Glucosinolates metabolites in plasma, milk and thyroid of gestating and lactating ewes

Poster (2003)

The effects of high level of rapeseed meal in the diet on the concentration of antinutritional factors (glucosinolates metabolites) in blood plasma, milk and thyroid were studied in 90 ewes. From the ... [more ▼]

The effects of high level of rapeseed meal in the diet on the concentration of antinutritional factors (glucosinolates metabolites) in blood plasma, milk and thyroid were studied in 90 ewes. From the 100th day of gestation, ewes bearing two foetuses were divided into three groups and were fed with pasture hay ad libitum and 500 g/d of diet containing 0 or 40% rapeseed meal obtained from either Apex or Synergy variety. During the 47 first days of lactation, 1200 g/d of the same meal were given. Thereafter, during 3 weeks, the ewes were only fed with hay. Blood and milk samples were taken fortnightly for the determination of SCN- and 5-vinyl-1,3- oxazolidine-2-thione (5-VOT) concentrations. One ewe from each group was slaughtered at the end of rapeseed meal distribution and another one three weeks later for thyroid analyses. SCN- and 5-VOT concentrations in blood plasma increased significantly (P<0.05) and regularly until one month of rapeseed supplementation to the withdrawal of rapeseed in the diet. One to three weeks after the end of rapeseed meal distribution, the SCN- and 5-VOT plasma concentrations came back at the basal level. Some changes were also observed for SCN- and 5-VOT contents in milk. The results indicated a great capacity of the ewes to excrete SCN- and 5-VOT by the milk. A 5-VOT accumulation was observed in the thyroid according to the level of progoitrin in the diet, but no SCN- accumulation. The 5-VOT concentration in thyroid of the ewes fed during three weeks with hay came back to zero. The thyroid analysis showed the reversible aspect of the thyroid hypertrophy due to 5-VOT accumulation. [less ▲]

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

Conference (1999)

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 ... [more ▼]

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. [less ▲]

OPTIMAL LEVEL OF RAPESEED MEAL IN DIETS OF LAMBS.

Poster (1999)

Two experiments were carried out in order to improve the strategy of rapeseed meal (RPM) incorporation in the diets of lambs. In a first experiment, the effects of RPM obtained from either a high ... [more ▼]

Two experiments were carried out in order to improve the strategy of rapeseed meal (RPM) incorporation in the diets of lambs. In a first experiment, the effects of RPM obtained from either a high-glucosinolate (HG) cultivar (Honk RPM) or a double-low strain (Samourai RPM) were studied. Two types of concentrates containing 25% of RPM were compared to a Control concentrate. In a second experiment, the effects of various proportions (0 – 40%) of an industrial low glucosinolate (LG)-RPM were studied in order to determine the disorder-threshold in diets for young ruminants. One hundred forty six Texel, Suffolk or crossbred lambs ranged in age from 1 to 2 months were used. Neither the Samourai nor the Honk RPM did affect negatively animal performance whatever the parameter considered (growth, food intake and conversion, slaughter performances). Low (P < 0.05) proportions of C10:0, C12:0 and C14:0 and high contents of C18:1trans, C22:2 were determined in the perirenal fat of lambs receiving the Honk RPM. The industrial LG-RPM had no negative effects on animalperformance, best results were obtained with 25 and 30% of RPM. The Samourai RPM had no effect on the thyroid weight, whereas, the Honk RPM modified (P < 0.05) the histology of this organ; the percentages of large thyroid follicles being higher (P < 0.05) in the Honk group than in the Control and Samourai groups. High levels of Canola industrial LG-RPM(from 20%) induced also an hyperthyroidism. The Samourai and Honk RPM decreased (P < 0.05) the secretions of thyroid hormones while the industrial LG-RPM did not affect these hormones in any way. RPM had no significative effects on other hormones. It was concluded that disturbance in thyroid histology and activity induced by the ingestion of RPM did not affect the physiology and performance of lambs and that the levels between 25 to 30% of a LG-RPM were optimal for growing and fattening lambs. [less ▲]