Artigo definido "Os" in this sentence will emphasize the "Meus gatos" and not any (quaisquer) "gatos" but "Meus gatos". And pay attention to the plural: O meu gato; Os meus gatos

Hi there, I believe both are correct. But thinking about it, I frequently say "os meus gatos ... " instead of just "meus gatos" ...

I have answered this question a couple of times before here on italki. You can check it out here, for instance: https://www.italki.com/question/410041 Long story short, the definite articles are optional before possessive pronouns in Brazilian Portuguese, but mandatory in European Portuguese. Therefore, 'meus gatos' for BP and 'os meus gatos' (not 'o meus gatos') for both.

There's no difference. We usually don't say the article OS, it's implicit. But if you're in a formal conversation you should say it. It looks more polite.

Olá Josh, as duas formas são usuais, no entanto é legal voce se acostumar a usar os artigos definidos "o, a, os, as" e indefinidos "um, uma". Isso vai ajudar você a entender melhor nosso idioma.