effects of bioassay and age on amino acid digestibility and metabolizable energy of soybean, sunflower and canola meals

these experiments were conducted to determine metabolizable energy and amino acid digestibilities of soybean meal, sunflower meal and canola meal in broiler chickens by using titanium oxide as indigestible marker in intact or caecectomized cockerels. ileal and total tract digestibility of amino acids were measured using broiler chickens, moreover, digestibility were also determined in the intact and caecectomized cockerels. the mean excreta apparent and true digestibility of amino acid in broiler and intact cockerel were 76.99, 78.07 and 84.18, 88.35 for soybean meal 92.16, 92.84 and 78.09, 85.94 for sunflower meal and 69.82, 70.22 and 86.47, 88.50% for canola meal respectively. the mean values of ileal apparent and true digestibilities (standardized ileal digestibility) of amino acid in broiler were 72.18, 73.12 for soybean meal; 47.48, 48.47 for sunflower meal and 62.05, 62.45% for canola meal respectively. the mean values of apparent and true digestibilities of amino acid obtained from caecectomized cockerel and broiler were 80.34, 84.45 for soybean meal, 74.48, 82.47 for sunflower meal and 84.74, 87.12% for canola meal respectively. the experiments shown that apparent amino acid digestibility of soybean (9 to 11%), sunflower (34 to 50%) and canola meals (19 to 27%) from broiler (excreta and ileum), were lower than those intact and caecectomized cockerel. the result of experiments indicated that apparent metabilizable energy (ame), true metabolizable energy corrected for nitrogen (amen), true metabolizable energy (tme) and nitrogen correction of true metabolizable energy (tmen) values for canola and sunflower meals at 21 and 42 d broiler were significantly higher than cockerels. however, data shown that amount of metabolizable energy obtained from canola and sunflower meals were higher than those of broiler excreta or ileal and caecectomized cockerels.