Article

Gut loading to enhance the nutrient content of insects as food for reptiles: A mathematical approach

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Abstract

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 µg retinol/kg), vitamin D (300 and 190 µg cholecalciferol/kg), vitamin E (140 and 140 mg RRR-α-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 µg retinol/kg), vitamin D (460 µg cholecalciferol/kg), vitamin E (660 mg RRR-α-tocopherol/kg), thiamin (5 mg/kg), vitamin B12 (650 µg/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 µg cholecalciferol/kg), vitamin E (70 mg RRR-α-tocopherol/kg), and vitamin B12 (226 µg/kg).

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... Calcium levels are typically less than 0.3% dry matter (Barker et al., 1998;Finke, 2002Finke, , 2013Oonincx and van der Poel, 2011;Oonincx and Dierenfeld, 2012;Punzo, 2003). The higher levels of calcium occasionally reported for feeder crickets likely reflect calcium in the gut contents (Barker et al., 1998;Finke, 2003;Hatt et al., 2003;Punzo, 2003). The exoskeleton of most insects is primarily composed of protein and chitin, although some insects have a mineralized exoskeleton in which calcium and other minerals are incorporated into the cuticle (Dashefsky et al., 1976). ...
... Because the contents of the gastrointestinal tract can represent a significant percentage of the total weight of the insect (Finke, 2003), it can have a significant effect on the mineral content of the insect if it is analyzed when fully fed. Additionally studies of wild insects show both seasonal variation as well as variation between different populations of the same species living in the same general area (Finke, 1984;Studier et al., 1991;Studier and Sevick, 1992). ...
... The same powder used for pinhead or adult house crickets could therefore have different effects on their chemical composition (Sullivan et al., 2009). Similarly, for gut-loaded insects, size differences could lead to differences in nutrient delivery of smaller versus larger insects (Finke, 2003(Finke, , 2005. ...
Chapter
A variety of insects are commonly fed to captive insectivores. We review the nutrient content of a variety of commercially raised insects and compare those values to the data available for wild insects. These data are discussed in light of the nutrient requirements for domestic animals to identify nutrients of concern for captive insectivores. Additionally, various environmental and dietary factors that can significantly affect insect nutrient composition are reviewed. We then evaluate the various techniques that are currently used to enhance the nutrient content of commercially bred insects, including gut loading and dusting. Lastly, possible negative considerations that might be important factors when feeding captive insectivores, including pathogens, pathogenic microorganisms, toxins, and antinutritional factors, are discussed.
... Initial gut-loading diets focused on correcting the calcium content of insect prey to prevent calcium deficiencies (Allen & Oftedal, 1989;Livingston et al., 2014). The method has been documented to be successful with adult and nymphal crickets and indicates that a successfully ingested gut-loading diet will result in a period of peak nutrient concentration, during which the insect is intended to be offered as prey (Finke, 2003;Livingston et al., 2014). These studies resulted in industry guidelines to deliver adequate amounts of calcium (Allen & Oftedal, 1989, Finke, 2003Ferrie et al., 2014;Livingston et al., 2014). ...
... The method has been documented to be successful with adult and nymphal crickets and indicates that a successfully ingested gut-loading diet will result in a period of peak nutrient concentration, during which the insect is intended to be offered as prey (Finke, 2003;Livingston et al., 2014). These studies resulted in industry guidelines to deliver adequate amounts of calcium (Allen & Oftedal, 1989, Finke, 2003Ferrie et al., 2014;Livingston et al., 2014). ...
... A supplemented diet intended to "gut-load" feeder insects contains highly concentrated nutrients that, when consumed and contained within the insect gastrointestinal tract, may deliver select nutrients in a quantity projected to meet the requirement of the target species (Finke, 2003;Livingston et al., 2014). ...
Article
Captive insectivores may consume invertebrates as all, or part of their overall diet. The challenge with feeding captive insectivores involves the limited number of invertebrate species that are commercially available, and the lack of key nutrients provided by these insects. Among these insects, a naturally occurring low concentration of calcium and an inverse calcium to phosphorus ratio may put insectivores at the risk of developing hypocalcemia. A strategy to correct this nutrient imbalance involves supplementing the insect diet with high concentrations of targeted nutrients – a term referred to as gut-loading. Current industry guidelines recommend feeding a supplemented diet for 48 to 72 h before offering the insect to an insectivore. In the present study, the mineral profile of adult crickets (Acheta domesticus) offered a maintenance diet (1.58% Ca, DMB) are compared to crickets offered a supplemented diet (11.32% Ca, DMB) over 120 h. The supplemented diet produced a cricket with significantly higher calcium concentration compared to the maintenance diet. The calcium concentration of crickets offered the supplemented diet was highest at 48 h (0.63%), but did not achieve a 1:1 Ca:P ratio nor meet the lowest reported nutrient requirements of carnivorous reptiles, omnivorous reptiles, or an insectivorous bird at various life stages. Although the supplemented diet improved the whole body calcium concentration in feeder crickets, the crickets do not provide adequate calcium, iron, or manganese to meet the requirement of insectivores. As evidenced by the current study, the supplemented crickets are not recommended to serve as the sole source of nutrition for an insectivore.
