Effect of micronization of full-fat canola seed on performance and carcass characteristics of growing-finishing pigs

Experiments were conducted to determine the effect of micronization (infrared processing) on the nutritive value of full-fat canola seed when fed to growing-finishing pigs (25 to 93 kg). Eighty crossbred pigs (Camborough 15, Pig Improvement Canada) were assigned to one of four dietary treatments in a factorial (sex X treatment) design experiment. The diets consisted of a barley-canola meal based control diet or diets in which canola oil (40 g kg(-1) diet) or canola seed (100 g kg(-1) diet to supply 40 g kg(-1) supplementary oil) were added as a supplementary energy source. Half of the canola seed was fed raw and half was treated by micronization for 35-50 s at 115 degrees C. For the raw full-fat canola seed, the digestibility coefficient for energy was significantly lower (P < 0.05) than that for the control or canola oil supplemented diet while micronization slightly increased energy digestibility. Micronization had no effect on dry matter or protein digestibility. Gilts fed raw canola seed gained weight significantly slower than gilts fed either the control or the canola oil supplemented diet. Micronization was useful in overcoming this growth depression. For castrate males, performance of those fed raw canola seed was equal to castrates fed the diet supplemented with canola oil; therefore, no benefits were seen as a result of micronization. The depression in growth that occurred for gilts fed raw canola seed was associated with a significant (P < 0.05) reduction in feed intake when compared with intakes of either the control or the canola oil supplemented diet. Gilts fed micronized canola seed consumed feed at a similar level to gilts fed the canola oil supplemented diet. There was no difference in feed intake between castrates fed any diet. Feed efficiency for pigs fed any of the lipid supplemented diets was significantly better than that of the control regardless if fed to castrates or gilts. There were no significant differences in carcass traits between castrates fed any of the four diets. In conclusion, the results of this study indicate that micronization of intact canola seed increases growth and feed intake of gilts fed canola seed but not castrates. The mechanism by which micronization improved growth of gilts would appear to be via a reduction in myrosinase activity, thereby reducing the opportunity for hydrolysis of glucosinolates in the gut. (C) 1998 Elsevier Science B.V.