Daily Purine Derivatives Excretion Research Articles

Effect of dietary Quebracho tannin extract on feed intake, digestibility, excretion of urinary purine derivatives and milk production in dairy cows

ABSTRACTThe aim of this study was to evaluate the effects of dietary Quebracho tannin extract (QTE) on feed intake, apparent total tract digestibility (ATTD), excretion of urinary purine derivatives (PD) and milk composition and yield in dairy cows. Fifty Holstein cows were divided into two groups. To reach a similar performance of both groups, cows were divided according to their milk yield, body weight, days in milk and number of lactations at the start of the experiment averaging 33.2 ± 8.2 kg/d, 637 ± 58 kg, 114 ± 73 d and 2.3 ± 1.6 lactations, respectively. The cows were fed a basal diet as total mixed ration containing on dry matter (DM) basis 34% grass silage, 32% maize silage and 34% concentrate feeds. Three dietary treatments were tested, the control (CON, basal diet without QTE), QTE15 (basal diet with QTE at 15 g/kg DM) and QTE30 (basal diet with QTE at 30 g/kg DM). Two treatments were arranged along six periods each 21 d (13 d adaptation phase and 8 d sampling phase). The ATTD of DM and organic matter were reduced only in Diet QTE30, whereas both QTE treatments reduced ATTD of fibre and nitrogen (N), indicating that QTE impaired rumen fermentation. Nevertheless, feed intake was unaffected by QTE. In Diet CON, urinary N excretion accounted for 29.8% of N intake and decreased in treatments QTE15 and QTE30 to 27.5% and 17.9%, respectively. Daily faecal N excretion increased in treatments CON, QTE15 and QTE30 from 211 to 237 and 273 g/d, respectively, which amounted to 39.0%, 42.4% and 51.7% of the N intake, respectively. Hence, QTE shifted N excretion from urine to faeces, whereas the proportion of ingested N appearing in milk was not affected by QTE (average 30.7% of N intake). Daily PD excretion as indicator for microbial crude protein (CP) flow at the duodenum decreased in treatment QTE30 compared with Diet CON from 413 to 280 mmol/d. The ratios of total PD to creatinine suggest that urinary PD excretion was already lower when feeding Diet QTE15. While there was no effect of Diet QTE15, treatment QTE30 reduced milk yield, milk fat and protein. Both QTE treatments reduced milk urea concentration, which suggest that ruminal degradation of dietary CP was reduced. In summary, adding QTE at dosages of 15 and 30 g/kg DM to diets of lactating dairy cows to improve feed and protein use efficiency is not recommended.

Endogenous fraction and urinary recovery of purine derivatives in Nellore and Holstein heifers with abomasal purine infusion

The excretion of purine derivatives (PD) as an index of microbial biomass production in the rumen can be biased by the endogenous fraction and the incomplete urinary recovery of absorbed purines. Moreover, several authors have suggested differences for endogenous fraction of purine derivatives between genetic groups. The objective of this study was to estimate the endogenous fraction of PD and the urinary recovery of purines in Nellore and Holstein heifers fed diets containing 60% corn silage and 40% concentrate daily (13g dry matter/kg body weight). Daily creatinine excretion, intake and digestibility of dry matter and nutrients were also evaluated. Four Nellore heifers and four Holstein heifers fistulated at the rumen and abomasum, body weight of 270±7.76 and 225±7.16kg, respectively, were allocated in two 4×4 Latin squares. The experimental treatments consisted of four doses of RNA infusion (Torula Yeast): 0, 33, 66, or 100mmol/day. The endogenous losses of PD and the recovery of purine bases were estimated using a regression of the daily excretion of PD (Ŷ) and the abomasal flow of purine bases (X). There was no difference (P>0.05) between the regression equations for PD excretion and daily abomasal flow of purines for each genetic group, resulting in the following regression: Ŷ=0.405+0.923X, where 0.405mmol/kg0.75 and 0.923 represent the endogenous fraction and the recovery of purine bases in the abomasum, respectively, for both genetic groups. The infusion and genetic groups did not affect (P>0.05) the daily creatinine excretion, which averaged 27.23mg/kg BW. We concluded that there are no differences between Nellore and Holstein heifers in the endogenous fraction of PD, the urinary recovery of purines, and creatinine excretion, with average values of 0.405mmol/kg0.75, 0.92, and 27.23mg/kg BW, respectively.

