Influence of Level of Feed Intake on Concentration of Purine Derivatives in Urinary Spot Samples and Microbial Nitrogen Supply in Crossbred Bulls

Abstract

The potential of the spot urine sampling technique as an alternative to performing a total urine collection to predict the microbial nitrogen supply was evaluated in crossbred bulls. In a completely randomized design, 20 growing crossbred bulls were assigned four levels of feed intake (120, 100, 80 and 60% of voluntary dry matter intake) on diets comprised of wheat straw and concentrate mixture (50:50). After three months of experimental feeding, a metabolism trial was conducted for ten days, during which spot urine collections were performed every 6 h post feeding on days 9 and 10. The daily urinary excretion of allantoin (A) and purine derivatives (PD) decreased with the reduction in feed intake while creatinine (C) excretion remained similar in animals fed at different levels. The microbial nitrogen (MN) supply calculated from the PD excreted in total urine (35.08 to 72.08 g/d) was higher at increased levels of feed intake. PD concentration in spot urine samples had poor correlation with feed intake except at 12 h post feeding. A/C ratio and PD/C ratio in spot urine samples remained similar irrespective of sampling time and significantly (p<0.01) correlated with daily urinary PD excretion, digestible organic matter intake and dry matter (DM) intake. However, no significant differences were evident in these ratios among animals fed at levels 120, 100 and 80% of voluntary dry matter intake (VDMI) at different times post feeding. These results suggests that the spot urine sampling technique to predict the microbial protein supply is not suitable for detecting small differences in MN supply and hence, estimation of PD excreted in total urine (mmol/d) is necessary to assess precisely the MN supply in crossbred bulls.

Urinary excretion of purine derivatives as influenced by GFR and plasma retention of purines in cattle (<i>Bos indicus</i> × <i>Bos taurus</i>) and buffalo (<i>Bubalus bubalis</i>) bulls

“…The present values were lower, however, than those reported earlier for the same two species by Dipu et al (2006) and George et al (2006); this may be due to the lower DOMI and body weights of experimental animals in the present experiment. Hall et al (2004) deduced that it is also conceptually sound to assume that animal performance will largely depend upon the amount of DOMI, hence the use of PD excretion to predict DOMI would be the most appropriate.…”

Urinary creatinine as a nutritional and urinary volume marker in sheep fed with tropical or temperate forages

“…Reference values for sheep (0.46 to 0.52mmol/kg LW 0,75 ) described by for daily excretion of creatinine per unit of metabolic weight are well above those found in this study. However, differences between breeds and species are conceivable, mainly due to variations in body weight and proportion of muscle mass (George et al, 2006), suggesting the need for caution in generalizing the values.…”

Estimasi Sintesis Protein Mikrobia Rumen Menggunakan Ekskresi Derivat Purin dalam Urin dengan Teknik Spot Sampling pada Kambing Bligon dan Kambing Kejobong

“…Mereka meneliti ekskresi DP kambing. Barbosa et al (2011) dan Braga et al (2012) meneliti ekskresi DP pada sapi Nellore, kemudian George et al (2006) dan Singh et al (2007) meneliti ekskresi DP pada sapi crossbred, sedangkan Chizzotti et al (2008) dan Kazemi-Bonchenari et al (2011) (Prawirodigdo et al, 2008) dan Blora (Utomo et al, 2005). Kambing Kejobong diduga merupakan persilangan kambing Kacang dengan Benggala yang diseleksi secara turun temurun di daerah Purbalingga Jawa Tengah, sehingga menghasilkan keseragaman warna tubuh hitam (Astuti et al, 2007).…”

“…Di sisi lain, kadar creatinine dalam urin tidak dipengaruhi oleh pakan yang dikonsumsi, melainkan dipengaruhi oleh berat badan ternak (Kertz et al, 1970;George et al, 2006). Mengingat hal tersebut, dapat dipahami bahwa kadar creatinine kedua bangsa kambing menunjukkan kesamaan, disebabkan kedua bangsa kambing yang digunakan pada penelitian ini memiliki rentang berat badan yang homogen.…”

“…Apabila dikaji lebih mendalam, akan lebih lengkap jika rentang waktu spot sampling dikaitkan dengan waktu pemberian pakan. Hal ini mengingat pendapat Chen et al (1992) dan George et al (2006) yang menyatakan bahwa terdapat variasi konsentrasi DP dalam satu hari. Variasi konsentrasi DP ini dapat disebabkan karena variasi diurnal absorbsi purin mikrobia pada usus yang disebabkan frekuensi makan ternak, sehingga akan lebih baik apabila waktu spot sampling juga diperhitungkan berdasarkan waktu pemberian pakan.…”