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ARS Home » Plains Area » College Station, Texas » Southern Plains Agricultural Research Center » Food and Feed Safety Research » Research » Publications at this Location » Publication #191996
Title: GASTROINTESTINAL METABOLISM AND PLASMA CONCENTRATIONS OF THE METHANE-INHIBITOR, NITROETHANE, IN FED STEERS

Author
item Anderson, Robin
item Ramlachan, Nicole
item GUTIERREZ, HECTOR
item CARSTENS, GORDON
item MAJAK, WALTER
item Callaway, Todd
item Harvey, Roger
item Horrocks, Shane
item Edrington, Thomas
item Nisbet, David

Submitted to: American Dairy Science Association Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 2/21/2006
Publication Date: 7/9/2006
Citation: Anderson, R.C., Ramlachan, N., Gutierrez, H., Carstens, G.E., Majak, W., McDiarmid, R., Callaway, T.R., Harvey, R.B., Horrocks, S.M., Edrington, T.S., Nisbet, D.J. 2006. Gastrointestinal metabolism and plasma concentrations of the methane-inhibitor, nitroethane, in fed steers [abstract]. Journal of Animal Science. 89(Suppl. 1):128.

Interpretive Summary:

Technical Abstract: To investigate the metabolism and absorption of the methane-inhibitor, nitroethane (NE), we fed 18 steers (403 ± 26 kg BW; mean ± SD) a 50% concentrate diet and administered 0, 80 or 160 mg NE/kg BW per day (6 steers/treatment) for 14 days. Treatments were administered via oral gavage twice daily. Ruminal fluid and feces were collected on days -1, 1, 2, 7 and 14 of treatment; blood samples were collected at 0 and 6 h and at 1, 2 and 7 d of treatment. Rates of NE degradation (dNE/dt) were determined via in vitro incubation. Concentrations of NE in samples collected from the incubations and in plasma were determined colorimetrically. Mean (± SD) NE concentrations in plasma 6 h after initiation of NE treatments were 0.12 ± 0.02 and 0.41 ± 0.05 µmol/ml for steers administered 80 or 160 mg NE/kg BW per day, respectively, thus indicating rapid absorption of NE. Plasma NE concentrations peaked 1 d after initiation of the 80 or 160 mg NE/kg BW per day treatments (0.38 ± 0.10 and 1.14 ± 0.06 µmol/ml, respectively). Plasma NE concentrations declined thereafter to 0.25 ± 0.14 and 0.78 ± 0.28 and to 0.18 ± 0.06 and 0.44 ± 0.34 µmol/ml on days 2 and 7 for the 80 or 160 mg NE/kg BW per day treatment groups, respectively, thus indicating decreased absorption or more rapid excretion or metabolism of the compound. An analysis of variance revealed that ruminal dNE/dt from steers administered NE were more than 2.5-fold higher (P < 0.05) than the mean (± SD) rate observed in steers administered no NE (0.051 ± 0.02 µmol NE/ml ruminal fluid per h). This observation suggests an enrichment of NE-degrading bacteria in the rumen of both groups of NE-treated steers. Fecal dNE/dt (0.067 ± 0.04 µmol NE/g feces per h) were unaffected by treatment thus indicating that NE was not present at high enough concentrations in the lower gut to affect a similar enrichment of NE-degrading bacteria in these steers.