Abstract:
Three experiments were conducted to determine the AID and SID of protein and AA in pea protein isolate(PPI), distiller's dried grains with solubles derived from a blend of wheat and corn (wcDDGS) and corn. In addition, 2 experiments were conducted to estimate the requirements of digestible SAA (dSAA) and digestible lysine (dLYS)for 3-week old broilers to obtain optimum growth performance(BWG,FCR),and optimum yield performance(CY, BMY and TDY). For digestibility studies, day-old male Ross 308 broiler chicks were fed test diets from day 1-14. The test-diets were balanced for vitamins and minerals and contained chromic oxide (0.3%) as an indigestible marker. The protein and AA digestibilities were determined either by direct or indirect method. For requirement studies, day-old male Ross 308 broiler chicks were fed lysine- or SAA deficient basal diets balanced for all other AA, except for the AA under test, according to the ideal protein concept. All test diets were also balanced for vitamins and minerals and were kept isonoitrogenous and isocaloric within each assay. The average SID estimates (%)of AA were 92.4, 71.5 and 93.3 in PPI, wcDDGS and corn, respectively. Using regression analysis, the dietary dLYS requirement estimates(%) were 1.12 and 1.13 for BWG and FCR, respectively. The dietary dSAA requirement estimate was 0.81% for BWG while no significant response was observed for FCR. Both CY and BMY increased cubically with increasing levels of dLYS, whereas, CY didnot respond significantly and BMY increased linerally with the increasing levels of dSAA.
