Nitrogen Gain Research Articles

Dietary cysteine/methionine ratios and taurine supplementation: effects on rat growth, amino acids and bile acids

Diets containing 15% protein (casein plus arginine, threonine and tryptophan), 20% fat (soybean-coconut oil) and adequate amounts of minerals and vitamins were supplemented with methionine and/or cysteine to provide cysteine/methionine ratios of 0.2, 1.0 and 2.0 simulating those in various dietary proteins, human milk and infant formulas. The dietary cysteine/methionine ratios had significant (P<0.05) effects on 2-wk weight gain and levels of blood serum urea nitrogen (BUN) and taurine-conjugated bile acids in bile of weanling rats, indicating an inferior nutritional quality of the low cysteine/methionine diet (0.2) compared to the medium (1.0) or high (2.0) cysteine/methionine diet. Taurine supplementation increased levels of taurine in liver, serum and urine of rats fed all three cysteine/methionine diets. Taurine supplementation also increased levels of taurine-conjugated bile acids in the bile of rats fed the low cysteine/methionine diet but produced fatty livers in those fed the high cysteine/methionine diet.

Nitrogen Budget for the Rotifer Brachionus plicatilis

AbstractNitrogen ingested by the rotifer, Brachionus plicatilis (S type) is balanced by gain in body nitrogen (including reproduction), soluble excreted nitrogen, and nitrogen as egested feces. Every term in the budget was estimated independently, and measured as directly as possible. A comparison of the observed and calculated nitrogen as egested feces yielded a satisfactory result.The nitrogen ingested by the rotifer was distributed as follows: 15.6% for growth and reproduction, 42.0% for metabolic excretion, and 42.4% as feces. From these results, it was concluded that a large proportion (84%) of the nitrogen ingested by the rotifer is transferred to water in various forms and may cause deterioration of the water quality.

Energy value of cassava for young swine.

A comparative slaughter experiment was conducted to determine the energy values of cassava chips for weanling pigs. A basal, highly fortified diet was fed to all pigs at 3% body weight daily. Treatments consisted of the addition of cassava chips at 0, 1, and 2% of body weight daily. The apparent digestion coefficients (ADC) for dry matter and energy increased but the ADC for nitrogen decreased with the addition of cassava chips to the basal diet. Digestible energy per gram decreased linearly and quadratically (P less than .01), but metabolizable energy and net energy per gram remained constant with the addition of cassava chips. Metabolizable energy as a percentage of digestible energy increased linearly and quadratically (P less than .01) with the addition of cassava chips to the basal diet. Daily gain of nitrogen, ether extract, and energy increased linearly (P less than .01) as cassava chips were added to the basal diet, but daily gain of ash remained relatively constant. Pooled energy values determined for cassava chips in kcal/g of dry matter were: gross energy, 4.04; digestible energy, 3.58; metabolizable energy, 3.48; nitrogen-corrected metabolizable energy, 3.22; and net energy, 2.57. Net energy of cassava chips for weanling pigs is close to that of corn.

The effect of an anabolic steroid, methenolone enanthate, on growth, body composition and skeletal muscle protein synthesis in the growing rat

The effect of Primobolan (methenolone enanthate; 10 mg kg −1 thrice-weekly) on total body nitrogen, potassium, phosphorus, and body-weight, muscle protein synthesis and food conversion efficiency was measured in Wistar rats during the period from weanling to maturity (22 to 64 days of age). Treated male rats exhibited a lower rate of weight gain, increased kidney weight and decreased testicular weight when compared with controls. No differences in total nitrogen, potassium or phosphorus were observed. Treated female rats had significantly increased body-weight, total body nitrogen, phosphorus, and potassium compared with female controls although, when expressed as a percentage of body weight, phosphorus content was higher in controls. Treated female rats had increased food conversion efficiency expressed relative to total body weight gain or total body nitrogen gain. Rates of synthesis of mixed skeletal muscle protein, measured at the conclusion of the study, indicated that treated females had a significantly increased rate of synthesis when compared to female controls. There was no significant difference between treated male rats and control animals.

