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ABS TRACTThe non-starch polysaccharide (NSP) content as determined by gas chromatography (component neutral sugars) and colorimetry (uronic acids) was shown to be 16-22% in ten different samples of defatted canola (lowglucosinolate rapeseed) seed. The non-cellulosic components of NSP accounted for 13-16% of the meal and on average consisted of arabinose (33 %), xylose (13 %), galactose (13 %), glucose (5 %), mannose (3 %), rhamnose (2%), fucose (2 %) and uronic acids (30 %). Yellow-seeded and brown-seeded samples of canola contained similar contents of total dietary fibre although the composition of the fibre components tended to differ with the former showing a low content of lignin and associated polyphenols and a high content of NSP as compared with the latter type. NDF values tended to be lower for yellow-seeded than for brown-seeded canola due to the relatively high content of NSP in neutral detergent solubles of yellow-seeded canola.An initial balance study with laying hens showed low ( c 3 %) digestibility of the polysaccharide components, and juther studies were conducted with a commercial enzyme preparation (SP249, Novo Laboratories Ltd, Lachine, Quebec) to enhance the in-vivo hydrolysis of the NSP @action of the meal.Laying hens were fed a semipurified diet containing 40 % commercial canola meal with and without enzyme (1 %). NSP digestibility was increased to 37% by the enzyme supplementation.

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The effects of feeding rapeseed meals (RSM) containing low (Tower) or high (Target/Turret) levels of glucosinolates on thyroid status, iodine and glucosinolate content of milk and other parameters were studied in dairy cows and young calves. RSM (Tower and Turret) fed to dairy cows at 25% of the grain mixture reduced iodine content of milk. Diets containing Tower and Turret RSM tended to reduce plasma thyroxine (T4) in cows and increase the size of thyroids in rats. Calf diets containing Target and Tower RSM resulted in increased liver and thyroid weights, but only those containing Target tended to reduce plasma T4 levels. Feed intake, weight gain, hemoglobin, blood cell volume and erythrocyte count in calves were not affected by diets containing Tower RSM, but Target RSM reduced all these parameters. In addition, diets containing Target caused more pronounced histological changes of the calves' thyroid than those containing Tower RSM. No measurable amounts of intact glucosinolates were detected in milk of cows fed RSM. Similarly the glucosinolate aglucones, isothiocyanates or vinyl oxazolidinethione, were not transferred to milk although small amounts of unsaturated nitrile (1-cyano-2-hydroxy-3-butene) and inorganic thiocyanate were detected in milk. Rats receiving milk from cows fed Turret RSM developed larger thyroid than those receiving milk from control-fed cows. Supplemental iodine (61.0 microgram/d) in the rat prevented the thyroid enlargement.