If your dog 'song', then let your dog eat his own poop
lah.
If you have issues with that, it's really your own preconceived
ideas of what 'should' or 'should not' be that's the problem, not
your dog's behaviour.
There are healthy bacteria (ie. good bacteria, bad bacteria is
present only in diseased animals) and undigested nutrients in poop,
that the dog intuitive recognizes.
Just because humans find it disgusting and don't do it themselves,
doesn't mean they should impose their preferences and dogma onto
other beings, such as their pets, against their will. Especially by
adding into their food horrible chemicals that taste awful after
undergoing the digestive process. It's kinda cruel.
Please respect the free will of your dog. He never force you to eat
your poop, so please don't force him not to eat his own poop.