The effect of replacing corn with glycerol on ruminal bacteria in continuous culture fermenters

Abstract

The effects of substituting corn with glycerol on DNA concentration of selected ruminal bacteria were investigated using continuous fermenters. Four continuous culture fermenters were used in a 4 × 4 Latin Square design with four 10 days consecutive periods. Treatment diets (60:40 forage to concentrate) were fed at 45 g/day dry matter (DM) in three equal portions. Glycerol (0.995 g/g glycerol) was used to replace corn in a grain mix at proportions of 0% (T0; control), 15% (T15), 30% (T30) and 45% (T45). On day 10 of each period, samples were collected from each fermenter 3 h after the morning feeding and analysed for volatile fatty acid and bacterial DNA concentration. Glycerol substitution was related to significantly higher butyrate, valerate and isovalerate concentrations. Compared with the T0 diet, acetate concentration was significantly lower with the T30 and T45 diets whilst propionate concentration was higher only with the T45 diet. The DNA concentrations for Butyrivibrio fibrisolvens and Selenomonas ruminantium decreased with the T30 and T45 diets compared with the T0 diet. No differences in the DNA concentrations for Ruminococcus albus and Succinivibrio dextrinosolvens amongst diets were observed. The findings show that substituting 15% of the dietary corn with glycerol had no substantive effects on fermentation processing or ruminal bacteria. Higher substitution levels, however, may adversely affect ruminal bacteria and negatively impact acetate production.

Actinomyces Ruminicola G10 - The Rumen Bacterium Recovered from Glycerol Enriched Cultivation Media

“…lactilytica (HOBSON and MANN, 1961). ABU et al, (2011) showed that glycerol substitution had no effects on pH, ammonia nitrogen concentration, and dry matter digestibility in vitro fermentations using cow rumen fluid as an inoculum. The numbers of Butyrivibrio fibrisolvens, Clostridium proteoclasticum, and S. ruminantium decreased under high level glycerol concentration diet but no differences for Ruminococcus albus and Succinivibrio dextrinosolvens among diets with different glycerol concentrations were observed.…”

Crude glycerin levels in pearl millet-based diets for Nellore young bulls in feedlot

“…However, while glycerin can increase the digestibility of diets because of its higher digestibility, its inclusion causes a reduction of the digestibility of the fiber fraction of diets because of the negative impact on the population of rumen fibrolytic bacteria (Abo El-Nor et al, 2010;Abughazaleh et al, 2011). In this study, it is believed that the positive and negative aspects of crude glycerin on the apparent digestibility of diets were offset, resulting in no effect of crude glycerin levels on the digestibility coefficients of dry matter, crude protein, ether extract, and total digestible nutrients of the diets.…”

Effect of glycerol in combination with alfalfa on in vitro gas production and microbial protein synthesis

“…Recent research involving glycerol has focused on using glycerol as a replacement for barley (Avila et al 2011;Harzia et al 2013) and/or corn (Donkin et al 2009;AbuGhazaleh et al 2011) in ruminant diets to reduce costs. However, there is evidence that glycerol is a glucogenic source (Johnson 1954;Re´mond et al 1993 (1 ) (National Research Council 2001;DeFrain et al 2004).…”

“…Although positive effects of glycerol (70, 140, or 210 g kg (1 DM) on NDF digestibility have been reported (Avila et al 2011;Meale et al 2013), some in vitro studies (Roger et al 1992;Abo El-Nor et al 2010) show an inhibitory cellulolytic effect of glycerol when added at 5, 7.2, or 10.8% of DM. Nevertheless, the mechanisms by which glycerol inhibits cellulolytic bacteria are still not clear (AbuGhazaleh et al 2011;Edwards et al 2012), although it is evident that glycerol affects adhesion and growth of rumen microorganisms (Roger et al 1992).…”

“…According to the US Energy Information Administration (US Energy Information Administration 2013), between 2005 and 2011, biodiesel production increased rapidly worldwide (from 71 to 403 millions of barrels per day), leading to an oversupply of glycerol. As a result, animal nutritionists are exploring new applications for glycerol, including: (1) as a feed additive to prevent ketosis in dairy cattle (DeFrain et al 2004), (2) as a substitute for conventional energy sources in livestock diets (Donkin et al 2009;AbuGhazaleh et al 2011), and (3) to modulate the biohydrogenation of lipids in order to incorporate unsaturated fats into ruminantproduced milk and meat (Krueger et al 2010;Edwards et al 2012).…”