Chronic N loading reduces N retention across varying base flows in a desert river

2011 ◽  
Vol 30 (2) ◽  
pp. 559-572 ◽  
Author(s):  
Rebecca A. Martin ◽  
Tamara K. Harms ◽  
Nancy B. Grimm
Keyword(s):  
N Retention ◽  
N Loading ◽  
Base Flows

scholarly journals Influence of peracetic acid-ethanol sterilisation on the biomechanical properties of human meniscus transplants

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Volker Eras ◽  
Josefine Graffunder ◽  
Norus Ahmed ◽  
Jan C. Brune
Keyword(s):  
Peracetic Acid ◽  
Biomechanical Properties ◽  
Bone Block ◽  
Test Device ◽  
Level Of Evidence ◽  
Load To Failure ◽  
Graft Extrusion ◽  
Fresh Frozen ◽  
Failure Loads ◽  
N Loading

Abstract Purpose Meniscus allograft transplantation (MAT) is a possible treatment for patients suffering with pain after meniscectomy. Here, peracetic acid (PAA) sterilised meniscus transplants were investigated on whether they would provide an adequate alternative to fresh-frozen transplants in their viscoelastic and mechanical properties. Methods In this analysis, 31 menisci donors (26 male and 5 female) were included. The average donor age was 49.87 years, ranging from 32 to 65 years. Menisci of matched pairs of knees underwent chemical sterilisation while counterparts were left fresh-frozen. Stiffness and load to failure were determined via suture retention. Further menisci were analysed while attached to the tibial bone block using a novel test device to mimic physiological load distribution. Meniscus relaxation, stiffness and failure loads were determined. Histology and biphasic properties of the menisci were examined and results were analysed using paired t-tests. Results A novel custom built test device allowed the application of physiological loads for suture retention testing and revealed no significant differences between PAA sterilised (14.85 ± 4.46 N/mm, 50.49 ± 17.01 N) and fresh-frozen (18.26 ± 4.46 N/mm, 59.49 ± 21.07 N) regarding stiffness and failure load, respectively. Furthermore, initial 200 N loading showed significantly higher strain in sterilised menisci (18.87 ± 1.56) compared to fresh frozen (13.81 ± 1.04). Load relaxation experiments demonstrated significantly lower relaxation for sterilised menisci (77.71 ± 1.62) compared to fresh-frozen (89.11 ± 1.00, p-value < 0.0001). Conclusion Peracetic acid sterilised human menisci performed equally to fresh-frozen counterparts in a suture retention test and in physiological failure testing providing an adequate alternative. However, meniscus relaxation, biphasic properties and strain were shown to be significantly different between the groups. A common problem of MAT is graft extrusion or shrinkage, therefore the parameters measured here should be considered and may influence meniscus extrusion after transplantation. Level of evidence n/a (experimental study)

scholarly journals 14 Challenges and opportunities for formulating low-protein diets for maintaining growth and N-retention of weanling and growing-finishing pigs

2020 ◽  
Vol 98 (Supplement_3) ◽  
pp. 16-17
Author(s):  
John K Htoo
Keyword(s):  
Energy Content ◽  
Optimal Growth ◽  
Energy Utilization ◽  
Backfat Thickness ◽  
Finishing Pigs ◽  
N Retention ◽  
Insufficient Amount ◽  
Challenges And Opportunities ◽  
Pig Performance ◽  
Crystalline Amino Acids

