Yellow-seeded B. napus and B. juncea canola. Part 2. Nutritive value of the meal for turkeys

For the effective utilization of meals derived from the newly developed yellow-seeded canola varieties in turkeys’ diets, it is critical to determine their nutritive value and their impact on growth and digestive physiological responses and the potential benefit of enzyme supplementation. Thus, the standardised ileal amino acid digestibility (SIAAD) and nitrogen-corrected apparent metabolisable energy (AMEn) content of B. napus yellow, B. juncea yellow and B. napus black canola meal (CM) and the effect of feeding 200 g/kg of the meals on growth performance and gut physiological responses with or without a multi-carbohydrase enzyme we determined. For the SIAAD assay, semi-purified diets containing the CM types were fed to turkeys of 21–28 d of age. For the AMEn assay, diets containing 300 g/kg of the CM types without or with a multi-carbohydrase enzyme were fed to turkeys of 35–40 d of age. The growth performance study was a 5 × 2 factorial arrangement to evaluate the effects of feeding 200 g/kg of the CM types (i.e., Control, B. napus black from Canada and Poland, B. napus yellow, and B. juncea yellow) without or with enzyme on growth performance and gut physiological responses of turkeys. There were no differences among CM types in the SIAAD coefficients and AMEn content. Standardised ileal digestible amino acids contents were higher in B. juncea meal (28.3, 15.5 and 14.6 g/kg for arginine, lysine, and threonine, respectively) compared to B. napus yellow (23.7, 18.5, and 14.6 g/kg) and B. napus black (21.5, 17.5, and 13.3 g/kg) meals. The AMEn contents of B. juncea, B. napus yellow, and conventional B. napus black were 9.51, 9.28, and 8.97 MJ/kg, respectively. In the growth performance study, feed intake and body weight gain did not differ among treatments. However, during the starter phase, there was an effect of diet on the feed conversion ratio with B. napus black (Canada and Poland) having the highest. Feed conversion was improved by enzyme supplementation. There was a significant effect of enzyme supplementation on the content of short chain fatty acids in cecal digesta with an increase in acetic and butyric acids, the latter one known to be beneficial in controlling enteric pathogens and in improving gut health. In conclusion, 200 g/kg of all the CM types can be used effectively to replace soybean meal in diets for turkeys when diets are formulated on digestible amino acids and AMEn basis.