The phenolic components of several rapeseed meals were studied in base hydrolyzed extracts as free acids and in 70% aqueous acetone extracts as intact compounds. Thin-layer chromatography, gas chromatography, and mass spectroscopy were used for compound purification and identification. The free acids in the hydrolyzed extracts in order of concentration were: sinapic >> protocatechuic > ferulic > p-hydroxybenzoic > vanillic > syringic. Sinapic acid was the only free phenolic acid detected in the 70% aqueous acetone extracts although there was at least seven other compounds that upon hydrolysis yielded sinapic acid. Neither chlorogenic acid or caffeic acid were detected in any of the meals although they had previously been reported.

Thirty-two samples of rapeseed consisting of eight cultivars (four Brassica napus and four Brassica campestris) grown at four different locations in Western Canada were used to study the effect of cultivar and growing location on the sinapine content of the seed. The results indicated that across location, the B. napus were significantly higher (P < 0.01) in sinapine than the B. campestris cultivars and the R-500 seed was lowest in sinapine content while the Midas seed was highest. While growing location had significant effects on the sinapine content of individual cultivars, no overall significant location effect was observed. The findings suggest that it might be possible, by selection, to develop varieties of rapeseed that are low in sinapine.

White Leghorn male 4-week-old chicks and adult roosters were used to determine the effect of age on the true metabolizable energy (TME) and nitrogen-corrected true metabolizable energy (TME,,) value of ground yellow corn, dehulled soybean meal, wheat shorts, high-glucosinolate rapeseed meal, and dehydrated alfalfa meal. The TME and TME n values of each ingredient were calculated from its gross energy value and the regression of energy voided as excreta on the weight of feed consumed. Variable intakes of corn and soybean meal were obtained with chicks by feeding different amounts of the feedstuffs and with roosters by varying the duration of the feeding period. Variable intakes of the other ingredients were obtained by the force feeding of the birds.The TME values of the feedstuffs in kcal/g of dry matter for chicks and roosters, respectively, were as follows: corn, 3.93 and 3.98; soybean meal, 3.24 and 3.11; wheat shorts, 3.12 and 3.07; rapeseed meal, 2.24 and 2.50; alfalfa meal, 1.22 and 1.38. The TME n values of the feedstuffs for chicks and roosters, respectively, were as follows: corn, 3.76 and 3.88; soybean meal, 2.85 and 2.87; wheat shorts, 2.92 and 2.94; rapeseed meal, 1.99 and 2.24;alfalfa meal, 1.14 and 1.28. The TME values of soybean meal and rapeseed meal for chicks were 104% (P<.05) and 90% (P<.05), respectively, of the values obtained with roosters. The TME n values of corn and rapeseed meal for chicks were 97% (P<.05) and 89% (P<.01), respectively, of the values for roosters. The TME and TME n values of the other feedstuffs were not affected (P>.05) by the age of the bird.It appears that, with the exception of high-glucosinolate rapeseed meal, TME values obtained with adult roosters can be used in the formulation of diets for young growing birds.

No abstract

Two experiments were designed to study the effects of the tannins in rapeseed meal (RSM) on the nutritive value of this feedstuff for chicks.In the first experiment tannins were extracted from RSM and the metabolizable energy (ME) content of the resulting meal was compared against that of the unextracted RSM. The extracted tannins were added to a soybean meal (SBM) containing diet and the ME content of this diet was compared with that of the same diet without added tannins. Results showed that removing the tannins from RSM significantly increased the ME value of the RSM for chicks from 1,171 to 1,844 kcal. per kg. and from 1,253 to 1,766 kcal. per kg. when the determinations were done at 2 weeks and 6 weeks of age respectively. Addition of tannins extracted from RSM to SBM resulted in a reduction in its ME value.In the second experiment, the effect of tannins in RSM on the absorbability of protein by chicks was determined by using regular and tannin-free RSM at the 30% level in rations containing SBM and as the sole source of supplementary protein. Results showed that nitrogen absorption from RSM and tannin-free RSM were 62.6% and 64.2% respectively when fed as part of the nitrogen source and 79.7% and 80.4% respectively when fed as the sole source of nitrogen in the ration. Hence the presence of tannins in RSM apparently had no appreciable effect on nitrogen absorption.