex pens, and pens were randomly assigned to one of three dietary treatments (10 pens∙treatments-1∙sex-1). Diets were formulated with increasing SBM for an approximate 3% incremental difference in crude protein (CP) between treatments. The treatments were: 1) low SBM (L-SBM) corn-soy diet supplemented with synthetic amino acids, 2) medium SBM diet (M-SBM) with SBM formulated to replace all synthetic lysine and equal to L-SBM in SID lysine, and 3) high SBM diet (H-SBM) contained excess levels of all amino acids. Diets were fed in four feeding phases ranging from approximately 25-50, 51-75, 76-105, and 106-135 kg for phases 1-4, respectively. From phases 1 to 4, SBM inclusion ranged from approximately 26-48% (SID Lys 1.06-1.32%), 19-41% (SID Lys 0.89-1.15%), 15-35% (SID Lys 0.76-1.01%), and 13-29% (SID Lys 0.68-0.86%), respectively. Additionally, diets within each phase were isocaloric. Pig BW and feed intake were measured for each phase to calculate ADG, ADFI, and G:F. On day 66, 18 gilts (n =6/treatment) were placed into metabolism stalls for total urine and feces collection over a 72 h period to assess CP digestibility and nitrogen balance. Pigs were marketed at approximately 134 kg BW, and carcass weight, backfat depth, and loin depth were measured at the harvest facility. Data were subject to ANOVA in SAS 9.4. Pen was the experimental unit, and the results were significant at P ≤ 0.05. Overall (d 0-98) pig ADFI, ADG, or G:F did not differ across treatments (P ≥ 0.202). However, there was a significant diet-by-phase interaction for ADG (P = 0.045) and G:F (P = 0.008), where H-SBM fed pigs grew faster in phase two compared with the M-SBM (1.07 vs. 1.02 kg/d; P = 0.026) or L-SBM (1.07 vs. 1.02 kg/d; P = 0.028) fed pigs. Consequently, in phase two, H-SBM pigs had improved G:F compared with M-SBM (0.47 vs. 0.44; P = 0.005) or L-SBM pigs (0.47 vs. 0.44; P = 0.001). However, these effects were not evident in the other phases. Apparent total tract digestibility of CP and nitrogen retention were similar between treatments (P ≥ 0.762). However, as expected, nitrogen retention as a proportion of intake, linearly decreased (P < 0.001) as SBM inclusion increased, which translated to an approximate 130% increase in total nitrogen excretion in pigs fed H-SBM compared with L-SBM (40.8 vs. 17.7 g/d; P < 0.001). In conclusion, low and high SBM formulations did not alter grow-finish pig overall performance. However, linearly increased nitrogen excretion was reported as SBM levels increased.

54 Impact of Ileal Indigestible Protein on Nitrogen Excretion and Fecal Microbiota may be Greater Compared with Total Protein Concentration of Diets in Growing Pigs

Abstract The effect of changes in dietary ileal indigestible protein concentration may be more influential in the amount of nitrogen flowing to the large intestine compared with changes in total dietary protein concentration. For this reason, we hypothesized that an increase in dietary ileal indigestible protein concentration induces an increase in hindgut nitrogen utilization and nitrogen excretion and a shift in fecal microbiota in growing pigs, when compared with pigs given a high total protein diet. Three diets were prepared: 1) standard protein diet based on corn and soybean meal, 2) high-indigestible protein diet in which autoclaved soybean meal replaced normal soybean meal in the first diet, and 3) high protein diet where the inclusion rate of soybean meal was greater than that of the other diets. T-cannulated barrows (n = 18; initial BW = 63.4 ± 8.0 kg) were allotted to the 3 diets in a randomized complete block design with BW as a blocking factor. Pigs were individually housed in pens and the experiment lasted for 23 days. On d 7 and 21, fecal samples were collected by rectal massage for microbiota analysis. Grab samples of feces were collected on d 20 and 21, and ileal digesta were collected on d 22 and 23 for the determination of energy and nitrogen utilization. Energy and nitrogen utilization data were analyzed using the MIXED procedure of SAS using a pig as the experimental unit and a model that included diet as a fixed variable and block as a random variable. For microbiome analysis, R was used. Alpha and beta diversity metrics were analyzed and the difference in abundance of the genus was determined using the DESeq2 function. The high-indigestible protein diet achieved decreased apparent ileal digestibility of nitrogen and resulted in greater ileal indigestible nitrogen concentration (P < 0.05). Apparent total tract digestibility of nitrogen was less (P < 0.05), and correspondingly fecal nitrogen concentration and daily fecal nitrogen output were greater (P < 0.05) in the high-indigestible protein diet. Apparent post-ileal digestibility and hindgut disappearance of nitrogen and gross energy were the greatest (P < 0.05) in the high protein diet. Beta diversity metrics of feces in the high-indigestible protein diet on d 21 were different (q < 0.05) from those in the other two diets, which indicates a shift in fecal microbiota. According to the DESeq2 results, the direction of the microbiota shift induced by the high-indigestible protein diet may have reduced hindgut fiber utilization. In conclusion, an increase in dietary ileal indigestible protein increased nitrogen excretion and shifted fecal microbial communities but did not increase hindgut nitrogen utilization.

