This study was conducted to determine if reduced feed intake in broiler chickens fed a diet of high canola meal (CM) is responsible for the reduced growth performance and whether this lower growth rate can be eliminated by increasing dietary amino acid (AA) levels. Five experimental wheat-based diets were formulated as follows: soybean meal (SBM) diet, high CM diet with normal AA concentration, and high CM diets with 3, 6, or 9% additional AA concentration (Lys, Met+Cys, Thr, Ile, Arg, and Val). Another group of birds was pair-fed with SBM diet to the consumption levels observed by the birds fed CM diet with normal AA. There were six replicates of 17 male, 10-day-old Ross 308 chicks per treatment over grower and finisher periods.
Results indicated that the birds fed the CM diets had reduced feed intake and body weighs, but improved feed conversion ratios (P ‹ 0.01) compared to SBM ad libitum fed birds. The SBM pair-fed birds gained the same weight and exhibited similar feed conversions compared to CM fed birds. Birds fed the additional 9% AA treatment had improved feed conversion (P ‹ 0.01) compared to SBM and CM diets with normal AA. No significant differences were observed in ileal digestibility of DM, energy, crude protein, and AA between CM with normal AA and SBM diets. This study showed that reduced growth of birds fed high CM diets is primarily caused by reduced feed intake. This growth depression could partially be overcome by increasing dietary AA levels.