Dan Schachner -- the 13-year Puppy Bowl "Ruff-eree" -- joined us Thursday on "TMZ Live" and gave us all the details on the pooches, from big to small, playing in the game. Plus, we had some visitors in our office to highlight the real intent of the event ... getting shelter dogs adopted from Angel City Pit Bull in Los Angeles.

This year, Puppy Bowl is going bigger than ever in several ways -- Dan says there are 131 puppies playing, representing 73 animal shelters across 36 states, the most ever.

Levi the Great Dane is going to check into the game when the bigger dogs get to run in the 4th quarter -- and he's already a whopping 70 pounds at just 3 months old!

On the opposite end of the scale, Dan says the Puppy Bowl's smallest pooch ever will take the field ... Sweatpea is playing the first quarter at a mere 1.7 pounds. Yeah, she can fit in the palm of your hand!

Also new this year is Dan's assistant "Ruff-eree" ... his poodle mix rescue, Whistle.

In addition to Dan getting officiating help, he says you can also expect to see pups in several new off-the-field jobs -- like cheerleading squad and working cameras.

The best part ... Dan says the Puppy Bowl has a 100% adoption rate and helps animal shelters it partners with find new homes for their rescues, thanks to awareness raised on the upcoming TV broadcast.