A variety of invertebrates are commonly fed to insectivorous animals by both zoos and hobbyists, but information as to the nutrient composition of most commercially raised species is limited. Adult house crickets, house cricket nymphs (Acheta domesticus), superworms (Zophobas morio larvae), giant mealworm larvae, mealworm larvae and adult mealworms (Tenebrio molitor), waxworm larvae (Galleria mellonella), and silkworm larvae (Bombyx mori) were analyzed for moisture, crude protein, crude fat, ash, acid detergent fiber (ADF), neutral detergent fiber (NDF), minerals, amino acids, fatty acids, and vitamins. Earthworms (Lumbricus terresstris) were analyzed for moisture, crude protein, crude fat, ash, ADF, NDF, minerals, amino acids, and vitamins A and D 3 . Proximate analyses were variable, with wide ranges found for moisture (57.9-83.6%), crude protein (9.3-23.7%), crude fat (1.6-24.9%), ADF (0.1-7.4%), NDF (0.0-11.5%), and ash (0.6-1.2%). Energy content ranged from a low of 674 kcal/kg for silkworms to 2,741 kcal/kg for waxworms.Using an amino acid scoring pattern for rats, the first limiting amino acid for all invertebrates tested was the total sulfur amino acid methionine+cystine. Deficiencies by nutrient (% of samples deficient vs. NRC requirements for rats on a dry matter (DM) basis) were as follows: calcium (100%), vitamin D 3 (100%), vitamin A (89%), vitamin B 12 (75%), thiamin (63%), vitamin E (50%), iodine (44%), manganese (22%), methioninecystine (22%), and sodium (11%). Deficiencies by invertebrate species (number of nutrients deficient vs. the NRC requirements for rats on a DM basis) were as follows: waxworms (9), superworms (8), giant mealworm larvae (7), adult mealworms (6), mealworm larvae (5), adult house crickets (4), house cricket nymphs (4), silkworms (4), and earthworms (4). These data provide a basis for determining nutrient intake of captive insectivores, and will aid in the development of gut-loading diets to provide captive insectivorous animals with appropriate levels of necessary nutrients. Zoo Biol 21: 269-285, 2002.

A variety of insects are commonly fed to captive insectivores but detailed nutritional analyses are only available for the most commonly fed species. Soldier fly larvae, Turkestan cockroach nymphs, tebo worms, and adult house flies were analyzed for moisture, protein, fat, ash, acid detergent fiber, neutral detergent fiber, minerals, amino acids, fatty acids, vitamins, and selected carotenoids. The acid detergent fiber was analyzed for amino acids to estimate chitin content. Nutrient content varied widely between the four insect species. Ranges for the macronutrients were as follows: moisture (60.2-74.8%), crude protein (15.5-19.7%), crude fat (1.9%-29.4%), acid detergent fiber (1.4-3.0%), neutral detergent fiber (2.6-3.8%), and ash (0.8-3.5%). Energy content ranged from a low of 918 kcal/kg for house flies to 2,977 kcal/kg for tebo worms. The chitin content of these four species ranged from 6.7 to 21.0 mg/kg. The nutrients most likely to be deficient when these species of insects are used as food for insectivores are vitamin A, vitamin D, calcium, vitamin E, thiamine, iodine, and vitamin B(12) . The number of nutrients deficient vs. the NRC requirements for rats on an energy basis by insect species was as follows: soldier fly larvae (3), tebo worms (15), Turkestan cockroach nymphs (5), and adult house flies (6). These data are valuable in helping assess the nutrient intake of captive insectivores and in developing gut-loading diets to improve the nutrient intake of captive insectivores.

Insects contain significant amounts of fiber as measured by crude fiber, acid detergent fiber (ADF) or neutral detergent fiber (NDF). It has always been assumed that the fiber in insects represents chitin based on the structural similarity between cellulose and chitin and the fact that the ADF fraction from insects contains nitrogen. In this study, a number of insect species that are raised commercially as food for insectivores were analyzed for moisture, crude protein (nitrogen x 6.25), fat, ash, NDF, ADF, and amino acids. Additionally, the ADF fraction was analyzed for nitrogen and amino acids to determine if proteins might be present in the ADF fraction. The ADF fraction contained a significant amount of amino acids accounting for 9.3-32.7% of the ADF (by weight). The presence of amino acids in the ADF fraction means that using ADF to estimate insect chitin results in an overestimation of insect chitin content. Using ADF adjusted for its amino acid content, the estimated chitin content of these insect species ranged from 2.7-49.8 mg/kg (as is) and 11.6-137.2 mg/kg (dry matter basis). Additionally, these data suggest that for the species measured here the amount of chitin nitrogen is quite small (as a % of total nitrogen) and that crude protein (nitrogen x 6.25) provides a reasonable estimate of the true protein for most species of insects. Zoo Biol 0:1-11, 2007. (c) 2007 Wiley-Liss, Inc.

