I would like to prevent iNOS activity in mice. Based on literature, I chose aminoguanidine as the inhibitor to be administered p.o. in drinking water. Which of these two compounds (http://www.sigmaaldrich.com/catalog/product/sigma/a7009 and http://www.sigmaaldrich.com/catalog/product/aldrich/396494) would you recommend to use, have you tried any of them? They both seem to be very similar...
Furthermore, have you ever tried to apply any iNOS inhibitor to birds, especially ducks?
Just check solubility and solution stability since you mentioned p.o. it will contact to HCl in stomach and form of this inhibitor makes no difference.
You can try 1400W, a relatively specific inhibitor for iNOS, which works in mouse and other mammalian cells pretty well.
Sequence homology of iNOS in chicken and mouse, is as such:
http://www.jbc.org/content/271/20/11911.full.pdf
But if the binding site is conserved, then homology differences across species won't matter much.
Aminoguanidine is not very specific and requires high doses. It blocks also eNOS, and nNOS. If the treatment is long, then the drug will negatively affect normal physiology, irrelevant to your question.
1400W blocks NO and peroxynitrite production in inflammed cells (overnight treatment). See:
http://www.ncbi.nlm.nih.gov/pubmed/25058034