Renal and Salivary Excretions of Plasma Purine Derivatives in Swamp Buffaloes and Zebu Cattle

This study compared the recovery rate of intrajugular-administered allantoin in the urine and saliva between swamp buffaloes and zebu cattle to examine whether it could explain the lower excretion rate of urinary purine derivatives (PD) in the buffaloes. Three male swamp buffalo yearlings, with an average body weight of 349±40.35 kg, and three Thai native cattle (154±3.26 kg) of similar age and sex were used in the study. Animals were kept in individual pens and fed at a maintenance energy level with a diet containing 65% monk bean husk (Vigna radiata) as roughage and 35% concentrates. Allantoin solution was infused into the jugular vein in four incremental rates equivalent to 0, 5, 10 and 15 mmol/d and urine was collected daily in acidified form. Daily PD excretion was linearly correlated with intrajugular allantoin infusion in both species. The relationship between daily urinary PD excretion (Y, mmol/d) and intrajugular allantoin infused (X, mmol/d) was Y = 0.75±0.318X+22.45±2.98 (r2 = 0.36, n = 12, MSE = 38.02, CV = 21.9, p<0.01) for swamp buffaloes and Y = 0.96±0.10X+15. 93±0.92 (r2 = 0.91, n = 12, MSE = 3.60, CV = 8.27, p<0.01) for zebu cattle. The salivary PD concentration was not correlated with intrajugular allantoin infusion in both species, with values for buffaloes numerically lower than those for cattle. The present study reconfirmed previous studies that buffaloes have a lower plasma PD excretion rate via the renal route and a significant proportion (22%) of the plasma PD loss is via the saliva. However, results of our present and previous studies suggest that differences in purine base (PB) metabolism between buffaloes and zebu cattle occur before the purine compounds reach the plasma pool.

Determination of creatinine excretion and evaluation of spot urine sampling in Holstein cattle

Four experiments were carried out to determine urinary creatinine excretion in Holstein growing bulls, lactating cows, and replacement heifers. In addition, we evaluated the use of spot sampling technique to estimate purine derivatives (PD) excretion. In Experiment I, 15 lactating cows were used in a randomized block design to compare creatinine excretion obtained in different time-spans of urine collection (during 6, 9, 12, 15, 18, 21, and 24 h). In Experiment II, four bulls were allocated in a 4 × 4 Latin square to evaluate the effect of diet (levels of cottonseed hulls of 0, 10, 20, and 30% of the DM) on excretion of creatinine. In Experiment III, 15 lactating cows were used to evaluate the effect of milk production (ranging from 3.9 to 36.7 kg/d) on daily creatinine and PD excretions. In Experiment IV, 22 replacement heifers were utilized to evaluate the effect of body weight (BW, ranging from 107 to 545 kg) on daily creatinine and PD excretions. For all experiments, total urine collections were made over 24 h and daily creatinine and PD excretions were determined. Different time-spans for total urine collection had no effect ( P = 0.70) on creatinine excretion compared to the 24-h collection period, indicating a constant excretion rate of creatinine. The roughage source did not influence ( P = 0.64) creatinine excretion by bulls, averaging 0.248 ± 0.008 mmol/kg BW. Similarly, milk production did not affect ( P = 0.82) creatinine excretion in cows, averaging 0.212 ± 0.004 mmol/kg BW. In contrast, the creatinine excretion (mmol/kg BW) decreased linearly ( P < 0.001) as BW of heifers increased, suggesting that creatinine excretion might vary with the degree of maturity of growing animals. There were no differences (P > 0.14) between the 24-h total collection and spot sampling technique in estimating daily PD excretion. The spot sampling technique may be used to estimate the daily excretion of urinary PD in Holstein cattle under practical conditions.

