N-Nitroso Compound Precursors in some Nigerian Forage Crops

Primary and secondary amine contents of some dried Nigerian forages were analyzed as their sulphonamides by gas chromatography interfaced with a chemiluminescence detector-Thermal Energy Analyzer modified for use in nitrogen mode. Both nitrate and nitrite were analyzed spectrophotometrically using an automated dual channel continuous flow nitrate-nitrate analyzer as nitrite following cadmium reduction of nitrate to nitrite and diazotization of nitrite with sulphanilamide, and coupling with N-(1-naphythyl) ethylenediamine. Secondary amines detected in the forage were diethylamine, dimethylamine, methylbenzylamine, piperidine, methylamine, while primary amines found include n-butylamine, ethylamine, methylamine, isopentylamine and propylamine. Total secondary amines were highest in Urena lobeta (92.7 ppm), but lowest in Dichrostachys cinera (5.6 ppm), while total primary amines were also highest in Urena lobeta (94.7ppm) but lowest in Rottboellia exaltata (8.4 ppm). Only trace amounts of nitrite were detectable in some samples. The toxicological relevance of these findings are discussed with respect to potential endogenous formation of hepatotoxic, mutagenic and carcinogenic n-nitroso compounds in animals, and the consequences of this phenomenon on animal health and production. Keywords: N-nitroso precursors, forages, Nigeria Trop. Vet. Vol. 21 (2) 1-8 (2003)