Digestibility determinate by indirect method using C35 n-alkane

[摘要] - An experiment was conducted, on extraction and analysis of n-alkanes, to investigate the use of n-alkane (C35) present in forages as an internal marker for the digestibility determination. Samples of forages and feces were taken from conventional digestibility trials, which were previous conducted from 1978 to 1982. The C35 underestimated the dry matter and organic matter digestibilities, presenting an average difference in relation to in vivo of 4.68 (± 0.69) and 4,43 (± 0.85) perceptual units, respectively. The coefficient of regression did not differ from the unit, indicating that both methods were equivalent, having, however, the necessity of a correction factor. The coefficients of correlation observed for the dry and organic matter between the two methods were 0.87 and 0.85, respectively. The average fecal recovery of C35 was 91.76% (± 7.94), and this contributed to the bias of the method.

[学科分类] 兽医学

[关键词] gas chromatography;digestibility;tropical grasses;hydrocarbons;markers     IntroduçãoA cera das plantas possui em sua composição hidrocarbonetos alifáticos saturados (n-alcanos);com comprimentos da cadeia de carbono variando de C18 a C37;havendo predominância dos de cadeia ímpar sobre os pares (CHIBNALL et al