Effect of Incorporating Cowpea (<i>Vigna unguiculata</i>) Meal into Broiler Diets on Environmental Pollution by Nitrogen from Poultry Excreta: A Review

Poultry feeds are formulated using soybean meal and animal by-products as sources of protein. Animal proteins like fish meal, blood meal, meat and bone meal are being shunned in formulating poultry feeds nowadays because they are associated with zoonotic diseases like salmonellosis and this has left soybean meal as the only source of dietary protein in broiler feeds. Soybean meal is in short supply in Zimbabwe and this country is relying on some soybean meal imports from South Africa and Zambia resulting in prices of poultry feed and broiler meat going upwards. Cheap and locally available alternative sources of protein to soybean meal must be found in order to reduce the cost of making poultry feed. The selected alternative source of protein must have protein which is highly digestible such that the bulk of this protein can be metabolized and utilized by broilers to synthesize meat leaving a little of it to be excreted through faeces and urine. Highly digestible protein is very important in broiler feed making because this reduces the amount of nitrogen lost through poultry excreta into the environment. Cowpea has been chosen to entirely or partially replace soybean meal in this review paper because it is locally grown, drought tolerant, cheap and its true protein digestibility (TPD) of 71% to 76% is generally comparable to 81% to 83% of soybean meal. Nowadays, people are concerned about protecting the environment from being polluted by wastes from industrial and agricultural activities. Poultry farming pollutes the environment with ammonia emitted from poultry excreta. The grain legumes used in formulating broiler feed such as soybean meal contain anti-nutritional factors which reduce protein digestibility and increase nitrogen excretion through poultry faeces. The nitrogen in faeces is volatilized into ammonia, emitted into the atmosphere and cause eutrophication of surface waters. Therefore, the effect of incorporating cowpea meal in broiler diets on environmental pollution by nitrogen excretion from broiler faeces needs to be explored.

315 Recognizing and Balancing Sustainable Trade-Offs in the Swine Industry

Abstract Recognizing and balancing trade-offs that constitute sustainability, economics, and practical reality is essential for practice adoption. There are many situations where producers have aligned all three criteria. Advancement of in-barn practices such as water cups compared to nipple drinkers provides for improved water conservation and economics. Also, injection of manure slurry directly into the soil decreases atmospheric nitrogen losses, reduces phosphorus runoff, reduces or eliminates inorganic fertilizer applications, and improves soil health and fertility. The use of dietary synthetic amino acids to lower nitrogen excretion or feed additives such as phytase to lower phosphorus excretion are widely used and are economical sustainable practices. Increasing whole farm productivity through improved pig survivability is a means to achieve a win-win tradeoff. Improving pig survivability with advancements in-barn management practices, genetic selection, health and nutritional programs will directly impact the sustainability of pork producers. However, everyday examples are also present where these criteria conflict. The use of feed by-products in diets to reduce feed cost per pig are common. However, these types of dietary ingredients, in particular dried distiller grains with solubles (DDGS) is lower in protein digestibility then soybean meal and corn, thus increases nitrogen excretion. At a higher inclusion such as 30% of the diet, the nitrogen excretion level would be raised by approximately 15%. Also, as the value of corn oil has increased for other industries, ethanol plants are extracting more oil from DDGS, in turn the net energy concentration is lowered. This results in pigs having poorer feed efficiency, thus increasing total manure production. Thus, the economic feed cost advantage has a tradeoff with increased nitrogen excretion and manure production. Pork producers will continue to be progressive and create opportunities to further combine sustainability, economics, and practical reality of implementation.

