The objective of the study was to determine whether bioavailability of methionine hydroxy analogue free acid (MHA-FA) is higher than 65%, in product basis, for 24 to 40 week-old laying hens. Six hundred and forty 24-week commercial laying hens were used in four 28-day experimental periods in a randomized complete design with ten treatments, eight replications and eight birds per experimental unit. The treatments were based on a basal feed deficient in methionine, containing 2,830 kcal metabolizable energy (EM)/kg and 14.5% crude protein (CP), with 0.23% and 0.21% total and digestible methionine, respectively, supplemented with DL-methionine 99% - DLM (0.0325; 0.05; 0.065; 0.0975; 0.10 and 0.15%) and MHA-FA (0.05; 0.10 and 0.15%). The following variables were assessed: body weight (kg), egg production (%), egg mass (g), egg weight (g), feed intake (g), feed conversion (g/feed/egg). Based on the egg production evaluation, egg mass and feed conversion, the bioavailability of MHA-FA was estimated at 74.66, 73.97 and 71.17%, respectively, giving MHA-FA an average bioavailability of 73.22% compared to DLM on product basis. The MHF-FA bioavailability was higher than 65% on product basis.
base product; DLM; heat stress; laying hens; MHA-FA
