Free amino acids in milks of human subjects, other primates and non-primates.

The research article studies the levels and types of free amino acids in the milk of various species, including humans, non-human primates, and non-primates. The researchers used specific scientific methods to analyze the free amino acids and observed that the milks of each species had unique amino acid patterns.

Methodology

• The researchers gathered samples of preterm and term transitional milks from humans, along with mature milks from non-human primates and non-primate species.
• They then used a method called precolumn phenylisothiocyanate derivatization and liquid chromatography to analyse the free amino acids in these samples.

Results and Observations

• The study found that the differences in free amino acids between the three types of human milk were minor.
• The milks from pinnipeds (seals and sea lions) contained the highest levels of total free amino acids, with concentrates ranging from 8634 to 20,862 micro-mol/liter.
• The milks of cows and sheep had the lowest levels of total free amino acids, measured at 1061-1357 micro-mol/liter.
• Intermediate levels of total free amino acids (3069-7381 micro-mol/liter) were found in the milk from human subjects, chimpanzees, gorillas, elephants, horses, and pigs.
• Glutamic acid was the most abundant free amino acid in milks of humans, non-human primates, elephants, horses, and cows.
• Taurine was the most abundant free amino acid in milks of pinnipeds, pigs, goats, and sheep. It was also the second most abundant in human and non-human primate milks.
• For pinniped milk, histidine was the second most abundant free amino acid.

Conclusions

• The study concludes that the milks of each species had distinct free amino acid patterns. This pattern could potentially reflect the relative importance of the free amino acids during the early stage of postnatal development for each species.
• Understanding the specific amino acid content in different types of milk can be crucial because amino acids play fundamental roles in growth, immunity, and overall health across species.