Comparison of in vitro gas production technique with in situ nylon bag technique to estimate dry matter degradation

Abstract

Dry matter (DM) degradation of wheat straw (WS), barley straw (BS), lucerne hay (LH) and maize silage (MS) was determined using two different techniques: (i) in vitro gas production and (ii) nylon bag degradability technique. In vitro gas production and in situ DM disappearance were measured after 3, 6, 12, 24, 48, 72 and 96 hours of incubation. In situ and in vitro DM degradation kinetics was described using the equation y = a + b (1 -e ct ). In all incubations there were significant (P < 0.001) correlations between gas production and in situ DM disappearance or estimated parameters ((a + b) gas and (a + b) is or (a + b) gas and EDMD is ) whereas there were no significant (P > 0.05) correlations between c gas and c is or b gas and b is . Gas production from the insoluble fraction (b) alone explained 98.3% of the variation of EDMD. The inclusion of gas production from the quickly soluble fraction (a) and rate constant (c) of gas production in the regression equation improved the accuracy of EDMD prediction. The correlations between the results of both methodologies seem to be sufficiently strong to predict degradability parameters from gas production parameters. It was concluded that the in vitro gas production technique has good potentiality to predict in situ DM disappearance and some DM degradation parameters.Keywords: in vitro gas production; in situ dry matter degradability; forage 61Czech J. Anim. Sci., 50, 2005 (2): 60-67 Original Paper et al., 1999Cone et al., 1999Cone et al., , 1998Cone et al., , 2002. However, the information available can be considered limited and results somewhat inconsistent. The aim of this study was (I) to determine fermentation kinetics using in vitro gas production and the in situ nylon bag technique and (II) to evaluate the correlations between the fermentation kinetics obtained by two different techniques. MATERIAL AND METHODS Forages and chemical analysisCommercially available and widely used four forages consisting of wheat straw, barley straw, lucerne hay and maize silage were used in this experiment. After drying forage samples were milled through a 1-mm sieve for chemical analysis. DM was determined by drying the samples at 105°C overnight and ashing the samples in a muffle furnace at 525°C for 8 h. Nitrogen (N) content was measured by the Kjeldahl method (AOAC, 1990). Crude protein was calculated as N × 6.25. Neutral detergent fibre (NDF) and acid detergent fibre (ADF) contents were determined by the method of AOAC (1990). Starch content was determined by the method according to MacRea and Armstrong (1968). In vitro gas productionForage samples milled through a 1-mm sieve were incubated in vitro in rumen fluid in calibrated glass syringes following the procedures of Menke and Steingass (1988). Rumen fluid was obtained from three fistulated sheep fed twice daily with a diet containing lucerne hay (60%) and concentrate (40%). Digestion medium was prepared mixing 500 ml of distilled water, 0.1 ml micro-mineral solution, 200 ml buffer solution, 200 ml macro-mi...

Determining Nutritive Value of Cereal Crop Residues and Lentil (&lt;i&gt;Lens esculanta&lt;/i&gt;) Straw for Ruminants

“…Besides, the potentially degradable (a + b), and c fraction as well as the ED at 0.02 and 0.05 passage rates of DM for WS were identical to those reported in [30]. However, the value of a fraction of DM for WS is lower and that of b higher in the studies of [31] and [30] than in the current study. The OM a fraction for WS is similar to that reported by [30] while b, c fraction and ED are lower in the present study.…”

“…The values of b fraction and ED of DM for BS are different from those reported by [31] and [30]. The OM a, b fractions and ED for BS are lower than those reported by [30].…”

Anaerobic degradability of organic matter of cattle faeces and a possibility of its utilization

“…Anaerobic degradability of organic matter of cattle faeces and a possibility of its utilization 2005a,b), degradation of feed organic matter by in vitro and in situ nylon-bag methods with measurement of gas production and description of the process kinetics (Kamalak et al, 2005). Degradability of organic matter in other disciplines is investigated particularly from the aspect of resistance in acid hydrolysis (Rovira and Vallejo, 2002;Shirato and Yokozava, 2006) or in oxidation (Blair et al, 1995;Chan et al, 2001).…”

Ruminal degradability of dry matter and neutral detergent fibre of grasses

“…However, there is a lack of information about ruminal degradability of dry matter (DM) and neutral detergent fibre (NDF) of the most important grass species grown in European countries. The rate and extent of DM fermentation in the rumen are crucial determinants of the nutrients utilized by ruminants (Kamalak et al, 2005). The main factor influencing the rate of fermentation of feeds is the structure of the carbohydrate fraction, especially the extent of lignification of the cell wall (Nagadi et al, 2000).…”