Effects of canola meal source on the standardized ileal digestible amino acids and apparent metabolizable energy contents for broiler chickens*
Two studies were conducted to determine the effect of canola meal source on the standardized ileal digestible amino acids (AA) and nitrogen-corrected apparent metabolizable energy (AMEn) contents of canola meal (CM) from 6 processing plants in Canada. Two plants provided CM in both mash and pellet forms, while the other 4 provided CM in mash form only, giving a total of 8 samples. In the standardized ileal digestibility (SID) assay, 280 birds were housed 7 per cage and fed a commercial starter diet from 1 to 14 d of age followed by the test diets from 15 to 21 d. Diets were formulated to contain CM as the only source of protein. Chromic oxide was included in all diets as an indigestible marker. Diets were randomly assigned to 5 cages of 7 birds. On d 21, birds were euthanized by CO2 asphyxiation and digesta samples were collected from the terminal ileum for SID of AA. The SID values were calculated using ileal endogenous AA losses determination. In the AMEn assay, 330 birds were housed 6 per cage and fed a commercial starter diet from 1 to 14 d of age followed by the experimental diets from 15 to 19 d. The 8 experimental diets contained 30% of CM and 70% of a corn-soybean meal-based diet. There were differences (P < 0.05) among CM samples in the standardized ileal digestible content of all AA. Standardized ileal digestible contents of Arg, Lys, Met, and Thr averaged 2.17, 1.74, 0.53, and 1.03%, respectively. Pelleting reduced (P < 0.05) the standardized ileal digestible content of all AA in CM from one of the plants. There were differences (P<0.05) among CM samples in the AMEn contents with values ranging from 1,590 to 2,041 kcal/kg DM. In conclusion, there was effect of CM source on the standardized ileal digestible AA and AMEn contents. Regression equations for predicting standardized ileal digestible contents of selected AA from a simple measure of acid detergent fiber (ADF) were developed.