Aspects regarding renal morphophysiology of fruit-eating and vampire bats

Bats have adapted to many different feeding habits, which are known to induce morphophysiological adaptations in several tissues, especially those particularly involved with absorption, metabolism and excretion. The common vampire bat (Desmodus rotundus) has a very unique diet (blood), which, among other challenges, seems to pose a risk to their kidneys, due to the increased nitrogen excretion imposed by their remarkably high protein meal. Fruit-eating bats (Artibeus lituratus) consume a high carbohydrate diet and may be taken as a suitable species for this dietary comparative study. Here we aimed at investigating the renal morphology and stereology, kidneys antioxidant capacity, and plasma antidiuretic hormone (ADH) concentrations in adult fruit-eating and vampire bats. Sixteen animals were captured and used in this study, being 8 adult males from each species. Our results showed higher morphological standards of glomerular area, volumetric density of glomeruli, and renal somatic index for vampire bats, as well as higher reactive species of oxygen (ROS) production, such as nitric oxide (NO), higher plasma iron reduction ability (FRAP), higher activity of the antioxidant enzyme glutathione-S-transferase (GST) and a higher malondialdehyde production (MDA) in vampires’ kidneys, compared to the fruit-eating species. The activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) were higher in fruit-eating bats. Plasma ADH concentrations were not different between species. Taken together, the renal morphophysiology conditions presented by vampire bats might be associated with a high demand for nitrogenous products excretion imposed by protein and iron overload. These features may play an important role on preventing protein-overload nephropathy, allowing vampires to survive under such a unique diet.

Nutrients Mediate Bioavailability and Turnover of Proteins in Mammals.

As a major component of biologically active compounds in the body, proteins contribute to the synthesis of body tissues for the renewal and growth of the body. The high level of dietary protein and the imbalance of amino acid (AA) composition in mammals result in metabolic disorders, inefficient utilization of protein resources and increased nitrogen excretion. Fortunately, nutritional interventions can be an effective way of attenuating the nitrogen excretion and increasing protein utilization, which include, but are not limited to, formulating the AA balance and protein-restricted diet supplementing with essential AAs, and adding probiotics in the diet. This review highlights recent advances in the turnover of dietary proteins and mammal's metabolism for health, in order to improve protein bioavailability through nutritional approach.

Regulatory Role of Amino Acids in Pigs Fed on Protein-restricted Diets.

The high inclusion of dietary protein and the imbalance of amino acid (AA) composition in animal husbandry result in inefficient utilization of protein resources and increased nitrogen excretion. Therefore, an efficient approach to alleviate the nitrogen excretion and increase the utilization of protein resources is to formulate the AA-balance protein-restricted diet with crystalline AA supplementation. Nowadays, it is essential to thoroughly understand the regulatory mechanisms of AAs on body metabolism and their vital roles in protein-restricted diets. Besides, an establishment of the amino acid balanced protein-restricted diet system is beneficial for the maintenance of healthy environment and sustainable animal husbandry. This review focused on the recent advances on functional roles of AAs and development of a protein-restricted diet system in animal husbandry.

