As I stated in the other thread you asked, there is no way to know his breed without a pedigree, and no definitive way to tell a bloodline by the looks of a dog. You have a very cute bully breed mutt, as many of us do.
To clarify what BC dogs was saying........... I am going to say this slow so it doesn't get lost in translation. Unless...you...have...a...pedigree...for...your...dog...there...is...NO...WAY...to...tell...what....dog...breed...specifically...your...dog...is!
A pedigree is basically the family tree of the dog. Just like with people I could not say for certain that I was Caucasian from German and Irish decent without my family tree being known. Honestly without knowing that I have also Native American blood from the Cherokee and Blackfoot without my family tree being known. By looking at me other then in the summer you could not tell that I have more then a European decent. So therefore, same goes for dogs you will NEVER know what your dog is without a pedigree.
The APBT does have different bloodlines heck it even has different strains and all those strains have different bloodlines as well. A Strain in this context means "Strain - Biology is several groups of dogs being managed each by a different person." Ex:The Old Family is a strain of a dog breed known as the American Pit Bull Terrier.
Bloodlines however are different they stem from strains most of the time. This however can go either way since a group of individuals not related or a family can pick up and form a strain from a specific bloodline as well."
Bloodline - a group of related dogs being managed by one person." Ex: The Carver bloodline is specific bloodline part of the dog breed known as the American Pit Bull Terrier which was created by Maurice Carver hence the name Carver Bloodline.
As you can see it can be confusing without the proper information.