Endogenous fraction and urinary recovery of purine derivatives obtained by different methods in Nellore cattle1

Abstract

Two experiments were conducted to assess the endogenous fraction of purine derivative (PD) excretion, urinary recovery, and intestinal digestibility of purines in Nellore heifers. For both experiments, 8 Nellore heifers fitted with ruminal and abomasal cannulas were allocated to two 4 × 4 Latin squares. The diets were based on corn silage and concentrate (60 and 40% DM basis, respectively); feces and urine samples were obtained by total collection, and abomasal DM flow was estimated using indigestible NDF as an internal marker. In Exp. I, 4 of the 8 heifers (BW 258 ± 20 kg) were also fitted with ileal cannula. The planned treatments were 4 different DMI: 1.2, 1.6, 2.0, and 2.4% of BW (DM basis). The endogenous losses and purine recovery as urinary PD were estimated using linear regression between daily urinary PD excretion (Y) and daily abomasal flow of purine bases (X), expressed in millimoles per kilogram of BW(0.75). In Exp. II, the same 8 Nellore heifers (BW of 296 ± 15 kg) were fed at 1.37% BW (DM basis). The treatments were the infusion of purines (RNA from torula yeast, type VI, Sigma) into the abomasum in increasing amounts (0, 33, 66, and 100 mmol/d). All statistical analyses were performed using the PROC MIXED procedure in SAS. In Exp. I, the DMI range was 1.16 to 1.84% of BW and did not affect (P > 0.05) the apparent RNA digestibility in the small intestine, which had a mean of 75.6%, and a true digestibility of 93.0%. The mean ratio of the N-RNA to the total-N in the ruminal bacteria was 0.137. The daily urinary PD excretion (Y, mmol/kg of BW(0.75)) was a function of RNA flow in the abomasum (X, mmol/kg of BW(0.75)): Y = 0.860X + 0.460, where 0.860 and 0.460 were the PD recovery of purines and the endogenous fraction (in mmol/kg of BW(0.75)), respectively. In Exp. II, the daily urinary PD excretion was a function of RNA flow in the abomasum: Y = 0.741X + 0.301, where 0.741 and 0.301 were the recovery of PD in urine of infused purines and the endogenous losses (in mmol/kg of BW(0.75)), respectively. In conclusion, our data suggest that in Nellore heifers the respective values of endogenous PD excretion (mmol/kg of BW(0.75)), urinary recovery of the purines absorbed in the abomasum, and true digestibility of RNA in the small intestine were 0.30, 0.80, and 0.93.

Creatinine excretion and relationship with body weight of Nellore cattle

“…In addition to lactation, studies with cows had values that are also between the confidence interval obtained by this study: 23.41 mg/kg BW (Oliveira et al, 2001) and 24.04 and 24.07 mg/kg BW (Chizzotti et al, 2008). Since the diet of the animal is correctly balanced, the protein percentage decreases and the deposition of fat increases in empty body as the animal approaches the maturity weight.…”

“…This maturity weight is considered when the weight gain has little protein added (Reid et al, 1955). Considering growing animals, the creatinine excretion, expressed in mg/kg BW, alters due to variation in the percentage of muscle tissue in function of the body weight (Chizzotti et al, 2008).…”

“…The data of UCE were described by Pereira (2009), Barbosa et al (2006), Barbosa et al (2011) and Gionbelli (2010) (Table 1).…”

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).…”

Energy and protein requirements of crossbred Holstein x Zebu steers fed different levels of calcium and phosphorus in the diet

“…The absorbed purines (AP, mmol/d) were calculated from the PD excretion (PD, mmol/d) by using the following equation: where 0.80 is the recovery of absorbed purines as PD and 0.30 BW 0.75 is the endogenous purine excretion (BARBOSA et al, 2011).…”