The use of purine derivatives/creatinine ratio in spot urine samples as an index of microbial protein supply in Yerli Kara crossbred cattle

Three experiments were conducted to evaluate the use of purine derivatives (PD)/creatinine ratio in spot urine samples as an index of microbial protein supply in Yerli Kara crossbred cattle (YK-C). In Experiment I, response of daily PD excretion to feed intake in YK-C at state farm was measured. In Experiment II, spot urine sampling techniques was applied at state farm and four YK-C bulls were used. In Experiment III, spot urine sampling technique was applied at small-holder farms. There were significant correlations ( R 2 = 0.99) between PD excretion (mmol/day) and digestible organic matter intake (DOMI) (kg/day) in Experiment I, Y = 12.5 (± 0.5) + 19.7 (± 3.5) X ( R 2 = 0.99, n = 16). The equation obtained from Experiment I could be expressed as: Y = − 2.3 (± 0.3) + 0.953 (± 0.06) X, ( R 2 = 0.99, n = 49) where Y is PD excretion (mmol/day) and X is the PDC index. The PDC index was calculated as the molar concentration ratio of PD to creatinine times the metabolic body weight (kg). The corresponding microbial-N values to PDC index of groups I, II and III in developed banding system are 15–25 g/day. Experimentally estimated DOMI was 2.21 ± 0.15 kg/day. Estimated DOMI of groups I, II, and III were 2.8 ± 0.6, 2.6 ± 0.7 and 2.7 ± 0.7 kg/day, respectively. In conclusion, the PDC index in spot urine samples could be used under similar farm condition as an indicator of microbial protein supply in YK-C cattle. Estimated DOMI from PDC index in spot urine samples under defined field conditions may help the development of feeding strategies for YK-C cattle held by small holders.

Effect of dietary energy levels on the urinary excretion of purine derivatives in sheep

ABSTRACTThe effect of dietary energy levels on the urinary excretion of purine derivatives (PD) was investigated in sheep fed hay and concentrate diets. In addition, the possibility of using PD concentrations in spot samples of urine as a useful tool for determining daily PD excretion was also examined. Three female lambs (mean bodyweight (BW) ± standard error, 31.4 ± 1.0 kg) were fed three diets consisting of timothy hay (20 g dry matter/kg BW per day) and rolled barley at three different energy levels (low‐energy (LE), medium‐energy (ME) and high‐energy (HE) at 1.0‐, 1.2‐ and 1.5‐fold greater than the maintenance level of energy (450 KJ/BW0.75/day), respectively) in a 3 × 3 Latin square design. The dietary protein level was almost constant (380 mg nitrogen/BW0.75/day as digestible crude protein base) and was adjusted using soybean protein. Digestible organic matter intake (DOMI) increased (P &lt; 0.05) with an increase in the dietary energy level and there was a difference (P &lt; 0.05) in the organic matter digestibility between the LE and HE diets. For urinary PD excretion, the differences between the LE and ME diets and the HE diet were significant (P &lt; 0.05), although there was no clear difference between the LE and ME diets. There was a positive correlation (r = 0.47, P &lt; 0.05) between urinary PD excretion and DOMI. There was also a correlation (r = 0.59, P &lt; 0.05) between the urinary PD level at 7–8 h after the morning feed and the daily total PD excretion, suggesting that the PD level in spot urine samples could be useful for estimating microbial protein synthesized in the rumen and/or digested in the lower gut.

Balanço de compostos nitrogenados, produção de proteína microbiana e concentração plasmática de uréia em vacas leiteiras alimentadas com dietas à base de cana-de-açúcar

Doze vacas da raça Holandesa, puras e mestiças, foram distribuídas em três quadrados latinos 4 x 4, com o objetivo de avaliar o balanço de nitrogênio (N), a produção de proteína microbiana, a concentração de uréia no plasma e no leite e diferentes tempos de coleta de urina. As dietas foram constituídas à base de silagem de milho (SM) (AG 1051) com relação volumoso:concentrado (V:C) de 60:40, com base na matéria seca (MS), ou à base de cana-de-açúcar (CA) (RB 855536) com relação V:C de 60:40, com 0,35 ou 1% de uréia+sulfato de amônio (SA) ou V:C de 50:50 com 1% de uréia+SA. O balanço de N, para a dieta à base de SM, foi maior, 88 g N/dia, do que para as dietas com CA com 40% de concentrado, 67 ou 69 g N/dia. Entre as dietas contendo CA, não houve diferença no balanço de N. A excreção média diária total de derivados de purinas (DP), as purinas absorvidas (PA) e a estimativa de N microbiano, 221 g/dia, foram maiores para dieta à base de SM, quando comparada com as dietas à base de CA com 40% de concentrado, 180 ou 178 g N microbiano/dia. Entretanto, quando comparada à dieta contendo CA com 50% de concentrado, não houve diferença para as variáveis balanço de N, DP, PA e N microbiano. Não houve diferença na excreção média diária total de DP, PA e produção de N microbiano, entre as dietas contendo CA. Em relação aos tempos de coleta de urina de 24 ou 8 horas, ou seja, coleta total ou parcial, não houve diferença nas excreções médias diárias de creatinina (24 x 22 mg/kg de PV), uréia, alantoína (245 x 228 mmol/dia) e ácido úrico. A dieta contendo CA, corrigida com 1% de uréia+SA, com 50% de concentrado proporcionou produção de proteína microbiana semelhante à dieta à base de SM com relação V:C de 60:40, com base na MS. O N-uréia plasmático parece ser melhor indicador do metabolismo protéico em vacas leiteiras do que o N-uréia no leite.

