In vitro gas production profile and the formation of end products from non‐ washable, insoluble washable and soluble washable fractions in some concentrate ingredients

Abstract

A procedure that mimics washing in the in situ incubation technique, combined with an in vitro gas and volatile fatty acids (VFAs) production technique, was used to verify the assumption that rumen degradation behaviour of material washed out of nylon bags is instantaneous and complete. In a 6 × 4 factorial arrangement of treatments with three replicates, fractions of maize, barley, milo, yellow peas, lupins (a mixture of white and spotted lupins) and round-seeded brown faba beans were subjected to an in vitro incubation technique. Fractions were whole (WHO), non-washable (NWF), insoluble washable (ISWF) and soluble washable (SWF). In a manually operated in vitro fermentation system, another 24 samples of the same substrates were fermented for VFA and ammonia analysis. Except in lupins, ISWF in the concentrate ingredients was very rich in starch. SWF was relatively rich in ash, crude protein, soluble sugars, and a residual unknown fraction but contained only a negligible quantity of starch. Thus, the fermentation characteristics of ISWF were more like WHO and NWF than SWF. Total gas production of SWF was considerably lower than the other fractions. A very rapidly degradable fraction was seen in the first phase of degradation of SWF. The pattern of fermentation end-product formation for SWF differed from that of the other fractions.  2007 Society of Chemical Industry Keywords: concentrate ingredients; feed fractionation; gas production technique; washable fraction INTRODUCTION High-producing dairy cows have a high requirement for energy supplied by nutrients that differ in nature. Nowadays, it has become common practice to divide energy for dairy cows into ketogenic, glucogenic and aminogenic energy. The ratio in which such nutrients are supplied to organs and tissues is highly influenced by microbial fermentation in the rumen. Although dynamic models to describe rumen fermentation and to predict the quantity and quality of the nutrients resulting from it have been developed,

In vitro gas production profiles and fermentation end‐products in processed peas, lupins and faba beans

“…46 This observation is in line with our findings in the current study. Indeed, the multiphasic manner of gas production observed with the fermentation of the SWF of peas and faba beans in a previous study 13 was not observed in the current study (data not shown).…”

“…The same tendency of increasing unknown residual fraction of the SWF was observed in E-and EP-treated barley. 13 It has been reported that soluble fibres increase after pelleting 40 and extrusion. 41 However, the authors believe that further experiments has to be carried out to bear out this theory.…”

“…13 The current study, therefore, was aimed at establishing the effects of expander processing alone or in combination with pelleting on the chemical composition, dry matter distribution, in vitro degradative behaviour and formation of fermentation end-products in some legume seeds (peas, lupins and faba beans) and their fractions (non-washable fraction, insoluble washable fraction and soluble washable fraction).…”

Protein Structures among Bio-Ethanol Co-Products and Its Relationships with Ruminal and Intestinal Availability of Protein in Dairy Cattle

“…For incubation times of 72 h, 36 h, 12 h, 6 h and 2 h, seven, six, five, four and two bags of each sample were randomly incubated in the rumen of each cow, respectively. Immediately after retrieval, all bags were placed in cold tap water to stop microbial fermentation and then washed manually five times in cold tap water followed by oven drying at 55 °C for 48 h. The 0 h incubation samples were washed by the procedure described by Azarfar et al [25] to fractionated washable fraction (W) into a truly washable soluble fraction (S) and a washable but insoluble fraction (WI). Since the WI was almost zero, for the purpose of modelling it was assumed that the W fraction equalled the S fraction.…”

Assessing protein availability of different bioethanol coproducts in dairy cattle

“…For the incubation times of 72, 36, 12, 6 and 2 h, seven, six, five, four and two bags of each sample were incubated in the rumen of each cow, respectively. Immediately after retrieval, all bags were placed in cold tap water to stop the microbial fermentation and then washed manually five times in cold tap water followed by oven drying at 558C for 48 h. The 0 h incubation samples were washed by the procedure described by Azarfar et al (2007) to fractionate the washout fraction (W) into a water soluble fraction (S) and an insoluble fraction (WI). As the WI was almost zero, for the purpose of modeling it was assumed that the W fraction was equal to the S fraction.…”