I have no expertice (sp?) on this but can you try a food like for racing dogs??..... once I saw the recipe but can´t remember correcly as they need it as a boost..... you might try that as a supplement

it´s mainly raw but includes also some oils and other thing I cna´t recall, sorry i´m not of much help but maybe it´s a hint and you can search and/or ask someone who does that racing/agility......