Feeding Urea Research Articles

Splanchnic metabolism of nitrogenous compounds and urinary nitrogen excretion in steers fed alfalfa under conditions of increased absorption of ammonia and L-arginine supply across the portal-drained viscera1,2,3

Effects of increased ammonia and/or arginine absorption across the portal-drained viscera (PDV) on net splanchnic (PDV and liver) metabolism of nitrogenous compounds and urinary N excretion were investigated in six catheterized Hereford x Angus steers (501 +/- 1 kg BW) fed a 75% alfalfa:25% (as-fed basis) corn-soybean meal diet (0.523 MJ of ME/[kg BW(0.75).d]) every 2 h without (27.0 g of N/kg of dietary DM) and with 20 g of urea/kg of dietary DM (35.7 g of N/kg of dietary DM) in a split-plot design. Net splanchnic flux measurements were obtained immediately before beginning and ending a 72-h mesenteric vein infusion of L-arginine (15 mmol/h). For 3 d before and during arginine infusion, daily urine voided was measured and analyzed for N composition. Feeding urea increased PDV absorption (P < 0.01) and hepatic removal (P < 0.01) of ammonia N, accounting for 80% of increased hepatic urea N output (P < 0.01). Numerical increases in net hepatic removal of AA N could account for the remaining portion of increased hepatic urea N output. Arginine infusion increased hepatic arginine removal (P < 0.01) and hepatic urea N output (P < 0.03) and switched hepatic ornithine flux from net uptake to net output (P < 0.01), but numerical changes in net hepatic removal of ammonia and AA N could not account fully for the increase in hepatic urea N output. Increases in urine N excretion equaled quantities of N fed as urea or infused as arginine. Estimated salivary urea N excretion was not changed by either treatment. Urea cycle regulation occurs via a complex interaction of mechanisms and requires N sources other than ammonia, but the effect of increased ammonia absorption on hepatic catabolism of individual AA in the present study was not significant.

Batch and fed-batch cultivations of Spirulina platensis using ammonium sulphate and urea as nitrogen sources

The cyanobacterium Spirulina platensis is an attractive source of chlorophyll, a green pigment used in food, pharmaceutical and cosmetic industries, and other high-value cell components. Moreover, it can be easily and cheaply recovered by filtration from the cultivation medium. In this work, the replacement of potassium nitrate with ammonium sulphate (A) and urea (U) as cheaper nitrogen sources has been investigated: previous research work did in fact demonstrate that urea has no effect on the final chlorophyll content of the cultures. Several batch and fed-batch protocols were tested, modelled and compared in this work for the first time. It was demonstrated that the kinetics of S. platensis growth at 30°C, using urea as nitrogen source, can be comparable and even better than the one achievable with the classic nitrate-based culture media. Adoption of an appropriate slowly increasing urea feeding rate prevented the accumulation of ammonia in the medium as well as its well-known inhibition of biomass growth; therefore, the use of urea should be recognized as a possible way to decrease the costs of a large-scale plant for the production of this cyanobacterium.

The effect of a diet containing excess quickly degradable nitrogen (QDN) on reproductive and metabolic hormonal profiles of lactating dairy cows

