CORRELATION BETWEEN BREAKDOWN PRODUCTS OF GLUCOSINOLATES AND THE AMOUNT OF RAPESEED MEAL INTRODUCED IN THE DIETS OF 80 LAMBS AND 32 BULLS. EVOLUTIONOF 5-VINYL-1,3-OXAZOLIDINE-2-THIONE (5-VOT) AND THIOCYANATE IONS IN BIOLOGICAL FLUIDS AND ORGANS

A large-scale experimentation has been conducted in Belgium since 4 years in order to study the influence of antinutritional rapeseed factors and their degradation products in ruminants. Animals have been fed with iso-energetic, isolipidic and isoproteic diets containing various proportions of industrial rapeseed meal (lambs: 0% to 40%; bulls: 0% to 34%). The trials and the study of zootechnical, physiological, histological aspects were co-ordinated by the University of Namur. The University of Gembloux was concerned by chemical aspects (analysis of glucosinolates, aromatic choline esters and their respective degradation products such as 5-vinyl-1,3-oxazolidine-2-thione, nitriles, isothiocyanates, thiocyanate ions and trimethylamine). In this presentation we would like to point out the results concerning the evolution of the SCN- ions concentration in plasma, the correlation between the proportions of rapeseed meal in the diets of growing-fattening ruminants and SCN- ions, and 5-VOT content in muscle, some organs (thyroid, kidney, liver and lung), plasma and urine. Correlations (for lambs and for bulls) have been established between thiocyanate ions concentration and the percentage of rapeseed meal in the diets. SCN- ions were specially accumulated in kidney and lung although the 5-VOT is observed in high concentration in thyroid.