Avaliação do vício de "tempo longo" de indicadores internos em ensaio de digestão com ruminantes

Abstract

RESUMORealizou-se um ensaio de digestão com 20 ovinos machos, castrados, para avaliar o viés de "tempo longo" (VTL) dos indicadores internos: matéria seca indigestível (MSi) e fibra em detergente neutro (FDNi) e ácido (FDAi) indigestíveis. O experimento, com duração de 19 dias, foi implementado em delineamento em blocos completos casualizados, com cinco tratamentos (rações concentradas) e quatro blocos. As dietas utilizadas, formuladas para serem isoprotéicas (10% de proteína bruta), apresentaram 60% de feno de capim-coastcross e 40% de concentrado, constituído por milho grão, farelo de soja e casca de café, em diferentes proporções: 0; 6,25; 12,5; 18,75; e 25%. A concentração dos indicadores foi estimada em amostras de alimentos, sobras e fezes, por procedimento de incubação ruminal in situ, durante 144 horas. A relação entre consumo e excreção dos indicadores foi realizada pelo ajustamento de modelo de regressão linear simples, de forma independente dos efeitos fixos de tratamentos e blocos. Verificou-se recuperação completa dos indicadores MSi e FDNi (P>0,30), o que indica ausência de VTL. Observou-se VTL de +25,45 g/dia para a FDAi (P<0,06).Palavras-chave: fibra em detergente ácido indigestível, fibra em detergente neutro indigestível, matéria seca indigestível (0, 6.25, 12.5, 18.75, and 25%) ABSTRACT Long term bias (LTB) of internal markers indigestible dry matter (iDM), and indigestible neutral (iNDF) and acid (iADF) detergent fiber in a digestion

Inclusion of copaiba oil (Copaifera sp.) as additive in supplements for cattle on pasture

“…However, all levels of inclusion of copaiba oil in the diet provided a decline in production between 4 and 6 hours, decreasing to the 8-hour interval, except for diet 3 (1.0 g/kg/DM) that maintained production with a slight increase. The mean concentrations of NAR obtained in the ruminal fluid of the diets were close to the minimum recommended by Detmann et al (2007) for the maximum microbial growth and ruminal digestion, of 10 mg/dL, thus occurring the suitability of the growth medium to the availability of nitrogen compounds for microbial anabolism. According to Mehrez et al (1977), in order to reach the maximum microbial synthesis and potentiate the dry matter intake, the concentration of 23 mg NH 3 -N/100 mL is recommended.…”

“…For NAR, there was a difference between the supplement levels that were influenced by time, according to Figure 2. The mean value for NAR was 12.92 mg/dL; close to the minimum values required for maximum microbial growth and ruminal digestion, which is 10 mg/dL, as described by Detmann et al (2007), in order to increase the suitability of the growth medium to the availability of nitrogen compounds for microbial anabolism.…”

<b>Estimates of <i>in situ</i> digestibility and fibrous compounds in feeds for ruminants

“…Rates may actually been directly related to incubation time. According to Detmann et al (2007), different materials may require different protocols to estimate the indigestible fraction of DM, NDF and ADF. Casali et al (2008) later confirmed the great variability of critical periods between indexes and food, from 87.8h (iDM in wheat meal) to 268.6h (iNDF for corn silage with a 3 mm-size particle).…”

Fecal excretion patterns and short term bias of internal and external markers in a digestion assay with cattle

“…The long term bias, also called recovering bias, is associated with the capacity of a marker to be totally recovered in feces (Langlands et al, 1963, Detmann et al, 2007a. This is supposed to be an inherent characteristic of the marker.…”