تعيين قابليت دسترسي اسيدهاي آمينه دانه ذرت با استفاده از خروس بالغ

Determination of Availability of Amino Acid in Maize Using Cockerels

The experiment was carried out to determined the apparent digestibility and true amino acid availability of maize. Rhode Island Red (RIR) adult cockerels (44 birds) were used in bioassay, under standard conditions. Before beginning of experiment, 44 birds were withheld from feed for 24 hours to ensure that no feed residues remained in their alimentary tracts. The experimental period was 6 days: a 3-day pre collection period and 3-day collection period. The experiment was designed so that 10 grams of maize were fed to 6 groups of adult cockerels. Additional 6 birds were given no feed and served as negative controls to provide a measure of the endogenous amino acid losses (EAAL). The samples of dropping voided during the 48-hours period were collected, weighted and frozen. Samples dried at 90o C over night then ground and assayed for amino acid concentrations by high performance liquid chromatography (HPLC). The result of experiment demonstrated the regression equation (Y = l/37+0.07x), with intercept (1/37 g/kg) and regression coefficient (0/073). The correlation coefficient and standard error means (SEM) were 0/65 and 2/24 respectively. The mean apparent and true available amino acid values obtained by CAM for maize were 5/03 ± 0.25 and 7/09 ± 0/17 grams respectively. It can be seen that at zero amino acid intakes, the amino acid voided (i.e. the EAAL) were 58/85 gram. The apparent amino acid availability of maize increased in a curvilinear manner with maize input. The reason may be that the metabolic plus endogenous amino acid losses (EAAL) are changed against the maize input. Support for this is the uniformity of the true available amino acid values. Finally the use of available amino acids in practical feed formulation is considered. Because differences were observed for individual amino acids of maize for birds.