Submitted to: Anaerobe
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/22/2005
Publication Date: 1/24/2006
Citation: Saengkerdsub, S., Woo-Kyun, K., Anderson, R.C., Nisbet, D.J., Ricke, S.C. 2006. Effects of nitrocompounds and feedstuffs on in vitro methane production in chicken cecal contents and rumen fluid. Anaerobe. 12:85-92. Interpretive Summary: Bacteria within the gut of animals help digest feedstuffs to a variety of products such as certain fatty acid compounds and methane gas (a waste product). The fatty acids are thought to be beneficial products of digestion whereas methane is thought to be a loss in dietary energy. The objective of this study was to examine if certain chemicals called nitrocompounds could reduce methane production by gut microorganisms harvested from sheep, cattle and chickens without adversely affecting production of the beneficial fatty acids. These nitrocompounds had been shown in earlier experiments to inhibit certain undesired foodborne bacteria known to cause food poisoning in humans. The studies were carried out with two different types of feedstuffs, one containing mostly corn and the other containing mostly grass, to more accurately simulate the diets of grazing cattle or barn fed chickens. We found that both feedstuffs supported volatile fatty acid and methane production but that when any of three different nitrocompounds were added, methane production was significantly reduced. Two of these nitrocompounds caused an increase in the production of beneficial fatty acids whereas the other nitrocompound tested caused a decrease production of a beneficial fatty acid. These results suggest that certain nitrocompounds may be able to be developed into feed additives that can improve the digestive efficiency of sheep, cattle and chickens. Ultimately, this research may help farmers produce healthier more wholesome animal products at less cost for the American consumer.
Technical Abstract: Short-chain volatile fatty acids (VFA) and methane are the products from a wide variety of microorganisms living in animal gastrointestinal systems. The objective of this study was to examine effects of feedstuff and select nitrocompounds on VFA and methane production in in vitro incubations with laying hen cecal contents and rumen fluid from cattle and sheep. In the first experiment, one of the three nitrocompounds was added to incubations containing layer hen cecal contents supplemented with either alfalfa (AF) or layer feed (LF). Both feed material influenced VFA production and acetic acid was the primary component. Incubations with nitroethanol and 2-nitropropanol (NP) had significantly (P<0.05) higher propionate concentration than incubations with added nitroethane (NE). The results further indicated that incubations containing LF produced significantly (P<0.05) more butyrate than AF. Addition of NP and LF to incubations of avian cecal flora may promote gram-positive, saccharolytic, VFA-producing bacteria, especially Clostridium spp. which is the predominant group in ceca. Similar to VFA production, both feed materials fostered methane production in the incubations although methane was lower (P<0.05) in incubations with added nitrocompound, particularly NE. In experiments 3-8, NE was examined in incubations of bovine or ovine rumen fluid or cecal contents containing AF or LF. Unlike cecal contents, LF significantly (P<0.05) supported in vitro methane production of both rumen fluids. The results show that NE impedes methane production, especially in incubations of chicken cecal contents.