Association of protein intake with the outcomes of critically ill patients: a post hoc analysis of the PermiT trial

The optimal amount of protein intake in critically ill patients is uncertain. In this post hoc analysis of the PermiT (Permissive Underfeeding vs. Target Enteral Feeding in Adult Critically Ill Patients) trial, we tested the hypothesis that higher total protein intake was associated with lower 90-d mortality and improved protein biomarkers in critically ill patients. In this post hoc analysis of the PermiT trial, we included patients who received enteral feeding for ≥3 consecutive days. Using the median protein intake of the cohort as a cutoff, patients were categorized into 2 groups: a higher-protein group (>0.80 g · kg-1 · d-1) and a lower-protein group (≤0.80 g · kg-1 · d-1). We developed a propensity score for receiving higher protein. Primary outcome was 90-d mortality. We also compared serial values of prealbumin, transferrin, 24-h urinary nitrogen, and 24-h nitrogen balance on days 1, 7, and 14. Among the 729 patients included in this analysis, the average protein intake was 0.8±0.3 g · kg-1 · d-1 [1.0±0.2 g · kg-1 · d-1 in the higher-protein group (n=365) and 0.6±0.2 g · kg-1 · d-1 in the lower-protein group (n=364); P<0.0001]. There was no difference in 90-d mortality between the 2 groups [88/364 (24.2%) compared with 94/363 (25.9%), propensity score-adjusted OR: 0.80; 95% CI: 0.56, 1.16; P=0.24]. Higher protein intake was associated with an increase in 24-h urea nitrogen excretion compared with lower protein intake, but without a significant change in prealbumin, transferrin, or 24-h nitrogen balance. In the PermiT trial, a moderate difference in protein intake was not associated with lower mortality. Higher protein intake was associated with increased nitrogen excretion in the urine without a corresponding change in prealbumin, transferrin, or nitrogen balance. Protein intake needs to be tested in adequately powered randomized controlled trials targeting larger differences in protein intake in high-risk populations.

Internist, anesthesiologist and surgeon use of ketogenic diet.

Ketogenic diet is being increasingly utilized in recent decades because of its success as an effective tool for short and intermediate-term weight loss. Promoting physiological ketosis from a drastically low carbohydrate diet is the fundamental basis for this diet regime. Though debated, these diets have been demonstrated to be effective, at least in the short- to medium terms, to manage excess weight, hyperlipidemia, and other cardiovascular risk factors. We reviewed the cardiovascular, metabolic, anesthetic, and postsurgical profiles in the literature and summarized technical issues of anesthesia and surgery along with long-term changes from published papers. Doubts with ketogenic diet were raised due to possible renal damage caused by significant excretion of nitrogen found in animal models, the effects of acidosis, and the concerns of increasing triglycerides and cholesterol levels. Though current literature supports the efficacy of very low carbohydrate keto-diets their potential negative effects on renal function and acidosis are debated. An increase in nitrogen excretion during protein metabolism in the postoperative period could lead to renal damage. Research on the value of ketogenic diets is emerging because of its value in weight loss and in managing other pathologies.

Effects of replacing fish meal with corn gluten meal on growth, feed utilization, nitrogen and phosphorus excretion and IGF-I gene expression of juvenilePseudobagrus ussuriensis

Seven isonitrogenous and isolipidic diets containing fish meal (FM) protein replaced by corn gluten meal (CGM) protein at 0% (the control, C0), 10% (C10), 20% (C20), 30% (C30), 40% (C40), 50% (C50) and 60% (C60) were fed to juvenile Pseudobagrus ussuriensis for 8-weeks to evaluate the effects of FM protein replaced by CGM protein on growth, feed utilization, nitrogen (N) and phosphorus (P) excretion and IGF-I gene expression of juvenile P. ussuriensis. The results showed that the replacement level up to 40% did not affect the weight gain, specific growth rate (SGR), feed intake and protein efficiency ratio, whereas these parameters were depressed by further replacement level. Apparent digestibility coefficients (ADC) of dry matter, crude protein significantly decreased, but ADC of phosphorus significantly increased with increasing dietary CGM levels (p < .05). Fish fed diets with FM protein replaced by CGM protein led to an increase in nitrogen excretion, but led to a reduction in phosphorus excretion. No significant differences were observed in alpha-amylase and lipase activities of intestine (p > .05). The lowest pepsin activity was found in C60 group. Fish fed diet C40, C50 and C60 had significantly lower serum lysozyme activity compared with fish fed diet C0 (p < .05). The lowest plasma alkaline phosphatase activity and the highest plasma alanine aminotransferase and aspartate aminotransferase activities were observed in C60 group. Fish fed diet C60 had significantly lower hepatic IGF-I gene expression compared with fish fed diet C10 (p < .05). Broken-line model analysis based on SGR against the CGM substitution level indicated that the appropriate replacement level was 37.7%.

