BIOLOGICAL EFFICACY FOR GROWING CHICKS OF THREONINE IN A NEW-TYPE OF SUPPLEMENT OBTAINED FROM THE FERMENTATION BROTH OF L-THREONINE PRODUCTION

In 2 experiments with growing broilers 10 or 8 to 29 days of age, the biological efficacy of threonine in form of a new type of preparation containing approximately 23% L-threonine together with part of the thr eonine fermentation broth was estimated in comparison to crystalline L -threonine feed grade. Threonine was added at 2 levels to a basal diet deficient in threonine, but adequate in all other nutrients, either a s crystalline L-threonine or in 2 test preparations. From multi-expone ntial or Slope Ratio regression analysis, the relative biological effi cacy of threonine in the 2 preparations was estimated to be 110% and 1 11% for weight gain and 145% and 114% for feed/gain, respectively. Non e of these estimates was significantly different from 100%. It is conc luded that the biological efficacy of threonine in the tested preparat ions is equivalent to crystalline L-threonine 98%.