Levels of insect crude protein and minerals in guano of insectivorous bats

The little brown bat, Myotis lucifugus, is a common inhabitant in many parts of North America and has been a part of this investigation at Wooster, Ohio, since 2006. This insectivore reportedly feeds upon a variety of insect species, especially from aquatic environments, including midges, caddisflies, mayflies, gnats, mosquitoes, and also beetles, wasps, moths, etc. The objective of this investigation is to determine the levels of insect crude protein and total mineral content present in fecal material and urine deposited by these bats at their roosting site. Approximately 453.6 kgs of guano were removed from a roosting site in the belfry of a local church building in 2006. This represented deposits over many years. Bat numbers at this roosting site vary from year to year; however, in recent years, the recorded estimates range from 1775 in 2004 to 1000 in 2008. Subsequently, approximately 6.8 kgs of guano were removed in 2007 and 12.7 kgs in 2008. Samples from the 453.6 kg lot were analyzed for dry matter, crude protein, crude fat and total mineral content. On a 100% dry matter basis, crude protein, analyzed by the Kjeldahl method, yielded 72.76 %; and total mineral content, determined by oxidizing samples in a muffle furnace for four hours at 600^oC, yielded 27.89%. It is suggested crude protein present in bat guano likely represents the indigestible portion of protein bound up in chitin of the insect integument.