Hydrogen sulfide (H2S) and mercapta

Hydrogen sulfide (H2S) and mercaptan have been
identified as the predominant (80%) volatile S gases
generated under simulated anaerobic fermentation
conditions (Banwart and Brenmer, 1975). Variations in
sulfuric odorous compound concentrations in animal
feces have primarily been attributed to differences in the
sulfur composition of diets fed to the animals, as well
as to the metabolism of sulfur-containing amino acids
(methionine, cystine, and cysteine), which generate
sulfuric odorous compounds such as H2S and mercaptan
(Kiene and Hines, 1995). However, in the present study,
we noted no significant differences in the sulfur composition
and sulfur-containing amino acids of the 4
dietary treatments. Banwart and Brenmer (1975) previously
reported that only 0.03% of the total sulfur
present in swine manure was volatilized to sulfur gases
over a 30-day incubation period, which would provide a
reasonable explanation for the less profound difference
in slurry H2S and mercaptan emissions that was observed
among the treatments in this study.