Insect capture and growth of the insectivorous Drosera rotundifolia L.

Rates of insect capture increased with leaf area in the insectivorous plant Drosera rotundifolia, and growth of new leaves was related to insect capture. However, increased leaf growth was counterbalanced by leaf abscission which was in turn related to insect capture and leaf growth. Leaf loss equaled leaf growth in plants having natural rate of insect capture. A large proportion of the nitrogen gain from prey was stored in the hypocotyl; it was estimated from feeding experiments that about 24% to 30% of the nitrogen stored in the hypocotyl after winter originated from insect capture in the previous season. The effect of insect capture is discussed in relation to the life cycle of Drosera.

Can intensively managed forest ecosystems be self-sufficient in nitrogen?

A simple input-outpu model was constructed to evaluate the long-term net nitrogen (N) gain or loss or N self-sufficiency of several silvicultural systems. In general, short-rotation, whole-tree-harvest systems are not self-sufficient in N. If they include an active biological nitrogen fixation (N 2 fixation) component, however, they are highly N self-sufficient even when they sustain large losses of N in harvested biomass. Forestry systems, with or without substantial N 2 fixation, appear to be greatly superior in this respect to most annual agricultural crops with or without N 2 fixation. All N inputs and outputs must be measured in field experiments, however, before N self-sufficiency can be accurately evaluated. Better estimates of loss through harvest removal, and gain through N 2 fixation and atmospheric inputs, over more than one rotation are particularly needed.

Use of a Four-Parameter Logistic Model to Evaluate the Quality of the Protein from Three Insect Species when Fed to Rats

The quality of three insect protein sources [Mormon cricket meal (MCM), house cricket meal (HCM) and Eastern tent caterpillar meal (TCM)] was evaluated relative to that of lactalbumin (LA) and soy protein (SP) by using both amino acid analysis and a rat bioassay. The amino acid pattern of the three insect meals indicated that methionine should be the first limiting amino acid for growing rats. In the rat bioassay, weanling Sprague-Dawley rats were fed graded levels of the five proteins in purified diets and the response (weight or nitrogen gain) evaluated as a function of nitrogen intake. The individual nitrogen intake-animal response results could be described by a series of curves using a four-parameter logistic model. The use of parameter sharing permitted the full range of responses to be described so that statistical differences between the dose-response curves could be identified. When used for either weight maintenance, nitrogen equilibrium, maximum weight gain or maximum nitrogen retention, the five protein sources could be ranked in the following order: LA greater than HCM greater than MCM = SP greater than TCM. Relative to lactalbumin, the value of all four protein sources decreased with increasing nitrogen intake. The low values obtained for TCM may have been related to factors other than protein quality. The results of this study indicate that some insect proteins are equivalent or superior to soy protein as a source of amino acids for growing rats.

A regional analysis of total nitrogen in an agricultural landscape

Techniques for modeling spatial variability in the loss, gain, and storage of total nitrogen (N) in an agricultural landscape were developed utilizing a geographic information system (GIS) based on the Map Analysis Package (C.D. Tomlin, Yale University). The study area is a well-monitored portion (upper 114.9 km2) of the Little River Watershed, located near Tifton, Georgia, U.S.A. On the basis of measured N in the soil and vegetation, and the gains and losses of N by stream discharge, fertilizer, precipitation, N fixation, crop harvest, etc., it was possible to quantify and map source and sink regions of Total N, and to calculate a mass balance of N for an entire year. Results indicate massive flows of N, especially from anthropogenic sources. However, for the watershed as a whole, the N is virtually in balance with a small accretion occurring mostly in the riparian zones. Stream discharge of total N indicates that this landscape is well-buffered against excessive losses of N despite the large agricultural inputs.

