Effects of select nitrocompounds on in vitro ruminal fermentation during conditions of limiting or excess added reductant.
Ruminal methane (CH(4)) production results in the loss of up to 12% of gross energy intake and contributes nearly 20% of the United States' annual emission of this greenhouse gas. We report the effects of select nitrocompounds on ruminal fermentation after 22 h in vitro incubation (39 degrees C) with or without additions of hydrogen (H(2)), formate or both. In incubations containing no added reductant, CH(4) production was inhibited 41% by 2-nitro-1-propanol (2NPOH) and >97% by 3-nitro-1-propionic acid (3NPA), nitroethane (NE) and 2-nitroethanol (2NEOH) compared to non-treated controls and H(2) did not accumulate. With formate as the sole added reductant, nitro-treatment reduced CH(4) production by >99% and caused 42% to complete inhibition of formate catabolism compared to controls, and the accumulation of H(2) increased slightly. Nitro-treatment decreased CH(4) production 57-98% from that of controls when supplied H(2) or formate plus H(2). Formate catabolism was decreased 42-84% from that in controls by all nitro-treatments except 3NPA with both formate and H(2). Greater than 97% of the added H(2) was catabolized within controls; >84% was catabolized in nitro-treated incubations. Acetate, propionate and butyrate accumulations were unaffected by nitro-treatment irregardless of reductant; however, effects on ammonia and branched chain fatty acid accumulations varied. These results suggest that nitro-treatment inhibited formate dehydrogenase/formate hydrogen lyase and hydrogenase activity.
United States Department of Agriculture, Agricultural Research Service, College Station, TX 77845, USA. anderson@ffrsu.tamu.edu
Robin C
RC
Anderson
Nathan A
NA
Krueger
Thaddeus B
TB
Stanton
Todd R
TR
Callaway
Thomas S
TS
Edrington
Roger B
RB
Harvey
Yong Soo
YS
Jung
David J
DJ
Nisbet
D000085:Acetates / Q000032:analysis; D000641:Ammonia / Q000032:analysis; D000818:Animals; D002417:Cattle; D005232:Fatty Acids, Volatile / Q000032:analysis; D005285:Fermentation / Q000187:drug effects*; D008697:Methane / Q000378:metabolism; D009574:Nitro Compounds / Q000378:metabolism / Q000494:pharmacology*; D010084:Oxidation-Reduction / Q000187:drug effects; D011422:Propionates / Q000032:analysis; D019163:Reducing Agents / Q000494:pharmacology*; D012417:Rumen / Q000187:drug effects* / Q000382:microbiology
D000085:Acetates; D005232:Fatty Acids, Volatile; D009574:Nitro Compounds; D011422:Propionates; D019163:Reducing Agents; D000641:Ammonia; D008697:Methane