Performance, hematology and immunology of Salminus brasiliensis fed diets containing swine liver hydrolysate

Diets for carnivorous fish ordinarily contain large proportion of fish meal (FM), a high-cost and restricted feedstuff. Animal by-product hydrolysates are high-quality feedstuffs and potential surrogates to FM in fish diets. This study evaluated the performance of juvenile dourado Salminus brasiliensis, a carnivorous Characin, fed with increasing levels of swine liver hydrolysate. Juvenile dourado (4.57±1.25g) were stocked into 20,300-L, indoor plastic tanks (15 fish per tank), closed-loop recirculating system in a totally randomized experimental design (n=4), and fed to apparent satiation for 61days with practical diets containing graded levels of swine liver hydrolysate – SLH (0, 70, 140, 210 and 280gkg−1). Fish fed the SLH14 diet had higher feed intake and weight gain. Fish fed the SLH28 diet had the lowest rates of feed efficiency ratio (FER), protein efficiency ratio (PER), energy retention ratio (EER) and protein retention ratio (PRR). Diets containing in excess of 140gSLHkg−1 probably caused reduction of protein synthesis by fish, possibly resulting from higher proportion of small peptides and free amino acids in the feedstuff, which possibly elicited higher amino acid catalysis and increased nitrogen excretion. The lowest values of blood lysozyme were recorded for fish fed diet SLH7; on the other hand the oxidative burst was not influenced by the diet. Higher nitrogen excretion was recorded for in fish fed diets containing the highest levels of hydrolysate. Ultrafiltration of swine liver hydrolysates may elicit increasing the proportion of the product in fish diets and further studies on the economic feasibility of swine liver hydrolysate may shed additional light regarding its use as surrogate protein sources.

Muscle Protein Turnover and the Molecular Regulation of Muscle Mass during Hypoxia.

: Effects of environmental hypoxia on fat-free mass are well studied. Negative energy balance, increased nitrogen excretion, and fat-free mass loss are commonly observed in lowlanders sojourning at high altitude. Reductions in fat-free mass can be minimized if energy consumption matches energy expenditure. However, in nonresearch settings, achieving energy balance during high-altitude sojourns is unlikely, and myofibrillar protein mass is usually lost, but the mechanisms accounting for the loss of muscle mass are not clear. At sea level, negative energy balance reduces basal and blunts postprandial muscle protein synthesis, with no relevant change in muscle protein breakdown. Downregulations in muscle protein synthesis and loss of fat-free mass during energy deficit at sea level are largely overcome by consuming at least twice the recommended dietary allowance for protein. Hypoxia may increase or not affect resting muscle protein synthesis, blunt postexercise muscle protein synthesis, and markedly increase proteolysis independent of energy status. Hypoxia-induced mTORC1 dysregulation and an upregulation in calpain- and ubiquitin proteasome-mediated proteolysis may drive catabolism in lowlanders sojourning at high altitude. However, the combined effects of energy deficit, exercise, and dietary protein manipulations on the regulation of muscle protein turnover have never been studied at high altitude. This article reviews the available literature related to the effects of high altitude on fat-free mass, highlighting contemporary studies that assessed the influence of altitude exposure (or hypoxia) on muscle protein turnover and intramuscular regulation of muscle mass. Knowledge gaps are addressed, and studies to identify effective and feasible countermeasures to hypoxia-induced muscle loss are discussed.

