scholarly journals Protein requirements in tropical countries: nitrogen losses in sweat and their relation to nitrogen balance

1967 ◽  
Vol 21 (4) ◽  
pp. 833-843 ◽  
Author(s):  
Ann Ashworth ◽  
A. D. B. Harrower
Keyword(s):  
Initial Period ◽  
Tropical Climate ◽  
The Body ◽  
N Balance ◽  
Nitrogen Losses ◽  
Whole Body ◽  
Physical Work ◽  
N Loss ◽  
Total N ◽  
Protein Requirements

1. An experiment was undertaken to determine whether high rates of sweating in a tropical climate affect protein requirements by increasing the total nitrogen losses from the body.2. Six fully acclimatized volunteers were given a diet supplying 50 g protein (= 8 g N) daily. They performed strenuous physical work of a normal nature for an average of 6½ h a day for two 5-day periods. During control periods the subjects took minimal exercise and lived in a cool environment. N balance was measured throughout.3. Rates of sweating were measured by weighing. Whole body sweat was collected and the concentrations were measured of nitrogen, sodium and potassium. During 6½ h work approximately 3 l. of sweat were lost, containing on average 0·49 g N, 64 m-equiv. Na and 22 m-equiv. K.4. The N concentration in sweat was 0·20 mg/g, which is lower than that found by most other workers. It is suggested that acclimatization is an important factor in reducing N loss by sweating.5. There was a marked decrease in urinary Na excretion during sweating, which compensated fully for the loss of Na in sweat. Renal compensation for loss of K was less efficient.6. Because the total N loss in sweat was small, it was not possible to establish with certainty whether it was compensated for by a reduced renal excretion of N. However, after the initial period the subjects were in N balance in spite of the relatively low protein intake.7. It is concluded that there is no evidence to suggest that heavy sweating under natural conditions in a tropical climate causes a significant increase in protein requirements.

scholarly journals Effects of substitution of tricaproin for tallow and of protein concentration in milk substitutes on nitrogen and energy balance in the preruminant lamb

1988 ◽  
Vol 60 (3) ◽  
pp. 525-538
Author(s):  
Bernard Aurousseau
Keyword(s):  
Milk Fat ◽  
Protein Concentration ◽  
Coconut Oil ◽  
Metabolizable Energy ◽  
High Protein ◽  
N Balance ◽  
Total N ◽  
Protein Requirements ◽  
High Protein Concentration ◽  
Milk Substitute

1. Results of 138 nitrogen balance studies from experiments with forty male Limousin and nineteen male Ile de France preruminant lambs were used to estimate total N requirements and to assess the effects of dietary tricaproin inclusion, protein concentration, lysine and methionine supplementation and the age of lambs on protein retention. In addition, energy balances were obtained in twenty-four of the Limousin lambs from birth up to 3 weeks of age by means of a slaughter technique.2. For milk substitute unsupplemented with amino acids, tricaproin inclusion increased N balance slightly (P < 0.001) when a medium-protein concentration (260 g/kg dry matter (DM)) was used, in 2-week-old lambs (+4.3%) and in 5-week-old Limousin lambs (+5.3%), or very markedly when a high-protein concentration (320 g/kg DM) was used, in 2-week-old lambs (+14.5%) and in 5-week-old lambs (+18.6%). Protein requirements decreased from 300 g/kg DM in 3-week-old lambs to 270 g/kg DM in 5-week-old lambs for the control milk containing tallow-coconut oil mixture (0.67:0.33 by wt) and was increased above 300 g/kg DM at all ages in the case of experimental milk containing tallow-coconut oil-tricaproin mixture (0.33:0.33:0.33, by wt).3. For milk containing either a medium- or a high-protein concentration and supplemented with lysine and methionine, inclusion of tricaproin increased N balance (P < 0.01) to a similar extent (+8.5 up to +14.3 %) in 1 to 2- and 3-week-old Limousin lambs. An increase in N concentration in the milk had no effect in 1 - and 2-week-old lambs, but led to a decreased N balance in 3-week-old lambs. Protein requirements decreased from 310 g/kg DM in 1-week-old lambs to 190 g/kg DM in 3-week-old lambs for the milk containing tallow-coconut oil or from 300 g/kg DM in 2-week-old lambs to 210 g/kg DM in 3-week-old lambs for the milk containing tallow-coconut oil-tricaproin.4. For the Ile de France lambs given milk supplemented with lysine and methionine, tricaproin inclusion did not alter N balance. Protein requirements decreased from 370 g/kg DM in 2-week-old lambs to 270 g/kg DM in 4-week-old lambs for milk containing both kinds of fat mixtures.5. Between birth and 3 weeks of age, efficiency of metabolizable energy (ME) utilization in the Limousin lambs was not dependent on the nature of the milk fat or the protein concentration of the diet (ME efficiency for tissue deposition varying from 0.672 to 0.698) whilst ME efficiency for protein deposition was 0.52 and ME efficiency for lipid deposition was close to 1; daily maintenance expenditure was 553 kJ/kg body-weight0.75