The objective of this experiment was to examine the effects of an excess intake of quickly degradable nitrogen (QDN) on metabolic and reproductive parameters in lactating dairy cows. Twenty-two lactating dairy cows were fed a total mixed ration once daily. The control diet was a typical ration for high producing cows in the UK (CP=17.5%, ME=11.8 MJ/kg DM). The cows were randomly divided into two groups, control diet (control; n=12) and excess QDN diet (QDN; n=10). The QDN group was fed an additional 250 g of urea per cow per day, from 10 days before insemination (day 0) until the end of the experiment, 17 days after the second insemination. Ten days before insemination, a synchronized oestrus was induced and the cows inseminated twice, 48 and 72 h after synchronization, with commercial frozen semen from a single sire. Ovaries were scanned using B-mode ultrasonography 10 days before insemination and then daily from 3 days before insemination. Eighteen of the cows (9 control and 9 QDN) were sampled more intensively to determine the pulsatile pattern of secretion of luteinizing hormone (LH) and growth hormone (GH). Cows were slaughtered 17 days after insemination, the reproductive tracts recovered and flushed to retrieve embryos. The excess QDN diet resulted in elevated ( P<0.05) plasma urea concentrations 3 days after starting urea feeding and these were maintained until the end of the experiment. However, the excess QDN diet did not significantly affect daily milk production or plasma concentrations of insulin and IGF-I. The QDN treatment did not significantly affect pulsatile patterns of secretion of LH and GH or the number of small (<0.5 cm diameter) and medium to large follicles (>0.5 cm diameter). Twenty cows ovulated following synchronization (control 11/12; QDN 9/10). There were no significant differences between the control and the QDN groups in the peak concentrations of oestradiol during the follicular phase or in the post-ovulatory pattern of plasma and milk progesterone secretion. Embryos and/or foetal membranes were recovered from 10 cows (5 control and 5 QDN). The results of the current study show that feeding excess QDN, as urea, for 27 days commencing 10 days before insemination had no effect on reproductive or metabolic hormonal parameters. Ovulation and the formation and function of the post-ovulatory corpus luteum were also unaffected by excess QDN. These data suggest that the harmful effects of excess intakes of QDN on fertility occur after 17 days following ovulation.

Kinetics and Bioenergetics of &lt;I&gt;Spirulina platensis&lt;/I&gt; Cultivation by Fed-Batch Addition of Urea as Nitrogen Source

The cyanobacterium Spirulina platensis was cultivated in bench-scale miniponds on bicarbonate/carbonate solutions using urea as nitrogen source. To minimize limitation and inhibition phenomena, urea was supplied semicontinuously using exponentially increasing feeding rates. The average growth rates obtained alternately varying the total mass of urea added per unit reactor volume (275 < mT < 725 mg/L) and the total feeding time (9 < tT < 15 d) clearly evidenced nitrogen limitation for mT< 500 mg/L and excess nitrogen inhibition above this threshold. The time behavior of the specific growth rate at variable urea feeding patterns allowed estimation of the time-dependent Gibbs energy dissipation for cell growth under the actual depletion conditions of fed-batch cultivations. Comparison of the yield of growth on Gibbs energy obtained using either urea or KNO3 pointed to the preference of S. platensis for the former nitrogen source, likely owing to more favorable bioenergetic conditions.

Feeding of Urea Treated Wheat Straw in Saanen Goat Male Kids

This study was conducted to determine the wheat straws treated with urea (0.05 kg/kg straw) and low protein concentrate in Saanen male kids performance. Thirty-two Saanen male kids (16 weeks of age; 16.125 ± 0.5 kg body weight) were used in a completely randomized design and divided into two uniform treatments. 50 kg urea dissolved in 1000 kg water spreaded over 1000 kg wheat straw and stored for 30 days. Each treatment consisted 16 kids during the 16-weeks to compare performance with diets based on wheat straw (WS) supplemented with 12% crude protein (CP) levels of crushed barley-wheat concentrate (50:50) as traditional in Turkey. Treatment I (control) were fed on 500 g. untreated straw (US) and 500 g. crushed barley-wheat concentrate (50:50). Treatment II were fed on urea treated straw (UTS) and crushed barley-wheat concentrate (50:50). At the end of the trial, the findings were not statistically important (p<0.05). In conclusion, supplementation of treated wheat straw (TWS) with a barley-wheat based concentrate support had not positive effect on Saanen kids' performance for 4 months.

Study on the Development of the Optimum Feeding Regimen for Pigs Weaned at 21 Days of Age

