The second richest Kentucky Derby, with perhaps the shortest-priced favorite in the 103-year history of the event, will be offered Saturday at Churchill Downs.

Seattle Slew was entered in the 1-mile classic today along with 14 other 3-year-olds. The opposition apparently is not overly impressed by Slew's perfect streak through six starts. If all 15 start thiss renewal of America's most famous horse race will gross $267,200, with $214,700 to the winner. Cannonade earned $221,500 from a record $274,000 prize in 1974.

Slew is listed at 2 to 5 in most advance betting lines. Calumet's entry of Citation and Coaltown (1948) and Count Fleet (1943) won at 40 cents on the dollar. If Saturday's favorite should drop to 3 to 10 he would be the shortest price in the history of parimutuel betting on the Derby.

The entry of Run Dusty Run and Bob's Dusty, trained by Smiley Adams, in the probable 6-to-1 second choice.

LeRoy Jolley conditions For The Moment, the Blue Grass Stakes victoe which is third, at 8 to 1, in most lines. Jolley saddled Foolish Pleasure to win the 1975 Derby before losing with Honest Pleasure last spring, to Bold Forbes. Laz Barerra, Bold Forbes' trainer, tries with California-based Affiliate this time.