... However, dusting can provide variable results because the amounts adhered to the insects and the change in palatability might affect the overall intake of the supplemented nutrients. 19 Gut loading is considered a more effective method to increase the nutritional balance of feeder insects offered to insectivorous reptiles. 19 By offering a nutrient dense diets to feeder insects, the diet will be retained in the insects' gastrointestinal tract and then be ingested by reptiles. ...
... 19 Gut loading is considered a more effective method to increase the nutritional balance of feeder insects offered to insectivorous reptiles. 19 By offering a nutrient dense diets to feeder insects, the diet will be retained in the insects' gastrointestinal tract and then be ingested by reptiles. In crickets, feeding diets containing different levels of calcium resulted in a linear increase of calcium content in the crickets. ...
... In crickets, feeding diets containing different levels of calcium resulted in a linear increase of calcium content in the crickets. 19 Guidelines for nutrient concentrations required for gut-loading formulas for various invertebrate diets are available. 19 Several highly palatable and nutritionally balanced invertebrate diets (eg, Orange Cube Complete Cricket Diet, Fluker Farms, Port Allen, LA) are readily available and provide a source of hydration as well as critical nutrients, leading to improved nutritional values of gut-loaded feeder insects. ...
Article
Nutritional disorders of captive reptiles remain very common despite the increasing knowledge about reptile husbandry and nutrition. Many nutritional disorders are diagnosed late in the disease process; often secondary complications, such as pathologic fractures in reptiles suffering from nutritional secondary hyperparathyroidism have occurred. Therefore, every attempt should be made to educate reptile owners and keepers about the proper care and dietary needs of reptiles under their care because all nutritional disorders seen in captive reptiles are preventable.
... Several studies have confirmed that the dusting method is an unreliable method to maximize calcium and mineral intake because mineral attachment can vary based on insect grooming behavior. [79][80][81][82] It may also decrease prey consumption because of changes in palatability. Bilby and Widdowson 83 first recognized the correlation of calcium content in earthworms and the calcium composition in blackbirds and thrushes that consumed said earthworms attained from nearby chalky soil. ...
... Several studies have demonstrated that the calcium content of the insect's gut could be measurably altered by its diet. 2,[49][50][51][55][56][57]59,61,[82][83][84][85][86][87] Today, the term gut-loading has come to mean improving the overall vitamin and mineral nutritive profile of insect prey. 43,82,84,85,88 Calcium Supplementation ...
... 2,[49][50][51][55][56][57]59,61,[82][83][84][85][86][87] Today, the term gut-loading has come to mean improving the overall vitamin and mineral nutritive profile of insect prey. 43,82,84,85,88 Calcium Supplementation ...
Article
The study of amphibian nutrition requires a detailed review of species-specific natural prey analysis. Invertebrate nutrient composition has been formally studied for more than 60 years and presents the following conclusions: (1) in general, insects are poor in overall calcium content; (2) larval insects have high fat and protein components; and (3) altering the gut contents of some insects can improve their overall nutritive quality. The fat-soluble vitamin profile for most inverts is lacking. There are new guidelines for calcium and vitamin A supplementation that can help augment invertebrate nutrient profiles to match the minimum NRC requirements established for rats.
... Calcium and phosphorus (P) was the subject of most early supplementation studies and reviews [Allen andOftedal, 1982, 1989;Sabatini et al., 1998;McClements et al., 2003] while other researchers began to evaluate concentrations of vitamins such as A and E in crickets [Pennino et al., 1991;Barker et al., 1998;Sabatini et al., 1998;Attard, 2013]. Later studies investigated concentrations of retinol, retinal, and ß-carotene [Dierenfeld et al., 1995;Finke, 2003;Li et al., 2009;Ogilvy et al., 2011;Sullivan et al., 2012;Attard, 2013]. Regardless of the nutrient under investigation, inconsistencies in the efficacy of supplementation methods are reported [Hunt Coslik et al., 2009;Sullivan et al., 2009;Attard, 2013], with multiple theories of causation and suggestions for mitigation through continued research [Anderson, 2000;Hunt et al., 2001;Finke, 2003;McClements et al., 2003;Sullivan et al., 2009Sullivan et al., , 2012Attard, 2013]. ...
