Accuracy of the estimates of ammonia concentration in rumen fluid using different analytical methods
| Autor: | N.K.P. Souza, E. Detmann, S.C. Valadares Filho, V.A.C. Costa, D.S. Pina, D.I. Gomes, A.C. Queiroz, H.C. Mantovani |
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| Jazyk: | English<br />Portuguese |
| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Arquivo Brasileiro de Medicina Veterinária e Zootecnia, Vol 65, Iss 6, Pp 1752-1758 (2013) |
| Druh dokumentu: | article |
| ISSN: | 1678-4162 0102-0935 |
| DOI: | 10.1590/S0102-09352013000600024 |
| Popis: | The accuracy of two different methods in measuring the ammonia nitrogen (N-NH3) concentration in rumen fluid were evaluated: a catalyzed indophenol colorimetric reaction (CICR) and the Kjeldahl distillation (KD). Five buffered standard solutions containing volatile fatty acids, true protein, and known ammonia concentrations (0, 3, 6, 12, and 24 N-NH3 mg/dL) were used to simulate rumen fluid. Different ratios (10:1, 7.5:1, 5:1, 2.5:1, 1:1, 1:2.5, 1:5, 1:7.5, and 1:10) of a potassium hydroxide solution (KOH, 2 mol/L) to standard solutions were evaluated by the KD method. The accuracy of each method was evaluated by adjusting a simple linear regression model of the estimated N-NH3 concentrations on the N-NH3 concentrations in the standard solutions. When the KD method was used, N-NH3 was observed to be released from the deamination of true protein (P0.05). The estimates of the N-NH3 concentration obtained by the CICR method were found to be accurate (P>0.05). After the accuracy evaluation, ninety-three samples of rumen fluid were evaluated by the CICR and KD methods (using the 5:1 ratio of KOH solution to rumen fluid sample), assuming that the CICR estimates would be accurate. The N-NH3 concentrations obtained by the two methods were observed to be different (P |
| Databáze: | Directory of Open Access Journals |
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