Insects and gut health in food-producing animals

Abstract

Insect meals, oils and live larvae can represent valuable innovative dietary ingredients foranimal nutrition. In particular, Hermetia illucens and Tenebrio molitor are the most promising insect species for animal’s feed. This chapter will focus on the effects of insect-derivedfeed ingredients on gut health of food-producing animals. In poultry low dietary inclusionlevels of insect meal (< 15%) are recommended, as they maintain diet digestibility, guthealth, and, adequate growth performance. In fish and pigs, both low and high inclusionlevels of insect-based products (fish: from 3 to 60%; pigs: from 1.5 to 33%), can efficientlybe used. Insect oils rich in lauric acid with antibacterial activities, seem to be a promisingalternative fat source in rabbit nutrition as they do not impair diet digestibility and growthperformance of the animals, also improving their intestinal microbiota. Less information isavailable on ruminants due to the European ban on the use of processed animal proteins inthis species to avoid the spreading of the bovine spongiform encephalopathy. The availablepreliminary studies have been mainly performed in vitro using 7.5 to 25% of insects in substitution of soybean meal, suggesting that insects may represent a suitable protein and fatsource also for ruminants, especially considering the ability of chitosan to reduce ruminalbiohydrogenation and methane production without impairing diet digestibility. However,further studies are needed to confirm the potential effects of insect meals and oils on guthealth of rabbit and ruminants and to better know the prebiotic/probiotic activity in different food producing animals.