Abstract For more than two decades, numerous studies have been conducted evaluating the effects of lowering CP level in pig diets. It is now accepted that lowering dietary CP level and adding crystalline amino acids (CAA) improves N utilization and consequently reduces N excretion. Increased availability of CAA such as Lys, Thr, Met, Trp, Val (Ile, Arg and His) allows nutritionists to further reduce dietary CP level while meeting pigs’ AA requirements more closely. However, pig performance was sometimes compromised when the dietary CP level was reduced more than 4 percentage units and adding high inclusion levels of CAA. An increase in backfat thickness was also sometimes reported when feeding finishing pigs with low CP diets. The potential reasons for such inconsistent results are due to the deficiency of the next limiting AA (typically Val and Ile), inaccurate feed mixing and insufficient amount of non-essential AA (NEAA) in the low CP diets. Formulating low CP diets on similar energy content as for the high CP diets on ME basis sometimes led to a greater backfat thickness in finishing pigs which was mainly due to increased energy utilization of pigs fed low CP diets coupled with the excess energy being stored as carcass fat. Based on the results of these experiments, optimal growth performance, carcass quality and N retention of pigs can be maintained when low CP diets are balanced for adequate levels of both essential AA and NEAA on the standardized ileal digestible basis combined with formulating on NE basis. Research suggests that keeping a maximum total Lys:CP ratio of 7.4% could overcome deficiency of NEAA in the low CP diets. Based on published N-balance studies, 1 percent unit dietary CP reduction results on average 9% reduction in N excretion in pigs which is an effective approach to become more sustainable pork production.

scholarly journals Nitrogen cycling in Sandusky Bay, Lake Erie: oscillations between strong and weak export and implications for harmful algal blooms

2018 ◽  
Vol 15 (9) ◽  
pp. 2891-2907 ◽  
Author(s):  
Kateri R. Salk ◽  
George S. Bullerjahn ◽  
Robert Michael L. McKay ◽  
Justin D. Chaffin ◽  
Nathaniel E. Ostrom
Keyword(s):  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Lake Erie ◽  
N Uptake ◽  
N Fixation ◽  
N Budget ◽  
N2o Production ◽  
N Removal ◽  
Uptake Rates ◽  
N Loading

Abstract. Recent global water quality crises point to an urgent need for greater understanding of cyanobacterial harmful algal blooms (cHABs) and their drivers. Nearshore areas of Lake Erie such as Sandusky Bay may become seasonally limited by nitrogen (N) and are characterized by distinct cHAB compositions (i.e., Planktothrix over Microcystis). This study investigated phytoplankton N uptake pathways, determined drivers of N depletion, and characterized the N budget in Sandusky Bay. Nitrate (NO3-) and ammonium (NH4+) uptake, N fixation, and N removal processes were quantified by stable isotopic approaches. Dissimilatory N reduction was a relatively modest N sink, with denitrification, anammox, and N2O production accounting for 84, 14, and 2 % of sediment N removal, respectively. Phytoplankton assimilation was the dominant N uptake mechanism, and NO3- uptake rates were higher than NH4+ uptake rates. Riverine N loading was sometimes insufficient to meet assimilatory and dissimilatory demands, but N fixation alleviated this deficit. N fixation made up 23.7–85.4 % of total phytoplankton N acquisition and indirectly supports Planktothrix blooms. However, N fixation rates were surprisingly uncorrelated with NO3- or NH4+ concentrations. Owing to temporal separation in sources and sinks of N to Lake Erie, Sandusky Bay oscillates between a conduit and a filter of downstream N loading to Lake Erie, delivering extensively recycled forms of N during periods of low export. Drowned river mouths such as Sandusky Bay are mediators of downstream N loading, but climate-change-induced increases in precipitation and N loading will likely intensify N export from these systems.

