EFFECTS OF AMMONIATION OF CANOLA (LOW GLUCOSINOLATE RAPESEED) MEAL ON ITS NUTRITIONAL VALUE FOR THE RAT

Abstract

Canola (low glucosinolate rapeseed) meal (CM) (Brassica campestris 'Candle') was heated to 105 °C at the desolventizing step (control) or treated with ammonia, steam or both, in addition to heat. These CMs and a commercial CM were incorporated into rat diets at levels providing lysine, the limiting amino acid, at 0.44%. Similar diets contained casein, lactalbumin or soybean meal. All diets were formulated to contain 1.28% nitrogen (air-dry basis). During a 2-wk growth period the feed/gain ratios were higher for rats fed ammoniated CM than for those fed steam-treated meal. Significant differences in gains and feed intakes were not detected. Plasma lysine concentrations were lower (P < 0.05) in rats fed the ammoniated meals indicating decreased absorption of lysine. The performance by rats was generally in agreement with that by growing pigs as reported previously. While ammoniation is effective in reducing the glucosinolate concentrations of CM, this processing step has an adverse effect on the protein quality, particularly lysine availability, of the meal thereby decreasing its nutritional value in swine rations. Key words: Rapeseed meal, canola, ammoniation, protein quality, rats, plasma lysine concentration