The explicit message of ''Animal Liberation,'' a collection of songs by British and European performers, is that ''Animals are not ours to eat, wear or experiment on.'' Unlike the majority of recent benefit albums, it pounds home its message with grim lyrics, collaged news reports and ominous-to-danceable electronic dance rhythms. It's not for the squeamish. Performers who wrote or contributed songs - presumably all vegetarians - include Lene Lovich (solo and in a duet with Nina Hagen, ''Don't Kill the Animals''), Shriekback (''Hanging Fire'') and Chris and Cosey (''Silent Cry''); the album starts out bleakly metallic and builds up to Howard Jones's ''Assault and Battery,'' catchy despite lyrics about ''mass torture/all hands to the knife.'' Royalties for the album will be donated to People for the Ethical Treatment of Animals in Washington.