salex,

There is no study that I am aware of that focuses on the relative nutritional properties of LMB prey. There are, however, many investigations into the energy density and nutritional profiles of various organisms. Member ewest pointed me to a paper on Arizona NP growth rates where energy density of various species which comprised the diet of NP in the three lakes under study. The density units are in J/g wet instead of calories. This can serve as starting place into your own investigations.

Species................J/g Wet......Author
===========......======......================
Black crappie........4186..........Kitchell et al. 1974
Bluegill..................4186..........Kitchell et al. 1974
Common carp.......7524..........Cummins and Wuycheck 1971
Golden shiner.......4983..........Kelso 1972
Green sunfish.......4186..........Kitchell et al. 1974
Largemouth Bass..4186.........Rice et al. 1983
Northern crayfish...6153.........Stein and Murphy 1976
Northern pike.........3600.........Bevelheimer et al. 1985
Rainbow trout.........6069.........Rand et al. 1993

(I thought images were working? or still no?)