Is it better to load data from a .txt file or from a preloaded SQLite database into a private database?

I'm working on an Android app and I wonder if it is better to load data from a .txt file or from a preloaded SQLite db.

When I take data from a .txt file, I do the following: ("insertar" is a function that inserts key and value into db)

while ((line = buffreader.readLine()) != null) {
    keyValue = new String[2];
    keyValue = line.split("_");
    insertar(keyValue[0], keyValue[1]);
}

I haven't coded a function to copy data from a preloaded database yet.

Do I have any other option in order to be as fast as possible on the first app launch? Which is the most performant method to load data?