This experiment was conducted to investigate the effect of various feeding regimens on growth performance, nutrient digestibilities, nitrogen retention, blood urea nitrogen (BUN) concentration and feed cost in young pigs weaned at 21 days of age. One hundred twenty crossbred pigs (Landrace×Large White×Duroc, average 6.8 kg BW), weaned at 21 days of age, were allotted to 5 treatments in a 5 replicates by a randomized completely block (RCB) design. Treatments were as follow: 1) 1P (1-4 weeks: CP 23% and lysine 1.60%), 2) 2P-I (1 week: CP 23% and lysine 1.60%, 2-4 weeks: CP 21% and lysine 1.45%), 3) 2P-II (1-2 weeks: CP 23% and lysine 1.60%, 3-4 weeks: CP 21% and lysine 1.45%), 4) 2P-III (1-3 weeks: CP 23% and lysine 1.60%, 4 week: CP 21% and lysine 1.45%), 5) 3P (1 week: CP 23% and lysine 1.60%, 2-3 weeks: CP 21% and lysine 1.45%, 4 week: CP 19% and lysine 1.30%). Three different diets were formulated and supplied according to phase feeding programs. Diet 1 contains 23% crude protein and 1.60% lysine, diet 2 contains 21% crude protein and 1.45% lysine and diet 3 contains 19% crude protein and 1.30 lysine, respectively. Although there was no significant difference in growth performances, there was a beneficial effect of 3 phase feeding. The ADG was higher in 3P treatment than other treatments and it was observed clearly in late period (3-4 weeks) than in early period. Also, with increase in age, growth rate of pigs in 3P treatment was higher than that in 1P treatment approximately 37% (p=0.1379). There were no significant differences among all treatments in nutrient digestibility. The concentration of BUN was higher in pigs were fed diet containing 21% crude protein and 1.45% lysine (eg, 2P-1 and 3P) than those supplied diet containing high nutrient value at 2 week. The lowest feed cost/kg weight gain of pigs showed in 3P among treatments (p<0.05) whereas, high feed cost/kg weight gain of pigs was calculated in 1P and 2P-II treatments compared with 2P-I and 2 P-II (p<0.05), because of high milk products were used in those diet. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 10 : 1518-1523)

Carcass Characteristics of Goats Fed Ammoniated Neem (Azadirachta indica) Seed Kernel Cake

The present investigation was carried out to study the affect of feeding urea ammoniated neem kernel meal on carcass characteristics and organoleptic properties of the meat in goats. Eight local weaned kids of 3-4 months age with mean body weight of 7.85±0.42 kg were assigned to two groups of four each in a completely randomised design and were offered diets containing isonitrogenous concentrate mixtures containing either peanut meal or urea ammoniated neem (Azadirachta indica) seed kernel meal (UANSKM) along with ad libitium oat hay or green sorghum as roughage for 13 fortnights. The animals were slaughtered at the end of the experimental period and the carcass characteristics and organoleptic evaluation of the meat was carried out. The carcass characteristics in terms of dressing percentage, meat bone ratio, percent edible and inedible did not differ between the treatments. Similarly the organoleptic characteristics and cooking loss were comparable between the treatments implying that UANSKM can be substituted for peanut meal in goat diets to alleviate the shortage and high cost of peanut meal without affecting meat quality. (Asian- Aust. J. Anim. Sci. 2003. Vol 16, No. 10 : 1451-1454)

Effect of timing of urea feeding on the yield and quality of embryos in lactating dairy cows

High protein diets, which lead to excess production of nonprotein nitrogen such as ammonia and urea, have been associated with reduced fertility in dairy cows. In this study we test the hypothesis that diets containing high levels of quickly degradable urea nitrogen (QDN) compromise embryo development. Lactating dairy cows were fed mixed silage and concentrates twice daily. At 60 days postpartum, a synchronized estrus was induced and the cows were subsequently superovulated and inseminated using a standard protocol. On Day 7 after insemination, the uteri were flushed and embryos retrieved. At the start of treatment, cows were randomly allocated into three nutritional groups: control (CONT, n=8), long (L-) QDN (n=8) and short (S-) QDN (n=9). The L-QDN cows were fed a supplement of urea from 10 days before insemination, and the S-QDN cows were fed the supplement from insemination until embryo collection. Both L- and S-QDN diets produced significant increases in plasma ammonia and urea 3h post-feeding. The S-QDN but not the L-QDN diet was associated with a significant reduction in embryo yield. Embryo quality was also significantly reduced in the S-QDN cows. This study indicates that there is no deleterious effect on the yield and quality of embryos recovered 7 days after breeding when QDN feeding is initiated during the previous midluteal phase. However, introduction of a similar diet 10 days later, at the time of insemination, was deleterious. We suggest that QDN is toxic to embryos but cows can adjust within 10 days.

