Valorisation du tourteau de colza. 1. — Influence de l'élimination des glucosinolates, du dépelliculage et de l'extraction des alpha galactosides sur sa valeur nutritive. Étude sur le rat en croissance

Valorization of rapeseed meal. 2. Nutritive value of high or low-glucosinolate varieties and effect of dehulling

“…Dehulling the Tandem rapeseed did not markedly increase its total glucosinolate, ITC and VTO contents, although the glucosinolate content is lower in hulls than in kernels (Bayley and Hill, 1975 ;Bell and Shires, 1982 (Vermorel, Davicco and Evrard, 1987). Similarly, the 50 % reduction in the weight of the gut contents of rats fed dehulled rapeseed meal agrees with earlier results (Vermorel, Fayet and Baudet, 1978), and may be explained by reduced fermentation in the caecum and large intestine.…”

“…In contrast, oil extraction appears to have been complete since the gross energy contents of the meals were very similar. The 17-point improvement (30 %) in energy digestibility and 6 to 10-point (9 to 15 %) improvement in protein digestibility agree with results obtained on rats (Vermorel, Fayet and Baudet, 1978) and on pigs (Bourdon, 1986 (Sauer et al, 1982). In contrast, the performances of rats fed dehulled Tandem meal were not reduced in spite of the theoretical lysine deficit of the diet (7.2 vs 8.5 g/kg), taking into account the ileal digestibility of rapeseed lysine reported in pigs by Sauer et al (1982).…”

“…(Vermorel, Fayet and Baudet, 1978). The Tandem rapeseed meal was the sole protein source of the T and TD diets.…”

Valorization of rapeseed meal. 3. Effects of glucosinolate content on food intake, weight gain, liver weight and plasma thyroid hormone levels in growing rats

“…The effect probably increases with increasing dietary glucosinolate concentrations (Vermorel, Fayet and Baudet, 1978), at very low levels, plasma T 4 content is not reduced in rats ; similarly, in pigs the size and structure of the thyroid gland are not altered (Thomke, 1984). In contrast, at relatively low glucosinolate concentrations (4.4 mM/kg), plasma T 4 and T 3 contents are reduced by 65 and 50 %, respectively, showing that in rats, as in pigs, the functioning of the thyroid is very sensitive to the presence of glucosinolates.…”

“…The meals obtained from the first new rapeseed cultivars bred in France (Morice, 1974) or in other countries (Tower, Line and Erglu) had very low glucosinolate contents (8 to 15 mM/kg of dry matter, DM) which permitted their use at high concentrations in animal feeds (McKinnon and Bowland, 1977 ;Vermorel, Fayet and Baudet, 1978 ;review by Rundgren, 1983 ;Thomke et al, 1983 ;Bell, 1984). However, their agronomic yield was low.…”