The effects of heat stress on protein metabolism in lactating Holstein cows

Heat stress (HS) decreases milk protein synthesis beyond what would be expected based on the concomitant reduction in feed intake. The aim of the present study was to evaluate the direct effects of HS on milk protein production. Four multiparous, lactating Holstein cows (101 ± 10 d in milk, 574 ± 36 kg of body weight, 38 ± 2 kg of milk/d) were individually housed in environmental chambers and randomly allocated to 1 of 2 groups in a crossover design. The study was divided into 2 periods with 2 identical experimental phases (control phase and trial phase) within each period. During phase 1 or control phase (9 d), all cows were housed in thermal neutral conditions (TN; 20°C, 55% humidity) and fed ad libitum. During phase 2 or treatment phase (9 d), group 1 was exposed to cyclical HS conditions (32 to 36°C, 40% humidity) and fed ad libitum, whereas group 2 remained in TN conditions but was pair-fed (PFTN) to their HS counterparts to eliminate the confounding effects of dissimilar feed intake. After a 30-d washout period in TN conditions, the study was repeated (period 2), inverting the environmental treatments of the groups relative to period 1: group 2 was exposed to HS and group 1 to PFTN conditions. Compared with PFTN conditions, HS decreased milk yield (17.0%), milk protein (4.1%), milk protein yield (19%), 4% fat-corrected milk (23%), and fat yield (19%). Apparent digestibility of dry matter, organic matter, neutral detergent fiber, acid detergent fiber, crude protein, and ether extract was increased (11.1-42.9%) in HS cows, as well as rumen liquor ammonia (before feeding 33.2%; after feeding 29.5%) and volatile fatty acid concentration (45.3%) before feeding. In addition, ruminal pH was reduced (9.5 and 6% before and after feeding, respectively) during HS. Heat stress decreased plasma free amino acids (AA; 17.1%) and tended to increase and increased blood, urine, and milk urea nitrogen (17.2, 243, and 24.5%, respectively). Further, HS cows had reduced plasma glucose (8%) and nonesterified fatty acid (39.8%) concentrations compared with PFTN controls. These data suggest that HS increases systemic AA utilization (e.g., decreased plasma AA and increased nitrogen excretion), a scenario that limits the AA supply to the mammary gland for milk protein synthesis. Furthermore, the increase in AA requirements during HS might represent the increased need for gluconeogenic precursors, as HS is thought to prioritize glucose utilization as a fuel at the expense of nonesterified fatty acids.

Alternative ingredients for providing adequate methionine in organic poultry diets in the United States with limited synthetic amino acid use

Synthetic methionine use is currently limited to 1 kg and 1.5 kg per metric tonne (2, 2, and 3 lbs per short ton) of feed for organic laying hens, broilers, and turkeys and other poultry, respectively, in the United States of America. All other synthetic amino acids (AA) have been banned from use in organic poultry diets in this country. It is challenging to provide sufficient methionine (Met) to maintain bird growth and productive performance up to current industry standards given the recent restrictions that have been placed on synthetic Met. Without synthetic AA, Met requirements can alternatively be obtained for organic poultry by dramatically increasing dietary crude protein (CP) e.g. via additional inclusion of expeller-pressed soybean meal to the diets. However, this strategy leads to both major increases in feed costs and environmental concerns due to increasing nitrogen excretion, with concurrent rises in ammonia emissions, and corresponding welfare issues due to ammonia and litter quality. This review aims to examine feed ingredients that may contribute to a solution to this issue. Otherwise, further negative impacts may soon be felt from the current limitation on synthetic Met or a potential ban on its entire use in the future.

No protein intake compensation for insufficient indispensable amino acid intake with a low-protein diet for 12days.

BackgroundProtein quality evaluation aims to determine the capacity of food sources and diets to meet protein and indispensable amino acid (IAA) requirements. This study determined whether nitrogen balance was affected and whether dietary IAA were adequately obtained from the ad libitum consumption of diets at three levels of protein from different primary sources for 12 days.MethodsTwo 12-day randomized crossover design trials were conducted in healthy subjects [n = 70/67 (M/F); age: 19-70 y; BMI: 18.2-38.7 kg/m2]. The relative dietary protein content was lower than [5% of energy (En%)], similar to (15En%), and higher than (30En%) customary diets. These diets had a limited variety of protein sources, containing wheat protein as a single protein source (5En%-protein diet) or 5En% from wheat protein with 10En% (15En%-protein diets) or 25En% (30En%-protein diets) added from whey with α-lactalbumin, soy or beef protein.ResultsThere was a dose-dependent increase in nitrogen excretion with increasing dietary protein content, irrespective of the protein sources (P = 0.001). Nitrogen balance was maintained on the 5En%-protein diet, and was positive on the 15En%- and 30En%-protein diets (P < 0.001) over 12 days. Protein intake from the 5En%-protein diet did not reach the amount necessary to meet the calculated minimal IAA requirements, but IAA were sufficiently obtained from the 15En%- and 30En%-protein diets. In the 15En%- and 30En%-protein conditions, a higher protein intake from the soy-containing diets than from the whey with α-lactalbumin or beef containing diets was needed to meet the minimal IAA requirements.ConclusionProtein intake did not compensate for an insufficient indispensable amino acid intake with a low-protein diet for 12 days.Trial registrationThese trials were registered at clinicaltrials.gov as NCT01320189 and NCT01646749.