... Later studies investigated concentrations of retinol, retinal, and ß-carotene [Dierenfeld et al., 1995;Finke, 2003;Li et al., 2009;Ogilvy et al., 2011;Sullivan et al., 2012;Attard, 2013]. Regardless of the nutrient under investigation, inconsistencies in the efficacy of supplementation methods are reported [Hunt Coslik et al., 2009;Sullivan et al., 2009;Attard, 2013], with multiple theories of causation and suggestions for mitigation through continued research [Anderson, 2000;Hunt et al., 2001;Finke, 2003;McClements et al., 2003;Sullivan et al., 2009Sullivan et al., , 2012Attard, 2013]. ...
... Insects of the same species often show different nutrient concentration related to variations in these factors [Allen andOftedal, 1982, 1989;Attard, 2013]. In general, insect species, including crickets, contain inadequate levels of calcium and several other nutrients (including vitamin A) required by the animals to which they are fed [Allen and Oftedal, 1982;Bernard and Allen, 1997;Barker et al., 1998;Anderson, 2000;Finke, 2003;Finke et al., 2005;Hunt Coslik et al., 2009;Attard, 2013] As such, the challenge becomes finding a way to provide the insectivore a diet that has the potential to meet all of their (known or assumed) nutritional requirements. ...
Article
Over the last 25 years, numerous studies have investigated the impact of insect supplementation on insect nutrient content. In light of recent nutrition related challenges with regards to zoo amphibians fed an insect based diet, this review attempts to comprehensively compile both anecdotal and published data in the context of practical application on this topic. Insects, primarily crickets, used for amphibian diets historically demonstrate low concentrations of key nutrients including calcium and vitamin A. Commonly used practices for supplementation involving powder dusting or gut loading have been shown to improve delivery of calcium and vitamin A, though often not reaching desired nutrient concentrations. The large variety of factors influencing insect nutrient content are difficult to control, making study design, and results often inconsistent. Formulation and availability of more effective gut loading diets, combined with a standardized protocol for insect husbandry and dietary management may be the most effective way to supplement insects for use in amphibian feeding programs. Ideally, the nutritional improvement of feeder insects would begin at the breeder level; however, until this becomes a viable choice, we confirm that supplementation of crickets through both gut-loading and dusting appear necessary to support the nutritional health of amphibians and other insectivores in managed collections. Zoo Biol. XX:XX–XX, 2014. © 2014 Wiley Periodicals, Inc.
... Calcium levels are typically less than 0.3% dry matter (Barker et al., 1998; Finke, 2002, 2013; Oonincx and van der Poel, 2011; Oonincx and Dierenfeld, 2012; Punzo, 2003). The higher levels of calcium occasionally reported for feeder crickets likely reflect calcium in the gut contents (Barker et al., 1998; Finke, 2003; Hatt et al., 2003; Punzo, 2003). The exoskeleton of most insects is primarily composed of protein and chitin, although some insects have a mineralized exoskeleton in which calcium and other minerals are incorporated into the cuticle (Dashefsky et al., 1976). ...
... Although butterworm larvae did not contain any selenium, the other 11 species of feeder insects contain selenium at levels ranging from 0.27 to 0.97 mg/kg dry matter (Finke, 2002, 2013). Because the contents of the gastrointestinal tract can represent a significant percentage of the total weight of the insect (Finke, 2003), it can have a significant effect on the mineral content of the insect if it is analyzed when fully fed. Additionally studies of wild insects show both seasonal variation as well as variation between different populations of the same species living in the same general area (Finke, 1984; Studier et al., 1991; Studier and Sevick, 1992). ...
... The same powder used for pinhead or adult house crickets could therefore have different effects on their chemical composition (Sullivan et al., 2009). Similarly, for gut-loaded insects, size differences could lead to differences in nutrient delivery of smaller versus larger insects (Finke, 2003, 2005). ...
... While Butterworm larvae did not contain any selenium the other eleven species of feeder insects contain selenium at levels ranging from 0.27 to 0.97 mg/kg dry matter (Finke 2002;Finke 2013). Since the contents of the gastrointestinal tract can represent a significant percentage of the total weight of the insect (Finke 2003), it can have a significant effect on the mineral content of the insect if it is analysed when fully fed. Additionally studies of wild insects show both seasonal variation as well as variation between different populations of the same species living in the same general area (Finke 1984;Studier et al. 1991). ...