Nutritive value of Albizia lebbek supplements for growing sheep

1992 ◽  
Vol 32 (3) ◽  
pp. 273 ◽  
Author(s):  
i Dwatmadj ◽  
E Teleni ◽  
AR Bird ◽  
JB Lowry
Keyword(s):  
Plasma Glucose ◽  
Nutritive Value ◽  
Environmental Temperature ◽  
Daily Maximum ◽  
Albizia Lebbeck ◽  
N Retention ◽  
Grass Hay ◽  
Ad Libitum ◽  
Dietary Treatments ◽  
Albizia Lebbek

This study was undertaken to evaluate the effect of supplements of siris (Albizia lebbeck) flowers and leaves on Merino wethers fed Mitchell grass hay (Astrebla spp.). Three groups, each of 6 sheep, were fed the following diets: hammermilled Mitchell grass hay ad libitum (M); M + 181 g DM/day of siris flowers (MF), and M + 216 g DM/day of siris leaves (ML). The experiment, conducted over 17 days, measured feed intake and digestibility, nitrogen (N) retention, and plasma glucose and urea concentrations. The total DM intakes by MF and ML sheep were significantly (P<0.01) higher than those in M sheep. As a result of the supplement of siris flowers, the digestibility of the MF diet was highest (P<0.01). Sheep fed the M diet showed negative N retention, while MF and ML sheep showed positive N retention. The increased (P<0.01) N retention in the MF and ML sheep was associated with increased (P<0.01) urinary N excretion. The improved nutritional state of MF and ML sheep was associated with increases in plasma glucose and urea concentrations. Environmental temperature, which reached a mean daily maximum of 31.3�C, did not interact with the dietary treatments.

171 Effects of Dietary Valine, Isoleucine, and Tryptophan Supplementations to Diets Containing Excess Leucine on Nitrogen Balance of Growing Pigs

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 61-61
Author(s):  
Woongbi Bi Kwon ◽  
Jose A Soto ◽  
Hans H Stein
Keyword(s):  
Body Weight ◽  
Crude Protein ◽  
Random Effect ◽  
Basal Diet ◽  
Growing Pigs ◽  
Negative Effects ◽  
Initial Body Weight ◽  
N Retention ◽  
Biological Value ◽  
Main Effects

Abstract An experiment was conducted to test the hypothesis that increasing concentrations of dietary Val, Ile, or Trp alone or in combination will alleviate negative effects of excess dietary Leu on N balance of growing pigs. Seventy-two barrows (initial body weight: 33.9 ± 2.6 kg) were housed in metabolism crates and randomly assigned to 1 of 8 diets and 3 blocks with 3 pigs per diet in each block in a 12-d experiment. Treatments were arranged in a 2 × 2 × 2 factorial with the main effects of L-Val (0 or 0.1%), L-Ile (0 or 0.1%), and L-Trp (0 or 0.05%) that were added to a basal diet containing corn and a high-protein corn product (48% crude protein; 5.9% Leu). The basal diet contained 1.00 % standardized ileal digestible (SID) Lys and 171% SID Leu:Lys. Data were analyzed using the PROC MIXED of SAS with concentrations of Val, Ile, and Trp, and all interactions as main effects and replicate as a random effect. No 3-way interactions were observed (Table 1). Results indicated that fecal N output increased if Ile was added to diets without added Val, but that was not the case if Val was added (interaction, P &lt; 0.05). Addition of Ile to diets reduced N retention, but N retention increased with Trp addition to diets without Val addition, but not if Trp was added to diets with added Val (interaction, P &lt; 0.05). The biological value of protein increased if Trp was added to diets without addition of Ile, but if Ile was added, Trp addition did not increase the biological value of protein (interaction, P &lt; 0.05). In conclusion, adding Ile to a diet with excess Leu reduced N retention, but if Trp was added alone or in combination with Ile or Val, N retention increased.

scholarly journals Nitrogen Balance of Effluent Irrigated Silage Cropping Systems in Southern Australia

2001 ◽  
Vol 1 ◽  
pp. 35-41
Author(s):  
Chris J. Smith ◽  
Val O. Snow ◽  
Ray Leuning ◽  
David Hsu
Keyword(s):  
Soil Profile ◽  
Irrigation System ◽  
Cropping Systems ◽  
Irrigation Season ◽  
Alkaline Ph ◽  
High Recovery ◽  
Mineral N ◽  
Effluent Reuse ◽  
Spray Irrigation ◽  
N Loading