The Effect and Economic Evaluation of Feeding Urea- Molasses and Urea-Molasses Concentrate With Green Grasses on Milk Production in Buffalo Cows of Bangladesh

The Effect and Economic Evaluation of Feeding Urea- Molasses and Urea-Molasses Concentrate With Green Grasses on Milk Production in Buffalo Cows of Bangladesh

Effects of Feeding Urea and Soybean Meal-Treated Rice Straw on Digestibility of Feed Nutrients and Growth Performance of Bull Calves

The experiment was conducted for a period of 56 days with twelve Bangladeshi bull calves of average body weight of kg. The calves were divided into 3 groups having 4 animals in each. The animals were fed urea-treated rice straw designated as A) 4% urea-treated rice straw, B) 4% urea+4% soybean-treated rice straw and C) 4% urea+6% soybean-treated rice straw. In addition, all the animals were supplied 2 kg green grass, 350 g Til-oil-cake and 100 g common salt per 100 kg body weight of animals. Straw was treated with 4% urea solution and soybean meal at 4 and 6% were added to treated straw and kept for 48 h in double layer polythene bags under anaerobic condition. Urea treatment improved crude protein (CP) content of rice straw from 2.68 to 8.70% and it was further increased by 10.74 and 12.12% with the addition of 4 and 6% soybean meal. Dry matter (DM) intake (kg) was higher (p

Acidosis mediates the upregulation of UT-A protein in livers from uremic rats.

Liver expresses a 49-kD UT-A protein whose abundance is increased by uremia. Chronic renal failure causes acidosis; therefore, the role of acidosis in increasing UT-A abundance was tested. Rats underwent 5/6 nephrectomy, and half were given bicarbonate mixed in their food. Bicarbonate administration significantly increased blood pH. Compared with sham-operated rats, UT-A protein abundance was significantly increased by 50% in livers from uremic, acidotic rats; bicarbonate administration prevented the increase in UT-A protein. To determine whether acidosis alone would increase UT-A protein in liver, rats were made acidotic, but not uremic, by feeding them HCl. HCl-feeding significantly lowered blood pH, increased urea excretion, and increased the abundance of the 49-kD liver UT-A protein by 36% compared with pair-fed nonacidotic rats. HCl-feeding significantly increased the abundance of the 117-kD UT-A1 protein in kidney inner medulla but did not change aquaporin-2 protein. Next, rats were fed urea to determine whether elevated blood urea would increase UT-A protein. However, urea feeding had no effect on UT-A in liver or kidney inner medulla. It was, therefore, concluded that acidosis, either directly or through a change in ammonium concentration, rather than other dietary components, stimulates the upregulation of UT-A protein in liver and kidney inner medulla.

Studies on the Mode of Uptake of Plasma Glucose, Acetate, β-hydroxybutyrate Triglyceride Fatty Acids and Glycerol by the Mammary Gland of Crossbred Holstein Cattle Feeding on Different Types of Roughage