Cultivation and use of lesser-known plants of food value by tribals in north-east India

The role of lesser-known crops, Digitaria cruciata (Nees) A. Camus var. esculenta Bor., Flemingia vestita Benth ex Bax. and Perilla ocimoides L. cultivated by the Khasis at higher elevations of Meghayala, and Amaranthus viridis L., Chenopodium ambrosioides L., Coix lacrymajobi L., Dioscorea spp., Fagopyrum tataricum Gaertn., Panicum miliaceum L., Perilla ocimoides and Setaria italica (L.) Beauv. cultivated by the Nishis, the Hill Miris and the Sulungs of Arunachal Pradesh in north-east India were evaluated from an ecological and socio-economical point of view. Digitaria cruciata var. esculenta is largely cultivated for manure by composting the biomass, although the grains are also consumed. The role of a lesser-known legume, F. vestita, was evaluated for its ability to improve soil nitrogen status. Mixed cropping with F. vestita was found to give better economic returns, apart from improved soil fertility with a net gain in nitrogen of up to 250 kg ha −1 year −1. The importance of the lesser-known crops varies considerably depending upon the tribe, but they meet the needs of the people during the summer and rainy months, when availability of traditional crops is limited.

Pre-operative parenteral nutrition in patients with oesophageal cancer: a prospective, randomised clinical trial

A prospective randomised clinical trial was conducted to examine the efficacy of 2 weeks pre-operative parenteral nutrition (PPN) for the prevention of complications following surgery for oesophageal cancer. Forty patients were studied, the diet of twenty being supplemented by pre-operative parenteral nutrition. There were no significant differences in age, nutritional status, tumour staging and histology between the two groups of patients. The use of PPN resulted in a significant gain in body weight and nitrogen but failed to produce an overall reduction in post-operative morbidity and mortality rates. However patients receiving PPN exhibited two types of changes in serum albumin levels. Those with a fall in serum albumin levels associated with an increase in body weight (indicating an expansion of extracellular volume) had a significantly higher incidence of post-operative pulmonary complications than the group exhibiting a rise in serum albumin levels concomitant with increase in body weight. These data suggested that two weeks PPN might not be adequate in certain patients and a longer period of PPN is required. They also show no clinical benefit from the routine use of pre-operative parenteral nutrition in all patients, but do not exclude benefit in selected groups.

Rhoads lecture--1988. Bulk or bounce--the object of nutritional support.

Wasting of muscle and a negative nitrogen balance are obvious effects of malnutrition, and have led to the use of anthropometric measurements and nitrogen balance for its assessment. A positive nitrogen balance and an increase in limb muscle circumference are believed to be solid indices of the beneficial effects of nutritional support. In experiments with growing rats and in young children, nitrogen retention and growth are recognized to be the desirable effects of optimal nutritional intake. This concept has been applied to malnourished adult humans (nongrowing) who have been considered potentially able to "regrow" the lost tissue. Although it is true that patients receiving long-term (greater than 6 months) home total parenteral nutrition (TPN), gain body weight and nitrogen over many months and years of observation, these processes are not seen during shorter (less than 40 days) periods of nutritional intervention given in hospital. Despite adequate intakes of nitrogen and calories, little or no significant increase in total body nitrogen is seen in a variety of patients receiving TPN in hospital over several weeks, but nutritional support does appear to improve outcome in the form of reduced complications after a period of support so short that body composition is barely altered. For example, Young and Hill showed that although amino acids and amino acids plus calories both resulted in equivalent sparing of body nitrogen, the latter was associated with quicker wound healing and fewer complications. Thus, the outcome and body composition data suggest that reversal of the adverse effects of malnutrition is not based on improvement of the traditional parameters of nutrition, such as gain in body nitrogen, or a demonstrable increase in muscle mass, or in plasma proteins. On the basis of the foregoing evidence, there are grounds for suspecting that functional abnormalities in adult humans may not be the result of simple loss of lean tissue and therefore may recover before such lean tissue is regained. This hypothesis is supported by the observation of Klidjian et al who showed that muscle force is a good measure of outcome. One of the major organ systems of the human body is the musculoskeletal system, and therefore it would seem important to determine the effect of malnutrition on that system. Previous studies of muscle function have been largely related to the examination of fatigue, myopathy, and endocrine-metabolic abnormalities. Subsequently we undertook initial studies of muscle function in very malnourished patients as outlined below.