Response of urinary and plasma purine derivatives to various rates and infusion patterns of purines in sheep nourished by intragastric infusion

The effects of exogenous purine supply on plasma concentration and urinary excretion of purine derivatives (PD), which include allantoin, uric acid, xanthine and hypoxanthine, were studied. Five sheep, totally nourished by intragastric infusion of volatile fatty acids and casein, were given an abomasal infusion of a mixture of adenosine and guanosine at three levels (5·0, 10·0 and 20·0 mmol/day) each in four infusion patterns (as one, two, or four 3-h infusion periods per day or infused continuously, P1 to P4 respectively). Urine was collected hourly over 24 h, and plasma samples were collected hourly for 7 h from the start of purine infusion. Both the plasma concentration of PD and its urinary excretion changed rapidly in response to the start and termination of purine infusion with a lag time of 2–3 h. Individual sheep differed considerably in the relative proportions of the different purine derivatives in the urine. The endogenous urinary PD excretion averaged 176 (±S.E. 28) μmol/kg W0·75 per day. Daily PD excretion in urine increased with the amount of purine infusion, but at each level the output decreased significantly in a gradient from P1 to P4. The response of total PD excretion (Y, mmol/day) to daily purine input (X, mmol/day) was predictable and followed the equation: Y=0·81 (±0·02)X+3·07(±0·81) × (u e−0·27X/u +1−u), where u is the duration over which the daily input was infused expressed as a proportion of 24 h. The recovery of the infused purines averaged 81%. When the infusion was given continuously, plasma PD concentration was relatively stable and was linearly correlated with the purine entry rate and daily PD excretion in the urine. The estimated glomerular filtration rate was 150 (±S.E. 16) litres/day and the estimated tubular transport maximum was 2·6 (±S.E. 1·3) mmol/day. It is concluded that due to the rapidity in the response of plasma and urinary PD to changes in the exogenous purine supply, spot measurements of PD in urine or plasma can be of no value for the estimation of exogenous purine uptake unless the purine supply is relatively constant throughout the day. Daily PD excretion in urine related to the exogenous purine uptake in a predictable and reproduceable manner and provides a reliable index for the estimation of the exogenous purine uptake.

Effect of Fasting on the Urinary Excretion of Nitrogen and Purine Derivatives by Zebu(Bos indicus)and Crossbred (Bos indicus x Bos taurus) Cattle

Abstract Osuji, P.O., Nsahlai I.V. and Khalili, H. 1996. Effect of fasting on the urinary excretion of nitrogen and purine derivatives by zebu (Bos indicus) and crossbred (Bos indicus x Bos taurus) cattle. J. Appl. Anim. Res., 10: 39–47. Six cattle [3 Boran (Bos indicus) and 3 crossbred (Bos indicus x Bos taurus)] were fasted for 20 days to estimate the effect of fasting on the excretion of nitrogen (N) and purine derivatives (PD) in the urine. PD excretion (y) for each genotype was related to time (t in days) by means of an exponential model: F=A+Be−kt where A is the endogenous excretion, k the fractional rate of excretion of exogenous PD B. The equations relating y to time (t) were: y = 0.172+0.178e−0.392t, R2 = 0.86; and y = 0.108 + 0.146e−0.108t R2 = 0.61 for the zebu and crossbred cattle, respectively. The daily fasting urinary nitrogen (N g/kg W0.75) was related to total daily PD excretion (y mmol/kg W0.75) by the equations: y = 0.00294 + 0.7285 ± 0.136 N, Adj R2 = 0.75 (crosses) y = 0.01099 + 0.922...