The present experiment was carried out to study the utilization of substrates in the mammary gland of crossbred Holstein Friesian during feeding on different types of roughage. Sixteen pregnant crossbred Holstein heifers consisted of two breed types of eight animals each; Holstein Friesian×Red Sindhi (50:50=50%HF) and Holstein Friesian×Red Sindhi (87.5:12.5=87.5%HF). Animals were divided into four groups of the same breed type in each group which were fed with either rice straw treated with 5% urea or pangola hay (Digitaria decumbens) as the source of roughage throughout the experiments. Four consecutive experimental periods were carried out in late pregnancy (20-23 days before parturition), early lactation (30 days postpartum), mid-lactation (120 days postpartum) and late lactation (210 days postpartum). Measurement of mammary blood flow in combining with measurement of AV difference was performed for the mammary uptake of substrates. In the period of lactation, udder blood flow was nearly three times higher than that of late pregnant period (p<0.05) in both 50%HF and 87.5%HF feeding on either hay or urea treated rice straw. During mid- and late lactation of both groups of 87.5%HF animals, mammary blood flow and milk yield showed decrease when compared to those during the early lactating period while the trends for persistency were apparent in both groups of 50%HF animals throughout experimental periods. The mean arterial plasma concentrations of glucose, acetate, β-hydroxybutyrate and free glycerol in each group remained constant throughout experimental periods. During late pregnancy in all groups, the AV difference and extraction ratio of glucose, β-hydroxybutyrate and triacylglycerol across the mammary gland markedly lowered (p<0.05), which coincided with a lower net uptake by the mammary gland in comparison to the early lactating period. The mean arterial plasma concentration, AV difference and extraction ratio for acetate showed no significant differences between late pregnancy and the early lactating period. The AV difference of free glycerol showed apparent release from mammary tissue during late pregnancy in all groups. In mid- and late lactation, the mammary uptake for glucose, acetate and β-hydroxybutyrate in both groups of 87.5%HF animals showed apparent decrease as compared to that in the early lactating period, whereas no appearances were observed in 50%HF animals feeding either hay or urea treated rice straw. The mean arterial plasma concentrations for free fatty acid (FFA) and triacylglycerol (C16 to C18) were higher in late pregnancy than in early lactation in both types of crossbred animals. The values of AV difference and the net uptake by the mammary gland for FFA were variable during late pregnancy and lactating periods in all groups. There were no significant differences for AV difference, extraction ratio and net uptake of triacylglycerol during lactation advance in both groups of 50%HF and 87.5%HF animals feeding either hay or urea treated rice straw. These results suggest that the adaptations to either hay or urea treated rice straw by the mammary gland of crossbred HF animals allow for an adequate nutrient supply during pregnancy and lactation. There is no difference in the mode of mammary uptake of substrates in the same crossbred animals in response to feeding hay or urea treated rice straw. The differences in utilizing nutrients by the mammary gland for milk production between 87.5%HF and 50%HF animals would be dependent on changes in both intra-mammary factors and extra-mammary factors. (Asian-Aust. J. Anim. Sci. 2002. Vol 15, No. 10 : 1445-1452)

The effect of forage grinding and cutting height of urea treated whole crop wheat on the milk production and diet digestibility in dairy cows

It has previously been demonstrated that feeding urea treated whole crop wheat to dairy cows results in a significant increase in dry matter intake but has little effect on milk yield (Sutton et al, 1997). Part of the reason behind this lack of response has been attributed to a decrease in digestibility, particularly that of starch. A forage mill has recently been developed which allow the grains to be ground prior to ensiling and potentially increase their digestibility. An alternative way to increase the energy value of whole crop wheat is to increase cutting/stubble height. Work by Weller et al, (1995) demonstrated an increase in calculated ME from 10.6 to 11.2 MJ/kg DM by increasing stubble height from 10cm to 40cm. The objective of the current experiment was therefore to determine the effects of forage processing (grinding) and cutting height at harvest of urea-treated whole crop wheat on the intake, milk production and diet digestibility in dairy cows.

Effect of Feeding Urea and Acetic Acid Treated Wheat Straw on the Digestibility of Nutrients in Adult Male Murrah Buffaloes (Bubalus bubalis)

Effect of Feeding Urea and Acetic Acid Treated Wheat Straw on the Digestibility of Nutrients in Adult Male Murrah Buffaloes (Bubalus bubalis)

Evaluation of the Performance of Different Dairy Breeds Feeding Urea Treated Rice Straw Based Similar Diet

Evaluation of the Performance of Different Dairy Breeds Feeding Urea Treated Rice Straw Based Similar Diet

Improving rumen fermentation and milk production with legume-tree fodder in the tropics

Feeding leguminous fodder that is high in protein can improve rumen fermentation parameters leading to increased digestibility and intake of low quality fibrous feeds, and hence improved animal production. The effect on dry matter (DM) degradation and rumen fermentation parameters of feeding urea or tree legume foliage (Erythrina poeppigiana or Gliricidia sepium), as protein supplements to a basal diet of Hyparrhenia rufa hay, rice bran and molasses, was studied with rumen fistulated steers (Zebu × Creole crossbreeds). In a second experiment, Jersey × Creole crossbreeds were used to determine the effect of the above three treatments on milk production. Both experiments were conducted at CATIE's experimental farm, Turrialba, Costa Rica (9°58′ N; 83°31′ W; 639 m above sea level; mean annual precipitation of 2600 mm; mean daily temperature 22 °C). The disappearance of hay DM in the rumen increased with time to 144 hours and potential degradation of hay DM was significantly higher (P 0.05) when cows received either E. poeppigiana or G. sepium foliages as protein supplements (7.3 and 7.4 kg milk/cow/day, respectively) but they were superior (P < 0.05) to urea supplementation (6.7 kg milk/cow/day).

