OMAHA, Neb. (AP) — Nebraskans know where their meat comes from: the farms, ranches, feedlots and packing plants that make the state the nation's top beef producer and a growing supplier of pork and poultry.

But what happens to the Beef State's massive livestock industry if Americans switch to "meat" made from plant protein — or from muscle tissue grown not on farms but in big industrial tanks?

It might sound far-fetched, but the plant products have launched and the factory-grown meat may be about to, with claims they are better for the environment than meat from livestock, and taste just as go...