Chemical composition and nutritive value of canola-quality Brassica juncea meal for poultry and the effect of enzyme supplementation

Canola breeding program undertaken to improve meal quality has led to the development of canola quality (i.e., low-glucosinolate, low-erucic acid) form of B. juncea, a mustard species known for its pure yellow seed coat. Under Western Canadian conditions, B. juncea suffers less from heat and drought stress and matures earlier than B. napus. Such characteristics are the basis for high yields of oil and low chlorophyll content in the seed. The objective of the current study was to evaluate the chemical and nutritive composition of meals derived from pre-press solvent extracted seeds of the conventional black-seeded B. napus canola and the canola-quality yellow-seeded B. juncea. In comparison with B. napus canola, meal derived from yellow-seeded B. juncea contained, on dry matter (DM) basis, similar amount of protein (417 vs. 415 g/kg) and fat (28 vs. 29 g/kg), more sucrose (69 vs. 56 g/kg), more starch (34 vs. 10 g/kg) and less dietary fibre (277 vs. 338 g/kg). Lower fibre content of B. juncea canola was reflected in lower content of lignin with associated polyphenols (40 vs. 104 g/kg). The nutritive value of canola meals was investigated with broiler chickens fed maize/soybean meal-based diets containing 300 g/kg of meals from 4 to 18 d of age. A lower (P < 0.05) body weight gain (BWG) was observed in birds fed the B. juncea diet when compared with those fed the conventional black-seeded B. napus canola (479 vs. 515 g/bird). No difference in feed conversion ratio (FCR) was observed (1.44 vs. 1.42). Meal apparent metabolisable energy (AMEn) values for B. juncea and B. napus were determined with broiler chickens (from 14 to 19 d of age) and were 7.9 and 7.8 Mj/kg DM, respectively. Enzyme (multi-carbohydrase) addition resulted in the AMEn value of 8.3 Mj/kg DM for B. napus meal, with a more pronounced effect (P < 0.05) observed for B. juncea canola (from 7.9 to 9.3 Mj/kg DM). In the third study, growth performance of broiler chickens fed 15% of canola meals without and with enzyme supplementation was determined in the starter (1-21 d of age) and grower (22-35 d of age) phases of the experiment. Compared to the soybean meal (SBM) Control, canola meals decreased BWG of broiler chickens in the starter phase and the entire trial. Enzyme supplementation improved FCR in the chicks fed B. juncea meal (P < 0.05). The enzyme effect was more pronounced in the young birds.