and

can you say "and" as [ant]?
is it another pronunciation of the word?
i heard a native speaker saying that.

Yes, that can be a native pronunciation of "and". Such a pronunciation is because of final devoicing, which does occur in English dialects, such as those here in parts of the Upper Midwest (even though you would never hear [ant] for "and" here, as the /{/ is raised and often diphthongized when stressed here). However, this is not like final devoicing in, German, Dutch, Polish, or Russian. Unlike their final devoicing, it is generally conditional upon the phonetic environment (following vowels, semivowels, and voiced obstruents tend to suppress it), it leaves behind other phonetic cues such as preceding vowel length which indicate the pre-devoicing phoneme, and it leaves many devoiced obstruents lenis like voiced obstruents (and only in some dialects does it actually make any of them fortis like voiceless obstruent phonemes, and even then it is generally limited to only some phonemes, such as /z Z dZ/ and sometimes /d v/ here).