Use of a Four-Parameter Logistic Model to Evaluate the Protein Quality of Mixtures of Mormon Cricket Meal and Corn Gluten Meal in Rats

Weanling Sprague-Dawley rats were fed diets containing corn gluten meal (CGM), Mormon cricket meal (MCM), MCM supplemented with methionine (MCM + Met) or CGM-MCM mixtures as the sole source of dietary protein in purified diets. Animal response (weight or nitrogen gain) was analyzed as a function of nitrogen intake and described by a series of curves using a four-parameter logistic model. Parameter sharing was used to differentiate statistically between the response curves. When used for maximum nitrogen retention the quality of the protein sources could be ranked as follows: MCM + Met > 40 CGM-60 MCM > 50 CGM-50 MCM > 60 CGM-40 MCM > MCM > CGM. When used for maximum weight gain the ranking was as follows: MCM + Met > 40 CGM-60 MCM > 50 CGM-50 MCM = 60 CGM-40 MCM > MCM > CGM. The rankings of the protein sources when used for weight maintenance or nitrogen equilibrium were similar to those seen for maximum weight or nitrogen gain except for the ranking of MCM, which changed from fifth to first. These results show MCM to be a good quality protein source and that methionine is the first limiting amino acid when used for growth but not for maintenance. The shape of the response curves was dependent upon the response criteria as well as the source of dietary protein. The factors that may affect the shape of the dose-response curves and the application of nonlinear models toward animal feeding programs are discussed.

Effect of protein and lysine levels in the diet on body gain composition and energy utilization in growing pigs.

Eight replicates of four Large White littermate female pigs were used to evaluate the effect of protein and lysine levels in the diet on the efficiency of protein and energy utilization. In each replicate, one pig was slaughtered at about 20 kg live weight and the others received three diets that contained (per Mcal digestible energy) 37.5 and 2.00 g (diet pl), 37.5 and 2.35 g (diet pL) or 45.0 and 2.35 g (diet PL) of digestible protein and lysine, respectively. Pigs were slaughtered after a 7-wk period. Tissue and chemical composition of the gain and energy and nitrogen gain were determined by using the comparative slaughter technique. Metabolizable energy (ME) intakes were similar in the treatments. Pigs fed the pl diet had a smaller body weight and muscle gain and retained less nitrogen and more lipids than pigs fed pL and PL diets. The decrease in the level of nonessential nitrogen in the diet (pL vs PL) did not affect body weight and muscle gain and the amount of nitrogen retained in muscle tissues. However, pigs given the PL diet had a higher total nitrogen retention and a lower fat deposition and exhibited a higher heat production. For each gram of additional protein catabolized for energy purposes (PL vs pL), heat production was increased by 1.8 kcal. The amount of lysine per unit of muscle gain (38 g/kg) or protein deposited (120 g/kg) was independent of protein and lysine levels in the diet. Estimates of energy (indirect calorimetry) and nitrogen (balance technique) retention were also obtained on the same animals; results were comparable with data obtained by direct measurements.

Grain Yield ofPennisetum americanumAdjusts to Nitrogen Supply by Changing Rates of Grain Filling and Root Uptake of Nitrogen

Coaldrake, P. D., Pearson, C. J. and Saffigna, P. G. 1987. Grain yield of Pennisetum americanum adjusts to nitrogen supply by changing rates of grain filling and root uptake of nitrogen.—J. exp. Bot. 38: 558-566. Pearl millet (Pennisetum americanum (L.) Leeke) was grown in containers at three constant rates of nitrogen supply or with the nitrogen supply increased from the lowest to the highest rate during panicle differentiation or at anthesis. We measured the rate and duration of nitrogen and dry weight gain by individual grains and nitrogen (15N) uptake by roots and its distribution during grain filling. The total amounts of nitrogen and dry weight in all grain per plant at the lowest nitrogen supply were 8% and 14% respectively of plants grown continuously at the highest rate of nitrogen. This was because low rates of nitrogen supply reduced grain number, mean grain weight and the nitrogen content of each individual grain. The amino acid composition of the grain protein was affected only slightly by nitrogen treatments. Rates of grain growth were sensitive to nitrogen supply whereas the duration of nitrogen movement to the grain was not. Nitrogen uptake by roots continued throughout grain filling; rates of uptake per g root in plants given least nitrogen were one-half those of plants given the highest amount of nitrogen. A change from lowest to highest nitrogen supply at panicle differentiation increased the uptake of nitrogen by roots and the rates of growth of individual grains, to the rates observed in plants which had been supplied continuously with the highest nitrogen. When the change in supply was made at anthesis there was rapid movement of nitrogen into the plant but this was not translated into more rapid grain growth.