scholarly journals The effect of work level and dietary intake on sweat nitrogen losses in a hot climate

1972 ◽  
Vol 27 (3) ◽  
pp. 543-552 ◽  
Author(s):  
J. S. Weiner ◽  
J. O. C. Willson ◽  
Hamad El-Neil ◽  
Erica F. Wheeler
Keyword(s):  
Normal Diet ◽  
Physical Work ◽  
N Loss ◽  
N Losses ◽  
Total N ◽  
Adequate Diet ◽  
N Concentration ◽  
Hot Climate ◽  
Rate Of Increase ◽  
Work Level

1. Nitrogen intakes, and N output in urine, faeces and sweat have been measured in six young Tanzanian men who were accustomed to a hot climate. The measurements were done while the subjects were receiving first a normal and then a low-N diet; and when they were performing moderate physical work, and had undergone a period of acclimatization.2. When the subject were acclimatized and working on a normal diet, their sweat output increased, with a fall in its N concentration. Total sweat N loss increased from an average of 0.10 to 0.71 g/d.3. The effect of the low-N diet was to decrease both the sweat N concentration, and the rate of increase of total N loss in sweat, as sweat volume increased.4. It is estimated that maximum sweat N losses would not exceed 1 g/d on an adequate diet, or 0.5 g/d on a low-protein diet. Our results provide no basis for recommending extra protein allowances to cover sweat N losses for workers in tropical climates.

scholarly journals Gaseous Nitrogen Losses from Tropical Soils with Liquid or Granular Urea Fertilizer Application

2021 ◽  
Vol 13 (6) ◽  
pp. 3128
Author(s):  
Ahmmed Md Motasim ◽  
Abd Wahid Samsuri ◽  
Arina Shairah Abdul Sukor ◽  
Amin Mohd Adibah
Keyword(s):  
N2o Emission ◽  
Nitrogen Losses ◽  
Clay Loam ◽  
Soil Series ◽  
Nh3 Volatilization ◽  
N Loss ◽  
N Content ◽  
Total N ◽  
Sandy Clay Loam ◽  
Sandy Clay

Gaseous loss of N leads to lower nitrogen use efficiency (NUE) of applied urea and N content of the soil. This laboratory study was conducted to compare the nitrogen losses from two tropical soil series (Bungor sandy clay loam and Selangor clay) incubated with either liquid urea (LU) or granular urea (GU) at 0, 300, 400, or 500 mg/kg of soil for thirty days. The NH3 volatilization, N2O emission, and N content in the soils were measured throughout the incubation period. For the same application rate, the total NH3 volatilization loss was higher in GU-treated soils than the LU-treated soils. NH3 volatilization loss continued up to the 15th day in the Selangor soil, while in the Bungor soil series it continued up to the 26th day. Higher amounts of N2O emissions were recorded in GU-treated soils than the LU-treated soils, and N2O emission increased with increasing rate of GU and LU applications in both soils. The N2O emission was higher only in the first few days and then tapered off at the seventh and eighth day in Bungor and Selangor soil series, respectively. The total N2O emission was higher in the Selangor soil series than that of Bungor soil series. The total N content that remained in the LU-treated soils after 30 days of incubation was higher than the GU-treated soils. The total N loss from applied urea was higher in the sandy clay loam Bungor soils than that of clayey Selangor soil series. The results suggest that the LU may be a better N fertilizer source than GU due to lower N loss from NH3 volatilization and N2O emission.

scholarly journals Human protein requirements: obligatory urinary and faecal nitrogen losses and the factorial estimation of protein needs of Nigerian male adults

