The detection of possible sensor histidine kinases regulating citrate/malate metabolism from the bovine rumen microbial ecosystem

Abstract

Aims: To detect sensor histidine protein kinases (HPKs) similar to accessory gene regulator C (AgrC) from the rumen microbial ecosystem. Methods and the Results: Genes related to sensor HPKs were amplified by PCR using two pairs of agrC‐specfic primers from DNA extracted from bovine rumen contents. The PCR products were cloned, sequenced and phylogenetically analysed. It appeared that two sequences were HPKs. Conclusions: Although amino acid sequences deduced from the nucleotide sequences obtained in this study showed high similarities with sensor HPKs responding to citrate or C4‐dicarboxylates, they did not show high similarities with AgrC. Significance and Impact of the Study: This study revealed the presence in the rumen of sensor HPKs responding to citrate or C4‐dicarboxylates, which could stimulate rumen fermentation. Therefore, it has been shown that citrate or C4‐dicarboxylate metabolism is partially regulated by a two‐component regulatory system in some rumen bacteria.

Effects of addition of malic or citric acids on fermentation quality and chemical characteristics of alfalfa silage

“…Feeding trials also confirmed that malic acid had a positive effect on increasing milk production in dairy cows (Sniffen et al, 2006;Devant et al, 2007;Wang et al, 2009b) and improving beef cattle performance (Martin et al, 1999;Castillo et al, 2007). Citric acid is another essential intermediate in the citric acid cycle, which has a similar function in stimulating rumen fermentation and improving animal performance (Packett and Butcher, 1963;Sun et al, 2008;Wang et al, 2009a).…”

Effects of citric acid supplementation on rumen fermentation, urinary excretion of purine derivatives and feed digestibility in steers

“…Increase of acetate production in the rumen would increase the amount of energy to the ruminant. Furthermore, citrate can stimulate rumen fermentation 13. It is suggested that small amounts of CA may have a catalytic effect on rumen microbial metabolism.…”

“…It is suggested that small amounts of CA may have a catalytic effect on rumen microbial metabolism. Altering microbial metabolism offers a potential means of increasing feed efficiency 13. In fact, Packett and Butcher14 reported that the addition of sodium citrate at 2% to wether lamb diet resulted in a 47% increase in gain over the 86‐day feeding period and efficiency of utilization of feed was increased 23%.…”