Evaluation of the use of the purine derivative: creatinine ratio in spot urine and plasma samples as an index of microbial protein supply in ruminants: studies in sheep

SUMMARYIn ruminants, the urinary excretion of purine derivatives (PD) reflects the absorption of microbial purines and can be used as an index of microbial protein supply. The objective of this study, carried out in Aberdeen, 1992, was to examine whether PD concentrations in spot urine or plasma samples vary diurnally during a given feeding regime and if they reflect differences in daily PD excretion induced by varying feed intake. Sixteen sheep were offered ad libitum one of four diets (fresh weight basis, the rest of each diet being minerals and vitamins): (1) 99·9% lucerne (pelleted); (2) 50% hay, 30% barley, 9% fishmeal and 10% molasses; (3) 72% straw, 7% molasses and 20% molassed sugarbeet pulp; and (4) 97% barley. Measurements were made for 1 week after a 2-week adaptation period. Urine was collected daily on days 1–4 and hourly on days 5–7. Hourly urine collection was achieved using a fraction collector. Plasma samples were collected hourly from 09·00 to 17·00 h on day 4. Feed intake varied considerably (347–1718 g DM/day) between diets and between animals. Daily excretion of PD (7·1–22·6 mmol/day) was linearly related to DM intake (r = 0·85, n = 16), and so was the microbial N supply (3·9–19·5 g N/day) estimated from daily PD excretion (r = 0·87). In hourly urine samples, the ratio of PD:creatinine concentrations showed no significant difference between sampling times, and was linearlycorrelated with the daily PD excretion (r = 0·92). Similarly, plasma PD concentration also showed little diurnal fluctuation. Glomerular filtration rate (GFR) increased with feed intake. Plasma PD was not well correlated with daily PD excretion in urine (r = 0·57). The tubular load of PD (plasma PD × GFR) was better correlated with the daily excretion (r = 0·80). It appears that when sheep are fed ad libitum, PD in spot urine may provide a practical indicator of microbial protein supply status.

Purine derivatives in spot urine samples and plasma of sheep: a possible index of microbial protein supply

In ruminants, daily urinary excretion of purine derivatives (PD) reflects the absorption of microbial purines and can be used as an index of microbial protein supply (Chen, Ørskov and Hovell, 1991). The application could be extended to farm conditions if measurements based on spot urine samples or plasma could serve as an alternative index. The objective of this study was to examine whether PD concentrations in spot urine or plasma samples vary diurnally during a given feeding regime and if they reflect differences in daily PD excretion induced by varying feed intake.

Effect of feeding frequency on diurnal variation in plasma and urinary purine derivatives in steers

AbstractThe diurnal changes in plasma concentration and urinary excretion of purine derivatives (PD) were examined in four steers given their food in either one or two meals daily in two 18-day periods. In period 1, two steers were fed once daily (at 08.00 h) and the other two twice daily (at 08.00 and 16.00 h). In period 2, the treatments were switched. In the last 4 days of each period, plasma samples were taken from 08.00 to 24.00 h at 2 to 3 h intervals, and daily urine was collected in several 4 to 8h periods. With once daily feeding, allantoin concentration in plasma varied from 090 to 1·07 of the daily mean and with twice daily feeding, from 0·97 to 1·05 of mean. The coefficient of variation (CV) for total variation was 0·14. In urine, the concentration and hourly excretion of PD varied with sampling times (P &lt; 0·05) but the ratio of PD to creatinine was relatively constant even for once-daily feeding (CV, 0·02 for measurements at different times). The CV for total variation in the ratio was 0·19. The results suggest that diurnal variation in plasma allantoin concentration and in the ratio of allantoin (or total PD) to creatinine are relatively small even for once daily feeding. It thus seems that these measurements in spot samples may be suitable for use as a simple index of microbial protein supply if they are correlated with the daily PD excretion. The results also indicate that measurements in samples of plasma and urine taken between 15.00 and 20.00 h tended to give a better representation of the daily mean.