1985 ◽  
Vol 54 (3) ◽  
pp. 605-611 ◽  
Author(s):  
T. Atinmo ◽  
C. M. F. Mbofung ◽  
M. A. Hussain ◽  
B. O. Osotimehin
Keyword(s):  
Body Weight ◽  
University Students ◽  
Energy Intake ◽  
Protein Intake ◽  
Nitrogen Losses ◽  
N Loss ◽  
N Losses ◽  
Protein Requirements ◽  
The University ◽  
The Village

1. The present study was designed to use the factorial approach to estimate protein requirements of Nigerian male adults by measuring obligatory nitrogen losses via urine, faeces and sweat when N intake was very low and energy intake adequate.2. Eight adult men from Osegere village near Ibadan and seven medical students from the University of Ibadan, who volunteered to participate as subjects in the study, were given a low-protein diet (based on staple foods habitually consumed by subjects) for 10 d. Mean daily total protein intake was 4.68 g while that of energy was 0.2 MJ/kg body-weight. After an initial 5 d adaptation period, 24 h urine and faeces were collected in marked containers for five consecutive days for N determination. N losses from the skin were also determined in the village adults.3. Mean daily urinary, faecal and sweat N losses (mg N/kg body-weight) were 45.88 (SD 4.84), 21.79 (SD4.19), and 7.46 (SD1.71) from the village adults. The corresponding urinary and faecal N losses from the university students were 43.45 (SD 2.28) and 18.32 (SD4.66) (sweat N loss not measured). Thus the total daily obligatory N losses (per kg body-weight) from the village adults and university students were 75.13 and 69.23 mg N respectively (assuming a sweat N loss of 7.46 mg for the university students). After adjusting for requirement and making a 30% allowance for individual variability, the safe level of protein intake was calculated to be 0.78 and 0.73 g protein/kg body-weight for the village men and university students respectively.4. These values suggest that the Joint FAO/WHO ad hoc Expert Committee (1973) safe allowance of 0.57 g egg protein/kg per d is not sufficient for most young adults in this environment when energy intake is adequate.

scholarly journals Nitrogen budget in recirculating aquaponic systems with different fish stocking density

2020 ◽  
Vol 15 (3) ◽  
Author(s):  
Carmelo Maucieri ◽  
Carlo Nicoletto ◽  
Giampaolo Zanin ◽  
Marco Birolo ◽  
Gerolamo Xiccato ◽  
...  
Keyword(s):  
Stocking Density ◽  
N Balance ◽  
N Recovery ◽  
Fish Biomass ◽  
Fish Feed ◽  
N Loss ◽  
Fish Stocking ◽  
N Losses ◽  
Total N ◽  
N Input

As in any agroecosystem, also in aquaponics the nitrogen (N) balance represents an important tool to evaluate sustainability, and to identify factors that can improve N use efficiency (NUE) and reduce N losses. In this respect, fish stocking density has been little investigated, hence this research aimed to evaluate the N balance of a low technology aquaponic (AP) system managed at two fish densities in comparison with a hydroponic system (HP). In the fish tanks common carp at two initial stocking densities were reared (2.5 and 4.6 kg m–3 in low and high AP, hereafter named APL and APH, respectively) and the vegetated sector was cultivated with a leafy vegetable crop succession (Catalogna chicory, lettuce, Swiss chard). The N balance considered N input as fish feed or fertiliser, and N content in the initial water and the N output as N in the incremented fish biomass, in the harvested vegetables, in the sediments, and in the remaining water. Total N loss was estimated by difference. The total N input and the N loss through gas emission in the atmosphere were much higher in AP than in HP, particularly at high stocking density. The opposite trend was observed for the N input recovered in vegetable aboveground biomass. The N input recovered as fish biomass was slightly higher in APL compared to APH. The better results of APL than APH suggest that in low-tech AP system lower initial fish density should be adopted at the system start up to maximise both production and N recovery.

scholarly journals Influence of forage level and corn grain processing on whole-body urea kinetics, and serosal-to-mucosal urea flux and expression of urea transporters and aquaporins in the ovine ruminal, duodenal, and cecal epithelia

2020 ◽  
Vol 98 (4) ◽  
Author(s):  
Karen A Scott ◽  
Gregory B Penner ◽  
Timothy Mutsvangwa
Keyword(s):  
Mrna Expression ◽  
Dietary Factors ◽  
Mrna Abundance ◽  
N Balance ◽  
Whole Body ◽  
Total N ◽  
Messenger Ribonucleic Acid ◽  
Grain Processing ◽  
Urea Kinetics ◽  
Corn Grain

