COMPARlSON OF SHORT AND LONG WAVELENGTH OF NEAR INFRARED SPECTROSCOPY FOR PREDICTING NITROGEN AND ALLAKTOIN IN URINE

ABSTRACT Total 130 urine samples collected from d.J.iry on[e were studied for knowing the possibility and accuracy of the use of long and short wavelength of near infrared spectroscopy (NIRS) for nitrogen and allantoin content in urine. The sJ.mples were randomly separated for the calibration (n=9~) and the validation samples (n=36). Short and long wavelength of NIRS was selected in the range of 700-1350 and 1350-2500 run, respectively. Four wavelengths selected from short wavelength were found mainly related to the N-H, C-H or O-H structure in both for nitrogen at 1225, 970, 1060 and 806 run and for all.wtoin at 990, 1030, 1170 and 815 run, respectively. M~while, the selection in long w:lvelcngth was found rn:l.inly related to the N-H bound or protein for e;:lch component at 1430, 1530, 2242 and 1960 run for nitrogen and 2180, 2242, 1978 and 1530 run for allantoin, respectively. CoeffiCient correlation (and standard error) of prediction \\ith calibration equations using short wavelength were 0.85 (0.19), and 0.85 (47.7) for nitrogen and allantoin, respectively. Those values obwined from long wavelength were found to be 0.91 (0.13) and 0.92 (42.3), respectively. Judgement of validation ",ith RPD values (the ratio of stand:Hd deviation of reference data in prediction sJ.mple to the standard error of prediction by r\IR) for nitrogen and allantoin predicted by short wavelength were found 2.06 and 2.42, respectively. These values were lower than 2.5 the limit value recommended available for application. However, the use of long wavelength of r\IRS showed an possibility to predict nitrogen and allantoin in urine as shO\\TI by high RPD values to be 2.94 and 2.70, respectively. Key words: Near infrared, AIIJr,toin, Urine

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Dietary manipulation is one promising approach to reducing methane (CH4) emissions from forage-fed ruminants. Studies were conducted to evaluate the effects of feeding two concentrations of tannins from Mimosa spp. on rumen fermentation, methanogenesis and energy partitioning in goats. Adult male goats were used in three trials where three diets with increasing concentrations of tannins (control, low-tannin and high-tannin) were fed in a switch-over design. The control diet consisted of 0·65 timothy hay, 0·20 crushed maize and 0·15 soybean meal; low- and high-tannin diets contained 0·975 and 0·950 of the control diet, respectively, mixed with 0·025 and 0·050 of a commercial compound containing tannins with mean crude protein (CP) of 147 g/kg dry matter (DM) and gross energy (GE) 19 MJ/kg DM, respectively. Total contents (DM basis) of tannins (hydrolysable and condensed) in the control, low- and high-tannin diets were 0, 2·8 and 5·6 g/kg DM, respectively. The tannin source contained 37 and 76 g/kg DM of condensed and hydrolysable tannins, respectively (DM basis). The DM (664 g/d) and GE intakes (19·0 MJ/d) were similar among diet groups. Digestibilities of all dietary components in the high-tannin diet were lower (P < 0·05) than low-tannin and control diets. The faecal energy (MJ/d) output was lowest in the control diet (3·49) and increased (P < 0·05) in tannin-fed goats (3·80; 4·87) resulting in a corresponding decrease in digestible energy (DE). Methane emission, expressed both on absolute and per unit of feed intake basis, decreased (P < 0·05) with increasing concentration of tannins in the diet. For example, CH4 energy excretion was 0·98, 0·87 and 0·76 MJ/d for goats on control, low- and high-tannin diets, respectively, whereas their corresponding values for CH4 conversion ratio were 0·079, 0·069 and 0·060 of GE intake. These results suggest that natural tannins, even at a low concentration (2·8 g/kg DM of the diet), reduce CH4 emissions, and tree leaves containing appreciable amounts of tannins may potentially be exploited as natural feed additives in ruminants.Not Availabl

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