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apedcanola seed processing, heat treatment cm effiivef y inactivate the myrosinase enzyme and
lower the glucosinolate content ofthe meai (Fenwick et ai., 1986; Srnithard and Eyre, 1986; Slominski
et al., 1987; Campbell and Slominski, 1990). In aâdition, most of the trypsin inhibitor activity
present in the original product could be destroyed dunng various heat processes. It is generally
agreed that the effectiveness of heat treatment on the nutritive value of feedstuffs depends on a
combination of heating time, temperature, i~tial moisture content and particle size. Tempering the
canola type S. a h seed to 20 % moisture content and micronization at temperatures of up to 1400C
was found to increase protein digestibility in vitro and to lower the activity of myrosinase enzyme
(Kienzle,1998). In addition, micronization and autoclaving of S. a h seed improved tnie
metabohable energy (TMEn) content for cockerels (Kienzle, 1998).
It should be pointed out that the extent of grinding during seed processing would influence the
nutritive value of feedstuffs. In general, " the more finely ground fat-containing raw materials are,
the more highly digestible the fat fraction and the higher the material's ME value " (McNab, 1982).
In studies on the effect of particle size on apparent digestibility of organic matter, crude protein, fat
and apparent metaboliible energy (AMEn) content of rapeseed, it was shown that a reduction in
particle size significantly increased nutrient utilbition by broiler chickens and laying hens (Danicke
et al., 1998). Therefore, it would appear that fine grinding improves the nutritive value of feeds as
a resuh of a more complete destruction of the cell wall structure and release of nutrients otherwise
encapsulated within the cells.
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