... The same powder used for pinhead or adult House crickets could therefore have different effects on their chemical composition (Sullivan, Livingston et al. 2009). Similarly for gut loaded insects size differences could lead to differences in nutrient delivery of smaller versus larger insects (Finke 2003;Finke 2005). ...
... Most research on the effects of gut loading has focused on increasing the calcium content of insects. High calcium diets containing 4-9% calcium, typically from calcium carbonate, have proven effective in increasing the calcium content of wax moth larvae, House crickets, Yellow mealworm larvae and silkworm larvae (Strzelewicz, Ullrey et al. 1985;Allen and Oftedal 1989;Bernard et al. 1997;Anderson 2000;Klasing, Thacker et al. 2000;Finke 2003;Finke, Dunham et al. 2005). Chemical analysis of the diet provided might be necessary to verify the true calcium content of commercially available gut-loading diets . ...
... However, most feeder invertebrates are a poor source of select macro-minerals and vitamins, such as calcium and fat-soluble vitamins (A, D and E), consequently leading to deficiencies and nutritional disorders. Disorders frequently seen include metabolic bone disorder (MBD), malnutrition and hypovitaminosis A, D and E (Barker et al. 1998;Dierenfeld 1989;Klasing et al. 2000;Finke 2002Finke , 2003Hernandez-Divers 2006;Michaels et al. 2014). Nutritional deficiencies that are left unaddressed can lead to muscular and neurological dysfunction, poor growth and poor reproductive success (Allen et al. 1993;Bernard et al. 1997;Anderson 2000;Finke 2002;Dierenfeld and Fidgett 2003;McWilliams 2005;Donoghue 2005; Vaughan and Browne 2009). ...
... Nutritional disorders have not been documented in insectivores in situ. This has been attributed to the variety of invertebrate prey species available to free-ranging insectivores, the variability of the prey's diet, and the predator's ability to self-supplement (McClements et al. 2003;Finke 2003Finke , 2013Finke and Winn 2004;Ogilvy et al. 2012;Allen et al. 1993). Insectivores have been reported to exhibit self-supplementation in the form of geophagy and coprophagy. ...
... Nutritional deficiencies in insectivores can be successfully prevented or at least minimised using a variety of techniques, with the two most common involving either the dusting of prey with a multi-vitamin and mineral powder, and/or gut loading invertebrate prey (Bernard et al. 1997;Anderson 2000;Hunt et al. 2001;Finke 2003;Michaels et al. 2014). Dusting typically requires the prey to be fed immediately after dusting (McClements et al. 2003) since the powder is thought to fall off due to invertebrate movements, as well as being actively removed by grooming (Michaels et al. 2014). ...
Article
Full-text available
Techniques for increasing the nutritional value of feeder invertebrates include dusting the prey items with a vitamin and mineral powder supplement, or providing the invertebrates with nutrient-rich food, called gut loading, prior to feeding to insectivores. However, the delay between gut loading of prey and consumption by insectivores varies according to feeding regime and may be considerable if prey is left in the vivarium. This study aimed to determine the effect of time post gut loading on the nutritional composition of three species of invertebrates, mealworms (Tenebrio molitor larvae, approximately 23–30 mm), giant African land snails (Achatina fulica, shell size 10–35 mm) and dubia cockroaches (Blaptica dubia, approximately 20–30 mm). Feeder invertebrates were maintained on a dry commercial gut-loading diet, supplemented with fresh vegetables for 48 hours, after which the diet was removed. Samples of invertebrates (120 g of mealworms, 80 g of snails and 100 g of cockroaches) were taken for proximate analysis (dry matter, ash, crude fat and crude protein) at 0.5 h (excluding cockroaches), 1 h, 6 h and 12 h (excluding snails) using standard laboratory procedures. A one-way analysis of variance was performed to test for differences in nutrient content between time points in each species. Crude protein and fat contents of snails were significantly greater at 6 h compared to 0 h (P < 0.01). However, no other significant differences in nutrient content of snails or other species were detected at any time points. It is feasible that the increases in crude protein and fat of snails were a result of nutrient accumulation within the body. These findings indicate that in the species tested, with the exception of snails, delays of up to 12 hours between gut loading of the prey and their consumption by a carnivore are unlikely to affect the concentrations of macro-nutrients (protein, fat, dry matter and ash).