Requirement for Sulfur-Containing Amino Acids in Infancy

A series of studies designed to define the requirement of normal infants for sulfur-containing amino acids (methionine, cystine) was conducted with formulas providing 3.0, 2.8, 2.6, 2.2 or 1.8 g of isolated soy protein per 100 kcal. The formulas were fed with or without a methionine supplement. Adequacy of the diet was determined by measurement of growth, serum chemical indices and nitrogen balance. Nitrogen balance demonstrated a beneficial effect of methionine supplementation only at the lowest protein concentration (1.8 g/100 kcal). However, measurement of weight gain and/or serum concentrations of urea nitrogen and albumin clearly showed a beneficial effect of methionine supplementation at protein concentrations of 2.2 and 2.6 g/100 kcal. Intakes of sulfur-containing amino acids of 435 and 495 µmol/100 kcal therefore appear inadequate. At higher intakes of protein (2.8 and 3.0 g/100 kcal) there was no beneficial effect of methionine supplementation. Possible exceptions were male infants provided with 3.0 g protein per 100 kcal, in whom weight gain between 8 and 56 d of age was significantly (P < 0.05) greater with than without a methionine supplement. Based on intakes of sulfur-containing amino acids from the formula providing 2.8 g of isolated soy protein per 100 kcal without methionine supplementation, we conclude that for male infants older than 56 d the requirement for sulfur-containing amino acids is no more than 588 µmol/100 kcal when intake of methionine is 264 µmol/100 kcal. However, it seems possible that such intakes fail to meet the requirement in male infants less than 56 d of age. For female infants, regardless of age, 533 µmol/100 of sulfur-containing amino acids per 100 kcal meet the requirement when intake of methionine is 239 µmol/100 kcal.

Nitrogen Transformation in Swine Manure in an Oxidation Ditch Under Aerobic Conditions

ABSTRACT SWINE manure was treated in an oxidation ditch system under aerobic condition for odor control. The effects of manure concentration and retention time on the concentration of various nitrogenous compounds in the oxidation ditch were evaluated. Three manure concentrations (50, 33 and 25%, i.e. manure diluted 1:1, 1:2 and 1:3 manure:water); and four retention times (6, 12, 18 and 24 h) were studied. The total solids in the manure were 6, 4 and 3% respectively. The reductions in the total Kjeldahl nitrogen and ammonium nitrogen and the gain in organic nitrogen were related to both the manure concentration and retention time. The reduction in ammonium nitrogen was due to the processes of nitrification, ammonium assimilation and ammonia volatilization.

Rearing of coregonid ( Coregonus schinzi palea Cuv. et Val.) larvae using dry and live food : II. Oxygen consumption and nitrogen excretion

Postprandial metabolic changes in 5-week-old coregonid fry were measured after feeding with live food, Artemia nauplii and three compound dry diets. Growth rates of fish were different and so were the mean weights of the different groups of fish used in these studies; 167 mg for fry fed Artemia and 53, 104 and 142 mg for fish fed diets 1, 2 and 3 respectively. During the week preceding the measurements, the growth rate was 8.12, 4.54, 6.51 and 9.03% day −1 respectively. There was an increase in ammonia and urea excretion in fed fish in comparison with fasted controls and, in the case of urea, this difference was maintained over 14 h after a meal at 13.5°C. An increase in nitrogen (ammonia + urea) excreted after 2 h of feeding in comparison with unfed fish accounted for 9.16–36.92% of nitrogen consumed. During the 5th week of the experiment, nitrogen retention (the proportion of nitrogen gain to nitrogen consumed) amounted to 38.2% in fish fed Artemia and between 11.5 and 20.9% in fish fed dry diets. Postprandial increase in oxygen consumption (specific dynamic action, SDA) was separated from an increase due to activity. SDA accounted for 28.7% of the energy consumed in fish fed live Artemia, whereas in fish fed artificial diets, the SDA was inversely related to their growth rate, and accounted for 4.9–12.7% of energy intake.

