FREE AMINO-ACIDS IN MILKS OF HUMAN-SUBJECTS, OTHER PRIMATES AND NONPRIMATES

Preterm and term transitional milks of human subjects and mature milks of human subjects, nonhuman primates and non-primates were analysed f or free amino acids (AA) using precolumn phenylisothiocyanate derivati zation and Liquid chromatography. Differences in free AA between three types of human milk were small. Milks of pinnipeds (seals and sea lio ns) contained the highest levels of total free AA (8634-20862 mu mol/l ), while the milks of cows and sheep had the lowest levels of total fr ee AA (1061-1357 mu mol/l). The milks of human subjects, chimpanzees ( Pan troglodytes), gorillas (Gorilla gorilla), elephants (Elephas maxim us), horses and pigs had intermediate levels of total free AA (3069-73 81 mu mol/l). Glutamic acid was the most abundant free AA in milks of human subjects (1339-2157 mu mol/l), non-human primates (423-2528 mu m ol/l), elephants (1332 mu mol/l), horses (1119 mu mol/l), and cows (34 9 mu mol/l). Taurine was the most abundant free AA in milks of pinnipe ds (5776-13643 mu mol/l), pigs (1238 mu mol/l), goats (1150 mu mol/l) and sheep (341 mu mol/l). Taurine was the second most abundant free AA in milks of human subjects and non-human primates, while histidine wa s the second most abundant free AA in milks of pinnipeds. Milks of eac h species had a distinctive free AA pattern which may reflect the rela tive importance of the free AA during early postnatal development.