... When these diets are used to gut load crickets factors other than diet calcium can also affect cricket calcium content. These factors include diet palatability, diet particle size, and the size of the cricket (Allen and Oftedal, 1989, Anderson, 2000, Hunt, et al, 2001, Finke 2003, Winn, et al, 2003. As such, a simple analysis of dietary calcium may not be effective in predicting cricket calcium content. ...
... Treatments-The experiment consisted of six treatments (Table 1). Treatment 1 has previously been shown to result in crickets that contain sufficient calcium for insectivorous reptiles and thus served as a positive control, while treatment 2 served as a negative control (Finke, 2003, Finke, et al, 2004. Treatments 3 through 6 were four commercial gut loading diets labeled for use with crickets. ...
... Food Sources-The diet for treatment 1 was Timberline Cricket Power Food mixed with 15% calcium carbonate (HuberCal, JM Huber Corporation, Edison, NJ) to achieve an estimated 65 g Ca/kg diet (Finke, 2003, Finke, et al, 2004. The diet for treatment 2 was Timberline Cricket Power Food (a diet designed for cricket growth and reproduction) without any additional supplementation. ...
... Earthworms (Lumbricus terresstris) are also commonly gathered for food. Nutritional information for these species and others is summarized in Tables 1-3 (original sources are Barker et al. 1998, Bernard and Allen 1997, Finke 2002, Finke 2005, Pennino et al. 1991. In order to facilitate comparisons between different papers, all these data have been recalculated from the original data to express the information on an as-is rather than dry-matter basis, because most insects are fed live (with the moisture they naturally contain). ...
... Earthworms (Lumbricus terresstris) are also commonly gathered for food. Nutritional information for these species and others is summarized in Tables 1-3 (original sources are Barker et al. 1998, Bernard and Allen 1997, Finke 2002, Finke 2005, Pennino et al. 1991. In order to facilitate comparisons between different papers, all these data have been recalculated from the original data to express the information on an as-is rather than dry-matter basis, because most insects are fed live (with the moisture they naturally contain). ...
... The life stage and any additional information on how the insect was reared or the food used are also shown in Table 1. More comprehensive reviews of the nutrient content of a wider range of insects are available (Bukkens 1997, Finke 2004. ...
Article
Insects are an important food source for numerous animals. Although insects are a good source of many nutrients, they are deficient in several others; therefore, providing adequate nutrition for insectivores in rehabilitation can be challenging. This paper presents an overview of insects' nutrient composition. The authors also analyze and discuss various strategies for supplementing cultured insects and creating insect-substitute foodstuffs. Guidelines for evaluating insectivore diets are recommended.
... Calcium levels are typically less than 0.3% dry matter (Barker et al., 1998;Finke, 2002Finke, , 2013Oonincx and van der Poel, 2011;Oonincx and Dierenfeld, 2012;Punzo, 2003). The higher levels of calcium occasionally reported for feeder crickets likely reflect calcium in the gut contents (Barker et al., 1998;Finke, 2003;Hatt et al., 2003;Punzo, 2003). The exoskeleton of most insects is primarily composed of protein and chitin, although some insects have a mineralized exoskeleton in which calcium and other minerals are incorporated into the cuticle (Dashefsky et al., 1976). ...
... Because the contents of the gastrointestinal tract can represent a significant percentage of the total weight of the insect (Finke, 2003), it can have a significant effect on the mineral content of the insect if it is analyzed when fully fed. Additionally studies of wild insects show both seasonal variation as well as variation between different populations of the same species living in the same general area (Finke, 1984;Studier et al., 1991;Studier and Sevick, 1992). ...
... The same powder used for pinhead or adult house crickets could therefore have different effects on their chemical composition (Sullivan et al., 2009). Similarly, for gut-loaded insects, size differences could lead to differences in nutrient delivery of smaller versus larger insects (Finke, 2003(Finke, , 2005. ...
... Most studies have evaluated dietary supplementation with calcium in domestic crickets (Acheta domesticus), 10,14,18,30,a mealworms (T molitor), 9,11,12,14 and, to a lesser extent, domestic flies (Drosophila melanogaster), 18 waxworms (Galleria mellonella), 15 and silkworms (Bombyx mori). 8 Insects that have a naturally high calcium content include larvae of the black soldier fly (Hermetia illucens) 31,32 and adult wood lice (Porcellio scaber). 26 Since dietary supplementation with high mineral content can be toxic to insects, calciumenriched substrates have been evaluated for optimal intake by insects. ...