Abstract The objectives were to determine the effects of forage level and grain processing on whole-body urea kinetics, N balance, serosal-to-mucosal urea flux (Jsm-urea), and messenger ribonucleic acid (mRNA) abundance of urea transporter-B (UT-B; SLC14a1) and aquaporins (AQP) in ovine ruminal, duodenal, and cecal epithelia. Thirty-two wether lambs were blocked by body weight into groups of four and assigned to one of four diets (n = 8) in a 2 × 2 factorial design. Dietary factors were forage level (30% [LF] vs. 70% [HF]) and corn grain processing (whole-shelled [WS] vs. steam-flaked [SF]). Four blocks of lambs (n = 4) were used to determine urea kinetics and N balance using 4-d [15N15N]-urea infusions with concurrent fecal and urine collections. Lambs were killed after 23 d of dietary adaptation. Ruminal, duodenal, and cecal epithelia were collected to determine Jsm-urea and mRNA abundance of UT-B and AQP. Lambs fed LF had greater intakes of dry matter (DMI; 1.20 vs. 0.86 kg/d) and N (NI; 20.1 vs. 15.0 g/d) than those fed HF (P &lt; 0.01). Lambs fed SF had greater DMI (1.20 vs. 0.86 kg/d) and NI (20.6 vs. 14.5 g/d) than those fed WS (P &lt; 0.01). As a percentage of NI, total N excretion was greater in lambs fed HF compared with those fed LF (103% vs. 63.0%; P &lt; 0.01) and was also greater in lambs fed WS compared with those fed SF (93.6% vs. 72.1%; P = 0.02). Retained N (% of NI) was greater in lambs fed LF compared with those fed HF (37.0% vs. −2.55%; P &lt; 0.01). Lambs fed SF had a greater (P = 0.02) retained N (% of NI; 28.0% vs. 6.50%) compared with those fed WS. Endogenous urea production (UER) tended (P = 0.09) to be greater in lambs fed HF compared with those fed LF. As a proportion of UER, lambs fed HF had a greater urinary urea-N loss (0.38 vs. 0.22) and lower urea-N transferred to the gastrointestinal tract (GIT; 0.62 vs. 0.78) or urea-N used for anabolism (as a proportion of urea-N transferred to the GIT; 0.12 vs. 0.26) compared with lambs fed LF (P &lt; 0.01). Ruminal Jsm-urea was unaffected by diet. Duodenal Jsm-urea was greater (P &lt; 0.01) in lambs fed HF compared with LF (77.5 vs. 57.2 nmol/[cm2 × h]). Lambs fed LF had greater (P = 0.03) mRNA expression of AQP3 in ruminal epithelia and tended (P = 0.06) to have greater mRNA expression of AQP3 in duodenal epithelia compared with lambs fed HF. Expression of UT-B mRNA was unaffected by diet. Our results showed that feeding more ruminally available energy improved N utilization, partly through a greater proportion of UER being transferred to the GIT and being used for anabolic purposes.

The protein requirement for maintenance in the White-crowned Sparrow, Zonotrichia leucophrys gambelii

1993 ◽  
Vol 71 (10) ◽  
pp. 2111-2120 ◽  
Author(s):  
Mary E. Murphy
Keyword(s):  
Amino Acid ◽  
Body Mass ◽  
Dietary Protein ◽  
Wild Birds ◽  
N Balance ◽  
N Loss ◽  
Protein Requirement ◽  
Zonotrichia Leucophrys ◽  
Protein Requirements ◽  
Zonotrichia Leucophrys Gambelii

Assumptions about potential mismatches between protein demand and protein availability are implicit in many hypotheses pertaining to the ecology of wild birds. However, few direct measures of the protein requirements of wild birds have been made. I evaluated the requirement for protein for maintenance of a wild granivorous passerine, the White-crowned Sparrow (Zonotrichia leucophrys gambelii). I estimated protein requirement from measures of endogenous nitrogen (N) loss, N balance, and changes in body mass in wintering adult birds. The experimental birds were kept indoors at 23 °C (8.5 h light: 15.5 h dark) and fed semisynthetic diets that differed only in their concentrations of protein (0–17.3%) and starch, which were reciprocally adjusted. The amino acid profiles of the protein in the diets were identical and were formulated to match the average amino acid profile of the mixed proteins of a diet containing grains, seeds, insects, and fruits. In White-crowned Sparrows, the protein requirements for maintenance of body mass (366 mg/d) and a positive N balance equal to that of birds ingesting the acclimation diets (436 mg/d) were 7.3 and 8.7% protein, respectively, in a diet containing 12.4 kJ apparent metabolizable energy per gram dry mass. The estimated minimum maintenance requirement for protein for N equilibrium, derived from regressing N excretion on N intake, equalled 264 mg protein/d, or ca. 5.3% dietary protein. Measures of endogenous N loss (endogenous urinary N loss plus metabolic fecal N loss) equalled 14.7 mg N/d, indicating that White-crowned Sparrows need to replace at least 92 mg body protein/d. Dietary protein content had little influence on the birds' utilization of dietary energy and daily metabolized energy. The apparent contradiction in the requirement for a positive N balance to maintain body mass is discussed.