Phytochrome Regulation of Biochemical and Enzymatic Changes During Senescence of Excised Rice Leaves

The effect of brief irradiation with red and/or far-red light in regulating the senescence of excised rice ( Oryza sativa L. cv. Ratna) leaves was studied. Red light was effective in arresting the loss of chlorophyll and protein and the gain of α-amino nitrogen. Total soluble sugar and non-reducing sugar content decreased during the senescence of leaves kept in continuous darkness (control) whereas reducing sugar content initially increased and subsequently decreased. Red light was also effective in arresting the loss of decreasing total soluble sugar and non-reducing sugar levels and rise in the reducing sugar levels. Decrease in the catalase and alkaline PPase activities and increase in the peroxidase and acid PPase activities was arrested by red light irradiation during excised leaf senescence. On the other hand, a brief irradiation with far-red light accelerated the senescence process by exhibiting the reverse effect as compared to red light irradiation. The effect of red light was almost nullified by a consecutive brief irradiation with far-red light. The results suggest that the enhanced biochemical and enzymatic changes during rice leaf senescence by far-red light and their retardation by red light is presumably mediated by the phytochrome system.

15N Dilution technique of assessing the contribution of nitrogen fixation to rice plant

Abstract An attempt to correlate the positive nitrogen balance in the rice-soil system with 15N dilution in the rice plant was done to see if isotope dilution can be used to assess the contribution of nitrogen fixation to nitrogen nutrition of rice. 15N ammonium sulfate and sucrose were added to the moist soil in pots to label biomass nitrogen fraction, and then the soil was air dried. It was moistened again, and planted to two crops of dryland rice or wetland rice. Dryland rice bad lower positive nitrogen balance and much higher 15N content than wetland rice. The rice-soil !Wstem with higher nitrogen gain had lower 15N content in the rice plant, suggesting inverse relationship of total nitrogen balance and 15N dilution. When the surface of pots was covered with black cloth, to suppress photodependent N2 fixation, no significant nitrogen gain was observed after two crops of rice. Significant gains were found in the rice-flooded soll system exposed to light and the 15N contents of plants decreased in allowing photodependent N3 fixation by blue-green algae or Azolla-Anabaena symbiosis. Contribution of plant nitrogen derived from photodependent N2 fixation was estimated to be 20-30% of the positive nitrogen gain in the system by the UN dilution technique using the rice-covered soil as reference system. Balance data of total nitrogen and UN enabled the estimation of the gross nitrogen gain in the rice-soil system UN dilution technique is useful in assessing the contribution of Nz fixation to nitrogen nutrition of wetland rice if proper reference system is taken.

Effects of an anabolic steroid on plasma amino acids, proteins, and body composition in patients receiving intravenous hyperalimentation.

In this controlled trial we have studied the effect of anabolic steroid on ill surgical patients receiving intravenous hyperalimentation. Body composition, plasma proteins, and amino acids were compared in each of two groups of 12 patients before and after 14 days of intravenous feeding. The patients in one group were given 100 mg of nandrolone decanoate at the commencement of study and again one week later. Body weight, muscle (AMC), plasma transferrin, prealbumin, and retinol-binding protein were increased comparably in both groups. An apparent gain in total body nitrogen was not significant. However, anabolic steroid caused greater gain of water requiring a more liberal use of diuretics, but prevented the gains of fat, triglyceride and insulin that occurred in the control group. Most plasma amino acids increased due to intravenous hyperalimentation but decreased in patients given anabolic steroid. It is concluded that in patients who may be in the catabolic phase of recovery anabolic steroid probably enhances amino acid and water uptake by tissues and increases the utilization of fat but, does not promote any greater increase in "visceral" proteins than during intravenous hyperalimentation alone.