You can read alot of technical books online for free at this site.

Here is one on Amino Acids:

https://darwin.nap.edu/books/0309063469/html

You can start from this page, and just type in a subject in the Discovery Engine at the top of the page, and it will bring up a list of books on that subject. Try typing in "iodine" and see the list on that subject. Looks interesting.

Here is one on the Nutrient requirements of Dogs and Cats:

https://newton.nap.edu/catalog/10668.html

Here's one on Trans Fats:

https://newton.nap.edu/catalog/1222.html#toc

Note: You can copy and paste from these online texts.