Biotin bioavailability of protein supplements and cereal grains for starting turkey poults

Biotin bioavailability was estimated in canola meal (CM), various cereal grains, and protein supplements using turkey poults in a growth bioassay study. Following a 10-day pretest period to deplete the biotin reserves of newly hatched poults, triplicate groups (seven poults each) were fed a basal diet without added biotin, or supplemented with graded levels of d-biotin (100, 200, and 400 micrograms/kg) for 21 days. Poult growth (y, g/day) was positively related to biotin intake (x, micrograms/day), as follows: y = 3.05x + 4.32, r = .997 (P less than .01). Similar groups of poults were fed test ingredients: CM, soybean meal (SBM), or soyprotein isolate (SPI) incorporated at levels of 25% into the diet by partial replacement of casein and carbohydrates; other poult groups were given cereal grain (25%) or cereal grain (25%) + CM (25%) included in the SPI-based diet. Use of the regression equation to compute bioavailable biotin gave bioavailability values (in percentages) that were low for triticale (15.9), wheat (17.0), barley (19.2), and sorghum (29.5), moderate for CM (65.4) and SBM (76.8), and high for corn (95.2). The combination of CM and cereal substantially increased the total biotin available for poult growth, with individual biotin contribution being strongly additive for CM plus barley, sorghum, or wheat, but less so in case of CM plus corn or triticale diets. Therefore, CM seems to be a good source of bioavailable biotin for starting poults. Increased levels of bioavailable biotin reduced the incidence of pathological signs (dermatitis, hock disorders, and broken feathers) and also poult mortality.(ABSTRACT TRUNCATED AT 250 WORDS)