... It is possible that fasting for 48 hours is not required to ensure maximal trial dietary intake. The findings of the present study complimented the findings of studies 8,11,12 that examined dietary intake of unfasted mealworms and crickets exposed to various high-calcium food substrates. It is important to note that previous studies 8,11,12 on intestinal loading have confirmed that 48 hours is a sufficient period for mealworms to maximize their calcium content when fed a high-calcium diet. ...
... This time interval reflects anticipated high-food intake by the insects, as most are starved and dehydrated from prior transport. Although not evaluated in the present study, other studies 8,11,14 have revealed that increases in nutritive quality of mealworms occur as early as 24 hours after a diet is offered. ...
Article
OBJECTIVE To evaluate whether the nutritive quality of Tenebrio molitor larvae and Zophobas morio larvae, which are commonly cultured as live food sources, is influenced by 4 commercially available diets used as nutritional substrates; identify which diet best improved calcium content of larvae; and identify the feeding time interval that assured the highest calcium intake by larvae. ANIMALS 2,000 Zophobas morio larvae (ie, superworms) and 7,500 Tenebrio molitor larvae (ie, mealworms). PROCEDURES Larvae were placed in control and diet treatment groups for 2-, 7-, and 10-day intervals. Treatment diets were as follows: wheat millings, avian hand feeding formula, organic avian mash diet, and a high-calcium cricket feed. Control groups received water only. After treatment, larvae were flash-frozen live with liquid nitrogen in preparation for complete proximate and mineral analyses. Analyses for the 2-day treatment group were performed in triplicate. RESULTS The nutrient composition of the high-calcium cricket feed groups had significant changes in calcium content, phosphorus content, and metabolizable energy at the 2-day interval, compared with other treatment groups, for both mealworms and superworms. Calcium content and calcium-to-phosphorus ratios for larvae in the high-calcium cricket feed group were the highest among the diet treatments for all treatment intervals and for both larval species. CONCLUSIONS AND CLINICAL RELEVANCE A 2-day interval with the high-calcium cricket feed achieved a larval nutrient composition sufficient to meet National Research Council dietary calcium recommendations for nonlactating rats. Mealworm calcium composition reached 2,420 g/1,000 kcal at 48 hours, and superworm calcium composition reached 2,070g/1,000 kcal at 48 hours. These findings may enable pet owners, veterinarians, insect breeders, and zoo curators to optimize nutritive content of larvae fed to insectivorous animals.
... Calcium levels are typically less than 0.3% dry matter ( Barker et al., 1998;Finke, 2002Finke, , 2013; Oonincx and van der Poel, 2011;Oonincx and Dierenfeld, 2012;Punzo, 2003). The higher levels of calcium occasionally reported for feeder crickets likely reflect calcium in the gut contents ( Barker et al., 1998;Finke, 2003;Hatt et al., 2003;Punzo, 2003). The exoskeleton of most insects is primarily composed of protein and chitin, although some insects have a mineralized exoskeleton in which calcium and other minerals are incorporated into the cuticle ( Dashefsky et al., 1976). ...
... Although butterworm larvae did not contain any selenium, the other 11 species of feeder insects contain selenium at levels ranging from 0.27 to 0.97 mg/kg dry matter ( Finke, 2002Finke, , 2013). Because the contents of the gastrointestinal tract can represent a significant percentage of the total weight of the insect ( Finke, 2003), it can have a significant effect on the mineral content of the insect if it is analyzed when fully fed. Additionally studies of wild insects show both seasonal variation as well as variation between different populations of the same species living in the same general area ( Finke, 1984;Studier et al., 1991;Studier and Sevick, 1992). ...
... The same powder used for pinhead or adult house crickets could therefore have different effects on their chemical composition ( Sullivan et al., 2009). Similarly, for gut-loaded insects, size differences could lead to differences in nutrient delivery of smaller versus larger insects ( Finke, 2003Finke, , 2005). ...
... Nutritional secondary hyperparathyroidism and hypovitaminosis A are two of the most common nutritional disorders being managed in a clinical setting (Mans & Braun, 2014). Nutritional analyses have been performed on a majority of the insects commercially raised for food, and while these analyses have shown that insects provide an excellent source of most nutrients, they are usually deficient in calcium, fat-soluble vitamins (A, D, and E), thiamine, and omega 3-fatty acids (Finke, 2002(Finke, , 2003(Finke, , 2013. To correct these deficiencies, veterinarians, nutritionists, and herpetoculturists have employed two strategies to improve the insect's nutritional quality: dusting and gut loading. ...
