Effects of the Dicarboxylic Acids Malate and Fumarate on E. coli O157:H7 and Salmonella enterica Typhimurium Populations in Pure Culture and in Mixed Ruminal Microorganism Fermentations

Abstract

The dicarboxylic acids malate and fumarate increase ruminal pH, reduce methane production, increase propionate and total volatile fatty acid (VFA) production, and reduce lactic acid accumulation in a manner similar to ionophores. These acids stimulate the ruminal bacterium Selenomonas ruminantium to ferment lactate to produce propionate. Thus, dicarboxylic acids have been suggested as nonantibiotic modifiers of the ruminal fermentation, but their impact on ruminal microbial ecology remains unknown. This study was designed to examine what effects these modifiers may have on intestinal pathogen populations such as Escherichia coli O157:H7 and S. enterica Typhimurium prior to their widespread incorporation into cattle rations. Pure cultures of E. coli O157:H7 strain 933 and S. enterica Typhimurium were grown with malate and fumarate added at 0, 1, 5, 10, and 20 mM (v/v; n = 3). Neither dicarboxylic acid inhibited (p > 0.1) the growth rate or final populations of E. coli O157:H7 or S. enterica Typhimurium. Ruminal fluid was collected from cattle (n = 2) and E. coli O157:H7 and S. enterica Typhimurium were added to separate ruminal fermentations incubated for 24 h at 39 degrees C. Fumarate and malate were added at concentrations of 0, 5, 10, and 20 mM (v/v; n = 2) and incubated for 24 h at 39 degrees C. Malate or fumarate addition did not affect (p > 0.1) populations of E. coli O157:H7 or S. enterica Typhimurium. However, the final pH was increased (p < 0.05), the acetate:propionate ratio was decreased (p < 0.05), and the total VFA production was increased (p < 0.05) by > or =10 mM dicarboxylic acid addition. These results confirm that dicarboxylic acids can modify ruminal fermentation, but they do not affect populations of critical foodborne pathogens.

Treatment of grain with organic acids at 2 different dietary phosphorus levels modulates ruminal microbial community structure and fermentation patterns in vitro

“…The potential of LAc treatment to enhance propionate formation has also been observed previously (Iqbal et al, 2009;Deckardt et al, 2015). It is possible that LAc treatment stimulated propionate formation by offering an electron sink for H 2 , leading to enhancement of the succinate-propionate pathway and the synthesis of propionate (Nisbet et al, 2009). On the other hand, although acetate is known as a main fermentation product of cellulolytic bacterial species (Christopherson et al, 2014), propionate and butyrate are produced by many bacterial groups using lactate, resistant starch, pectins, and hemicelluloses as substrates (Marounek and Dušková, 1999;Brouns et al, 2002;Duncan et al, 2004).…”

Effects of Flavonoids on Rumen Fermentation Activity, Methane Production, and Microbial Population

“…The ionophores such as monensin, lasalocid, and laidlomycin significantly suppressed the methane production in ruminants [3]. However, concerns including antibiotic resistance and detectable residual levels of these compounds in animal products limit the utilization of these additives [4]. In the case of probiotics, the commonly used microorganisms for ruminants are yeast and Aspergillus oryzae.…”

Use of dicarboxylic acids and polyphenols to attenuate reticular pH drop and acute phase response in dairy heifers fed a high grain diet

“…Good management and nutritional strategies alone [ 8 , 5 ] are not always enough to avoid the onset of SARA in high yielding dairy cows and for this reason other preventative measures have been suggested. This included physical manipulation of fiber and grain particle size [ 8 , 11 , 12 ], the inclusion of antibiotics in the diet [ 13 ], the use of yeasts and probiotic bacteria [ 14 , 15 ], and the addition of dicarboxylic acids [ 16 ], flavonoids [ 17 ] or essential oils [ 18 ] to manipulate rumen microbial communities and subsequently ruminal fermentation.…”