EFFECTS OF AMMONIATION ON THE COMPOSITION AND NUTRITIONAL QUALITY OF LOW GLUCOSINOLATE RAPESEED (CANOLA) MEAL

Abstract

Commercial No. 1 Candle rapeseed (canola) (Brassica campestris) was prepress solvent extracted and heated to 105 °C at the desolventizing step (control meal). Samples of the canola (low glucosinolate) meal were also treated with ammonia or steam or both at the desolventizing step. The meals were analyzed chemically and subsequently fed to 70 growing pigs in a factorial experiment. Digestibility of the meals was determined separately. Ammoniation increased the crude protein (% N × 6.25) concentration from 39 to 42%, decreased the proportion of alkaline soluble nitrogen and increased the available lysine level. Both ammonia and steam reduced glucosinolate concentrations but usually at least half the glucosinolates remained after any treatment. Compared with a soybean meal control diet, diets containing 10% treated canola meals did not affect daily gains, feed intakes or feed:gain ratios when fed to pigs. Ammoniation had little effect on crude protein digestibility of canola meal but, in combination with steam, reduced the energy digestibility. Based on these results, there appeared to be no advantage in ammoniating canola meal as a means of improving its nutritional quality in swine diets. Key words: Rapeseed meal, low glucosinolate, ammoniation, nutritional quality, composition, pigs