... While these insects are mineral-dense, they are, unfortunately, still deficient in fat-soluble vitamins. Most nutritional requirements are currently unknown for reptiles and amphibians, but recommendations are often based on the known requirements in other species (Ferguson et al., 1996;Finke, 2003;Hoby et al., 2010;Latney & Clayton, 2014;Livingston et al., 2014). ...
... Multiple studies have been performed assessing the efficacy of gut-loading vitamin A into crickets and mealworms, but there is currently no published data regarding the efficacy or feasibility of gut-loading BSF larvae for food use in insectivore species (Allen, 1997;Attard, 2013;Finke, 2003;Hunt Coslik et al., 2009;Li et al., 2009;Livingston et al., 2014). Although BSF larvae are a relatively new addition to the exotic pet food market, they have been well studied in the fields of entomology and livestock production (Barragan-Fonseca et al., 2017;Bondari & Sheppard, 1981;Cammack & Tomberlin, 2017;Diener et al., 2009;Hale, 1973;Holmes et al., 2016;Newton et al., 1977;Sheppard et al., 2002;Tomberlin et al., 2009Tomberlin et al., , 2002. ...
Article
Black soldier fly (BSF) larvae are potentially an excellent source of calcium for insectivores; however, previous studies have identified that they lack appreciable amounts of fat‐soluble vitamins (A, D3, and E). To make BSF larvae a more complete food item, fat‐soluble vitamins should either be provided via gut loading or with a multivitamin dusting supplement. The purpose of this study is to identify factors associated with gut loading vitamin A into BSF larvae and to develop feeding recommendations for a more consistent gut‐loading process. Factors that were addressed include the vitamin A concentration added to the diet, length of time given to gut load, moisture content of the diet, and density of larvae during feeding. Diets and larvae were analyzed for vitamin A concentration using high‐performance liquid chromatography. Larval vitamin A concentrations increased in a nonlinear fashion with increasing dietary vitamin A. Length of time (F = 150.818, p < .001), moisture content of the diet (F = 41.436, p < .001), and larval density (F = 78.407, p < .001) were all found to be significant factors contributing to the larvae's gut‐loading capacity. On the basis of our results and vitamin A recommendations from the National Resource Council for rats and poultry, gut‐loading recommendations for BSF larvae when fed to insectivorous reptiles and amphibians are as follows: vitamin A concentration of diet between 16,000 and 20,000 mcg retinol equivalents/kg, gut‐loading time period of 24 h, moisture content of the diet approximately 60%, and larval density between 0.1 and 1 larvae per each gram of moist substrate. Research Highlights • Black soldier fly larvae gut‐loading diets should be moist, plentiful, and offered for no more than 24 h. • Gut‐loading diets should consist of at least 16,000 mcg/kg vitamin A to reach appropriate larval concentrations.
... domesticus), the gut content represents approximately 5% of the body weight. Therefore, by not fasting these animals, they were gutloaded, which likely impacted the nutrient compositions reported (Boyer & Scott, 2019;Clayton, 2014;Finke, 2003;Fledelius et al., 2005). Since the gut contents are a small percentage of the total insect weight, we do expect that the trace minerals noted in Table 4 are more affected by gut loading than the proximate analyses in Table 2. ...
... All species had Ca to P ratios less than 1:1 in this study. For many insectivores, a dietary Ca:P ratio of 1.5 to 2:1 is recommended, thus confirming the need for dietary calcium supplementation and gut-loading before consumption to augment the nutritional content of feeder insects (Boyer & Scott, 2019;Clayton, 2014;Finke, 2003;Fledelius et al., 2005). Further research is necessary to determine appropriate supplementation regimens to add to the diet of insectivores to achieve the recommended Ca:P ratios using these cockroach species. ...
... Furthermore, this data forms a baseline for maintenance diets to improve the nutritional content of these invertebrates when fed to insectivorous reptiles, amphibians, birds, and mammals that are managed in human care. Previous research in insect diets have largely focused on calcium supplementation, with limited studies on other nutrients (Allen & Oftedal, 1989;Anderson, 2000;Ferguson et al., 1996;Finke, 2003;Hoby et al., 2010;Klasing et al., 2000). This study underscores the differences in nutrient content with respect to life stage, sex, and species in novel species of feeder insects. ...