Commercially raised feeder insects used to feed captive insectivores are a good source of many nutrients but are deficient in several key nutrients. Current methods used to supplement insects include dusting and gut-loading. Here, we report on the nutrient composition of four species of commercially raised feeder insects fed a special diet to enhance their nutrient content. Crickets, mealworms, superworms, and waxworms were analyzed for moisture, crude protein, fat, ash, acid detergent fiber, total dietary fiber, minerals, amino acids, fatty acids, vitamins, taurine, carotenoids, inositol, and cholesterol. All four species contained enhanced levels of vitamin E and omega 3 fatty acids when compared to previously published data for these species. Crickets, superworms, and mealworms contained b-carotene although using standard conversion factors only crickets and superworms would likely contain sufficient vitamin A activity for most species of insectivores. Waxworms did not contain any detectable b-carotene but did contain zeaxanthin which they likely converted from dietary b-carotene. All four species contained significant amounts of both inositol and cholesterol. Like previous reports all insects were a poor source of calcium and only superworms contained vitamin D above the limit of detection. When compared to the nutrient requirements as established by the NRC for growing rats or poultry, these species were good sources of most other nutrients although the high fat and low moisture content of both waxworms and superworms means when corrected for energy density these two species were deficient in more nutrients than crickets or mealworms. These data show the value of modifying the diet of commercially available insects as they are growing to enhance their nutrient content. They also suggest that for most insectivores properly supplemented lower fat insects such as crickets, or smaller mealworms should form the bulk of the diet. Zoo Biol. 34:554-564, 2015.

Insects are promising feedstuffs for animal feeds as they contain not only valuable nutrients but also particular compounds that seem to be able to modulate animal microbiota and to optimise animal health. So far, there has been little work on the effects of those insect derived compounds in animal feeding trails but initial investigations show promising results. This editorial discuss the effect of chitin, lauric acid, and anti-microbial peptides provided by insects.

This article reports on the nutrients present in insects and factors affecting their variability. Data on protein content and amino acid profiles of a variety of insect species are discussed and their amino acid profiles compared to nutrient requirements of growing broiler chicks, catfish, trout, swine, and human adults and young children. Both in vitro and in vivo protein digestibility data for a variety of insect species is presented and factors affecting these data are discussed. Furthermore, the fat content and fatty acid profiles of a variety of insect species is reviewed, with special attention on omega-6 and omega-3 fatty acids. Information on carbohydrates, fibre and chitin in insects is shown along with potential effects on nutrient availability. This is followed by a discussion of essential minerals in insects with an emphasis on calcium and phosphorus. Data on insect vitamin content is shown along with a discussion of antinutritional factors such as phytate and thiaminase, which can adversely affect their nutritional value. Dietary effects on insect nutrient composition are reviewed with an emphasis on essential minerals, heavy metals, vitamin E, and carotenoids. Lastly, the effects of processing, including protein extraction and various cooking methods on insect composition are discussed. In summary, this article provides an overview of the nutrient content of insects, and how select nutrients can be altered.

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A variety of commercially raised insects are fed to insectivorous reptiles, but information concerning appropriate diets used to feed these insects is limited. In the present study, house crickets (Acheta domesticus adults and nymphs), mealworms (Tenebrio molitor larvae), and silkworms (Bombyx mori larvae) were fed diets containing graded levels of calcium (Ca) and/or vitamin A-nutrients that are low or absent in most insects. Diets and insects were analyzed for moisture, Ca, phosphorus (P), and vitamin A. For adult crickets and cricket nymphs, body Ca and vitamin A concentrations increased in a linear fashion with increasing levels of dietary Ca or vitamin A. Ca concentrations of silkworms also increased in a linear fashion with increasing levels of dietary Ca. For mealworms, body Ca and vitamin A concentrations increased in a nonlinear fashion with increasing levels of dietary Ca or vitamin A. These regression equations, in conjunction with insect nutrient composition, allow for the calculation of the optimum nutrient concentration for gut-loading diets. Final recommendations were based on National Research Council (NRC) requirements for rats, adjustments for the energy content of the insects, and nutrient overages as appropriate. Gut-loading diets for crickets (adults and nymphs) should be supplemented to contain the following nutrients, respectively: Ca (51 and 32 g/kg), vitamin A (8,310 and 5,270 mg retinol/kg), vitamin D (300 and 190 mg cholecalciferol/kg), vitamin E (140 and 140 mg RRR-a-tocopherol/kg), thiamin (31 and 21 mg/kg), and pyridoxine (20 and 10 mg/kg). Gut-loading diets for mealworms should be supplemented to contain the following nutrients: Ca (90 g/kg), iron (51 mg/kg), manganese (31 mg/ kg), vitamin A (13,310 mg retinol/kg), vitamin D (460 mg cholecalciferol/kg), vitamin E (660 mg RRR-a-tocopherol/kg), thiamin (5 mg/kg), vitamin B 12 (650 mg/kg), and methionine (29 g/kg). Gut-loading diets for silkworms should be supplemented to contain the following nutrients: Ca (23 g/kg), iodine (0.7 mg/kg), vitamin D (140 mg cholecalciferol/kg), vitamin E (70 mg RRR-a-tocopherol/kg), and vitamin B 12 (226 mg/kg).