Interoperable data exchange is crucial for Industry 4.0 (I4.0), allowing value chain partners to share asset information via digital twins. The Asset Administration Shell (AAS) is emerging as the standard, offering a comprehensive object-oriented metamodel and supporting XML, JSON, and RDF serialization for seamless data transmission. In discrete manufacturing, machine-readable and detailed AAS is replacing traditional riveted nameplates for product data exchange. With the growing number of products, organizations must efficiently process these digital nameplates, but XML, JSON, and RDF can be slow and space-intensive, especially since AAS contains a lot of supplementary information to improve semantics. Thus, information exchange would benefit from an efficient serialization format. This work presents a novel approach of serializing AAS content using binary Protocol Buffers (Protobuf) messages, which is faster and more compact. To show the feasibility of our approach, a concrete mapping between Protobuf and AAS is presented, whose practicality is further tested using a series of experiments. The experimental results show that our Protobuf serialization of AAS significantly outperforms standard JSON and XML serialization.