Symptomatic hyperammonemia after lung transplantation: Lessons learnt

Hyperammonemia, post-orthotopic lung transplantation, is a rare but mostly fatal complication. Various therapies, including those to decrease ammonia generation, increase nitrogen excretion, and several dialytic methods for removing ammonia have been tried. We describe three lung transplant recipients who developed acute hyperammonemia early after transplantation. Two of the three patients survived after a multidisciplinary approach including discontinuation of drugs, which impair urea cycle, aggressive ammonia reduction with prolonged daily intermittent hemodialysis (HD), and overnight slow low-efficiency dialysis in conjunction with early weaning of steroids and other therapeutic measures. Our experience suggests that early initiation of dialysis, high dialysis dose, increased frequency, and HD preferably to less efficient modalities increases survival in these patients.

Amino acid reduction in broiler diets supplemented with phytase and elaborated according to different nutritional plans

The need for suitable diets in chickens, considering the ideal protein concept associated with phytase, is important in order to improve the productivity of birds. The aim of this study was to assess the need for the correction of amino acid levels in the diets of broilers, by using different combinations of crude protein (CP) supplemented with phytase. For performance, eight days old Cobb 875 broiler chicks, with initial body weights of 155 ± 1.4g were used. The birds were distributed in a completely randomised design with seven treatments (nutritional plans) and five replicates of 25 birds. For the metabolism trial, 300 birds were selected which were also distributed using the same design, but with five, four and three birds per experimental stage: 8-21 days, 22-35 days and 36- 42 days. The nutritional plans consisted of different combinations of CP in diets with reduced calcium and phosphorus, supplemented with phytase and amino acids. The reduction of amino acids in diets with reduced levels of CP resulted in an increased intake, feed conversion and abdominal fat level, and decreased the yield of thigh + drumstick. The inclusion of phytase reduced the excretion of calcium and phosphorus, but increased nitrogen excretion when the CP was not reduced. As a result, this study concluded that the reduction of amino acids to 3.5%, supplemented with phytase and prepared according to a nutritional plan does not improve the performance and carcass characteristics of broilers, although it may reduce the emission of polluting elements by excreta.

Corn texture and particle size in broiler diets

The objective of this study was to evaluate the effect of corn texture and the particle size on broiler performance, carcass yield, nutrient digestibility, and digestive organ morphometrics. In Experiment I, 720 male Cobb chicks were distributed in a completely randomized experimental design with a 2 x 3 factorial arrangement, consisting two corn textures (dented and hard) and three corn particle sizes, was applied, with four replicates of 30 birds each. Corn particle size was classified according to geometric mean diameter (GMD) as fine - 0.46 mm; medium - 0.73 mm, and coarse - 0.87 mm. In Experiment II, 120 broiler chicks were used to evaluate corn digestibility during the periods of 16 to 22 days and 35 to 41 days of age, using the method of total excreta collection. In Experiment I, corn particle size influenced body weight, average weight gain, feed intake and feed conversion ratio of 21-day-old birds. Corn texture and particle size did not affect the performance of 42-day-old broilers or carcass traits. In Experiment II, there was no influence of corn texture and particle size on digestive organ weights. Dented corn increased nitrogen excretion in the first trial, and hard corn improved dry matter digestibility in the second metabolic trial. Corn with fine particle size promotes better performance of broilers at 21 days of age. Hard corn results in higher dry matter digestibility and lower nitrogen excretion, and consequently higher production factor in 42-day-old broilers.