scholarly journals Criteria and markers for protein quality assessment – a review

2012 ◽  
Vol 108 (S2) ◽  
pp. S222-S229 ◽  
Author(s):  
Daniel Tome
Keyword(s):  
Amino Acid ◽  
Nitrogen Balance ◽  
Protein Quality ◽  
The Body ◽  
Food Sources ◽  
Whole Body ◽  
Protein Nitrogen ◽  
Protein Requirements ◽  
Indispensable Amino Acid ◽  
Body Level

Dietary proteins are found in animal products, plant products and single-cell organisms. Proteins are present in variable proportions in these different food sources and the different proteins also differ in their amino acid composition, dietary indispensable amino acid content and physico-chemical properties. Different criteria can be used to define dietary protein requirements and different markers can be used to assess nutritional protein quality according to the criteria used for protein requirement estimation. The current approach to determining protein requirements is related to nitrogen balance and the dietary indispensable amino acid score approach relates protein quality to the capacity of protein to allow reaching nitrogen balance by providing nitrogen and indispensable amino acids. A second approach considers more directly protein nitrogen utilization by the body and includes measurement of protein digestibility and of the efficiency of dietary nitrogen retention at maintenance or for protein deposition at the whole body level or in more specific body areas. Another approach is related to protein turnover and protein synthesis in relation to maintenance and/or efficiency for deposition or development (growth) at the whole body level or for different and more specific target tissues such as muscle or bone. Lastly, protein quality can also be evaluated from different markers used as risk factors for metabolic dysfunction and disorders related for instance to insulin resistance, diabetes and obesity or cardio-vascular disease. The accuracy and relevance of these different approaches is discussed regarding the capacity of the different protein sources (i.e. animal as meat, milk or eggs, legume as soya or pea, or cereal as wheat or rice) to satisfy protein requirements according to these different criteria and markers.

A Simple and Inexpensive Clinical Whole Body Counter

1976 ◽  
Vol 15 (05) ◽  
pp. 248-253
Author(s):  
A. K. Basu ◽  
S. K. Guha ◽  
B. N. Tandon ◽  
M. M. Gupta ◽  
M. ML. Rehani
Keyword(s):  
The Body ◽  
Whole Body ◽  
Vitro Assay ◽  
Body Counter ◽  
Optimum Parameters ◽  
Whole Body Counter ◽  
Single Detector ◽  
Background Index ◽  
Iodide Crystal

SummaryThe conventional radioisotope scanner has been used as a whole body counter. The background index of the system is 10.9 counts per minute per ml of sodium iodide crystal. The sensitivity and derived sensitivity parameters have been evaluated and found to be suitable for clinical studies. The optimum parameters for a single detector at two positions above the lying subject have been obtained. It has been found that for the case of 131I measurement it is possible to assay a source located at any point in the body with coefficient of variation less than 5%. To add to the versatility, a fixed geometry for in-vitro counting of large samples has been obtained. The retention values obtained by the whole body counter have been found to correlate with those obtained by in-vitro assay of urine and stool after intravenous administration of 51Cr-albumin.

Features of development of functional overstrain at workers of physical work

2020 ◽  
pp. 643-643
Author(s):  
A. V. Kapustina ◽  
V. V. Elizarova ◽  
O. V. Bykova
Keyword(s):  
Functional State ◽  
The Body ◽  
Physical Work ◽  
Manual Labor ◽  
Production Studies ◽  
Professional Groups

The results of the production studies of professional groups of manual labor (stone saws, packers, slingers) are presented. It is shown that a change in the functional state of the body of workers leads to the development of fatigue and overstrain of the body systems of workers.

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