Effect of Dietary Concentrate:forage Ratios and Undegraded Dietary Protein on Nitrogen Balance and Urinary Excretion of Purine Derivatives in Dorperxthin-tailed Han Crossbred Lambs

文献类型： 外文期刊

第一作者： Ma, Tao

作者： Ma, Tao;Tu, Yan;Jiang, Cheng-gang;Zhang, Nai-feng;Li, Yan-ling;Si, Bing-wen;Lou, Can;Diao, Qi-yu;Deng, Kai-dong

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期刊名称：ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES （ 影响因子：2.509； 五年影响因子：2.604 ）

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收录情况： SCI

摘要： This study aimed to investigate dietary concentrate:forage ratios (C:F) and undegraded dietary protein (UDP) on nitrogen balance and urinary excretion of purine derivatives (PD) in lambs. Four Dorperxthin-tailed Han crossbred castrated lambs with 62.3+/-1.9 kg body weight at 10 months of age were randomly assigned to four dietary treatments in a 2x2 factorial arrangement of two levels of C:F (40:60 and 60:40) and two levels of UDP (35% and 50% of CP), according to a complete 4x4 Latin-square design. Each experimental period lasted for 19 d. After a 7-d adaptation period, lambs were moved into individual metabolism crateS for 12 d including 7 d of adaption and 5 d of metabolism trial. During the metabolism trial, total urine was collected for 24 h and spot urine samples were also collected at different times. Urinary PD was measured using a colorimetric method and creatinine was measured using an automated analyzer. Intake of dry matter (DM) (p<0.01) and organic matter (OM) (p<0.01) increased as the level of UDP decreased. Fecal N was not affected by dietary treatment (p>0.05) while urinary N increased as the level of UDP decreased (p<0.05), but decreased as dietary C:F increased (p<0.05). Nitrogen retention increased as dietary C:F increased (p<0.05). As dietary C:F increased, urinary excretion of PD increased (p<0.05), but was not affected by dietary UDP (p>0.05) or interaction between dietary treatments (p>0.05). Daily excretion of creatinine was not affected by dietary treatments (p<0.05), with an average value of 0.334+/-0.005 mmol/kg BW0.75. A linear correlation was found between total PD excretion and PDC index (R-2 = 0.93). Concentrations of creatinine and PDC index in spot urine were unaffected by sampling time (p>0.05) and a good correlation was found between the PDC index (average value of three times) of spot urine and daily excretion of PD (R-2 = 0.88). These results suggest that for animals fed ad libitum, the PDC index in spot urine is effective to predict daily excretion of PD. In order to improve the accuracy of the spot sampling technique, an appropriate lag phase between the time of feeding and sampling should be determined so that the sampling time can coincide with the peak concentration of PD in the urine.RI TU, YAN/C-3378-2014OI TU, YAN/0000-0002-4324-6188

分类号： Q95

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