Bunch stalk feeding of urea in banana Musa (AAB group) ‘Nendran’

The influence of urea feeding at the cut bunch stalk end of the rachis of banana was studied in tissue culture plants of ‘Nendran’ banana having uniform sized bunches. A preliminary study for standardising the dose of urea showed the superiority of placing 30 g urea on two-week-old bunches. The main experiment on bunch stalk feeding, also revealed that placing 30 g urea on the cut stalk end at two weeks or at four weeks after complete emergence of the bunch resulted in maximum yield and other elite yield attributes. Bunch weight, finger weight, length and grade of ‘D’ finger and filling index are the yield parameters mostly affected by the bunch stalk feeding.

Effect of Feeding Urea Treated Rice and Wheat Straw on intake and Milk Yield of Lactating Buffaloes under Farmers Conditions

Effect of Feeding Urea Treated Rice and Wheat Straw on intake and Milk Yield of Lactating Buffaloes under Farmers Conditions

The effect of urea exposure on isoaspartyl content and protein l-isoaspartate methyltransferase activity in Drosophila melanogaster

Urea is a protein unfolding agent that can accumulate to locally high concentrations in tissues of many organisms. We used Drosophila melanogaster to test the hypothesis that urea loading would promote formation of isoaspartate (β-carboxyl-linked aspartate), a common form of protein damage that occurs most readily in unstructured polypeptides and flexible regions of folded proteins. Ten populations of flies were tested; five control populations of urea-sensitive flies and five previously selected urea-tolerant populations. We measured the effects of urea consumption on levels of both isoaspartate and protein l-isoaspartate methyltransferase (PIMT), an enzyme believed to function in the repair or removal of isoaspartyl proteins. For both sets of populations, urea feeding for 6 days increased isoaspartyl levels by approximately 60%, supporting the idea that disruption of protein secondary and tertiary structures can accelerate the formation of isoaspartate in vivo. Urea feeding tended to increase PIMT activity in both control and urea-tolerant populations. There were no significant differences in PIMT activities or isoaspartyl levels between the control and urea-tolerant flies raised on normal or urea food. The latter findings indicate that urea tolerance evolved in the selected populations without any significant change in PIMT expression or activity.

Influence of protein supplementation on reproductive traits of Awassi sheep grazing cereal stubble

Sheep in the dry areas of Iraq are heavily dependent on stubble grazing as their sole source of feed during mating season. However, as the grazing season progresses, both ewes and rams, exhaust the supply of nutritious parts and consequently the quality of the stubble and their nutritive value declines. To overcome this problem, urea feed blocks (UFB) were supplemented to sheep grazing stubble. This study was conducted to evaluate supplementation of UFB enriched with cotton seed meal as a source of undegradable protein on lambing, twinning and fertility of ewes as well as semen quality, sexual activity and some blood characteristics of rams. Fifty four mature ewes and eight rams were randomly divided into supplementated ewes (SE) and rams (SR) and control, non-supplemented ewes (NSE) and rams (NSR). Both SE and NSE animals were stubble grazed and SE offered UFB enriched with undegradable protein and AD 3E after their return from stubble. The NSR and SR were offered barley grain and straw and SR and SR fed in addition to UFB. Lambing and twinning rates were slightly higher and the percentage of barren ewes significantly lower in SE compared to NSE. Pen test parameters were not different between SR and NSR. On the other hand, sperm motility and concentration and percentage of dead and abnormal sperms were lower in SR. Supplementation had no effect on hemoglobin concentration, packed cell volume, red blood cells count but increased white blood cell count. The UFB enriched with undegradable protein had a positive effect on ewe fertility. In contrast, UFB reduced semen quality but did not influence sexual activity and most blood characteristics in rams.