The nitrogen (N) balance in a double-cropped, effluent spray irrigation system was examined for several years in southern Australia. The amounts of N added by irrigation, removed in the crop, and lost by ammonia (NH3) volatilisation, denitrification, and leaching were measured. Results from the project provide pig producers with the knowledge necessary to evaluate the efficiency of such systems for managing N, and enable sustainable effluent reuse practices to be developed. Oats were grown through the winter (May to November) without irrigation, and irrigated maize was grown during the summer/autumn (December to April). Approximately 18 mm of effluent was applied every 3 days. The effluent was alkaline (pH 8.3) and the average ammoniacal-N (NH4++ NH3) concentration was 430 mg N/l (range: 320 to 679 mg N/l). Mineral N in the 0- to 1.7-m layer tended to increase during the irrigation season and decrease during the winter/spring. About 2000 kg N/ha was found in the profile to a depth of 2 m in October 2000. N removed in the aboveground biomass (oats + maize) was 590 and 570 kg N/ha/year, equivalent to ≈25% of the applied N. Average NH3volatilisation during the daytime (6:00 to 19:00) was 2.74 kg N/ha, while volatilisation at night (19:00 to 6:00) was 0.4 kg N/ha, giving a total of 3.1 kg N/ha/day. This represents ≈12% of the N loading, assuming that these rates apply throughout the season. The balance of the N accumulated in the soil profile during the irrigation season, as 15N-labelled N studies confirmed. The high recovery of the15N-labelled N, and the comparable distribution of 15N and Br in the soil profile, implied that there was little loss of N by denitrification, even though the soil was wet enough for leaching of both tracers.

Wood ash application in a managed Norway spruce plantation did not affect ectomycorrhizal diversity or N retention capacity

2019 ◽  
Vol 39 ◽  
pp. 1-11 ◽  
Author(s):  
Carla Cruz-Paredes ◽  
Tobias Guldberg Frøslev ◽  
Anders Michelsen ◽  
Toke Bang-Andreasen ◽  
Mette Hansen ◽  
...  
Keyword(s):  
Norway Spruce ◽  
Wood Ash ◽  
Retention Capacity ◽  
N Retention ◽  
Ectomycorrhizal Diversity

RESPONSE OF EARLY WEANED PIGS TO DIETS OF DIFFERENT DIGESTIBLE ENERGY CONCENTRATIONS AND THE EFFECTS OF CEREAL SOURCE AND ADDED MOLASSES ON PERFORMANCE

1972 ◽  
Vol 52 (1) ◽  
pp. 87-96 ◽  
Author(s):  
J. F. O’GRADY ◽  
J. P. BOWLAND
Keyword(s):  
Growth Rate ◽  
G Protein ◽  
Dietary Protein ◽  
Lower Energy ◽  
Energy Levels ◽  
Constant Ratio ◽  
Initial Weight ◽  
N Retention ◽  
Digestible Energy ◽  
Very High

One hundred and sixty pigs weaned at 2 weeks were allotted at an average initial weight of 3.8 kg to two experiments to examine the effects of diets based on barley or wheat as the cereal component and having digestible energy (DE) concentrations ranging from 2.8 to 3.6 Mcal/kg. Protein was in constant ratio to DE (15.2 kcal DE/g protein). Very high mortality was experienced on the lower energy levels, although the inclusion of 5% molasses in the formulation reduced mortality. Among surviving pigs, growth rate was significantly reduced at lower energy concentrations. The optimum DE level for maximum gain was 3.2 Mcal in the first experiment and 3.4 Mcal/kg in the second. The efficiency of utilization of DE for growth was best at a DE concentration of 3.2 Mcal/kg in the first experiment but did not vary in the second. Digestibility of dietary protein increased with increasing dietary DE but nitrogen (N) retention as percentage of N intake or of digestible N was not significantly influenced by DE in the diet.

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