Article
A variety of insects are fed to insectivorous animals; however, nutritional analyses are often limited to adult life stages. Four species of nymph and adult female and male cockroaches (Blaberus giganteus, Blaptica dubia, Blatta lateralis, and Gromphadorhina portentosa) were analyzed for moisture, crude protein (CP), acid detergent fiber (ADF), fat, ash, and mineral content. The small sample size of this study precluded statistical analyses, however comparatively, CP in adult B. lateralis and B. dubia was greater than the CP in nymphs of the same species. Adult and nymph B. dubia had the greatest CP (96.6% and 65.3%, respectively) compared to the other three species. Inversely, fat content in adult B. lateralis and B. dubia was lower than that of nymphs of the same species. All adults contained similar levels of ADF, yet adult B. giganteus had greater ADF than nymphs; conversely, B. lateralis and B. dubia adults had less ADF than nymphs. There were differences noted in mineral parameters among the four species and life stages. Adult B. giganteus had less Ca than G. portentosa, and the lowest Ca content of the four species of nymphs and adults analyzed. This study underscores the differences in nutrient content with respect to life stage and species in previously understudied cockroaches to improve nutrient intake in captive insectivores. HIGHLIGHTS • Some species of adult cockroaches had comparatively lower fat, higher crude protein, and Ca compared to nymphs, and demonstrated interspecies differences in nutrient profiles; these results can be used to assist in diet formulation for insectivores.
... In addition to NSHP, hypovitaminosis A is another common condition associated with insectivorous reptiles [9,10]. Most feeder insects, including BSF larvae, are severely deficient in the fat soluble vitamins (A, D 3 , and E), and thus still require multivitamin dusting or gut loading [3,[11][12][13]; however, recent research has found that some insects can produce vitamins D 2 and D 3 secondary to ultraviolet B radiation exposure, similar to vertebrates [14]. Vitamin A is integral to many bodily functions, including growth and development, immunity, vision, reproduction, and health and function of glands, ducts, and mucous membranes [10,[15][16][17]. ...
... Vitamin A is integral to many bodily functions, including growth and development, immunity, vision, reproduction, and health and function of glands, ducts, and mucous membranes [10,[15][16][17]. Although true requirements for vitamins are not known for any reptile species, generic recommendations are currently extrapolated from requirements of laboratory rats [12,18]. Previous research from the authors has proved the feasibility of gut loading vitamin A into BSF larvae [1], but determination of reptile digestibility and absorption requires further study. ...
Article
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Black soldier fly (BSF) larvae have been marketed as an excellent choice for providing calcium to reptiles without the need of dusting or gut loading. However, previous studies have indicated that they have limited calcium digestibility and are deficient in fat soluble vitamins (A, D3, and E). In this feeding and digestibility trial, 24 adult male leopard geckos were fed one of three diets for 4 months: 1) whole, vitamin A gut loaded larvae; 2) needle pierced, vitamin A gut loaded larvae; or 3) whole, non-gut loaded larvae. Fecal output from the geckos was collected daily and apparent digestibility was calculated for dry matter, protein, fat, and minerals. There were no differences in digestibility coefficients among groups. Most nutrients were well digested by the leopard geckos when compared to previous studies, with the exception of calcium (digestibility co-efficient 43%), as the calcium-rich exoskeleton usually remained intact after passage through the GI tract. Biochemistry profiles revealed possible deficits occurring over time for calcium, sodium, and total protein. In regards to vitamin A digestibility, plasma and liver vitamin A concentrations were significantly higher in the supplemented groups (plasma- gut loaded groups: 33.38 ± 7.11 ng/ml, control group: 25.8 ± 6.72 ng/ml, t = 1.906, p = 0.04; liver- gut loaded groups: 28.67 ± 18.90 μg/g, control group: 14.13 ± 7.41 μg/g, t = 1.951, p = 0.03). While leopard geckos are able to digest most of the nutrients provided by BSF larvae, including those that have been gut loaded, more research needs to be performed to assess whether or not they provide adequate calcium in their non-supplemented form.
... Calcium (and phosphorus) requirements of amphibians are also under-researched, particularly in conjunction with UVR provision. Feeder insects provided to captive herptiles are of notoriously poor quality with respect to mineral content and inverse Ca:P ratios, which can induce the release of parathyroid hormone and subsequent bone degradation (Sax 2001;Finke 2002;Finke 2003;Campbell 2008). Correct dietary Ca:P ratios vary according to species and requirements, but for most animals it lies between 1:1 and 2:1 (Wise et al. 1963;Fledelius et al. 2005). ...
... Correct dietary Ca:P ratios vary according to species and requirements, but for most animals it lies between 1:1 and 2:1 (Wise et al. 1963;Fledelius et al. 2005). "Gut loading" feeder insects on a fortified diet prior to feeding to insectivores can improve the nutritional quality and, if the diet contains calcium, correct inverse Ca:P ratios (Finke 2002;Finke 2003). Allen et al. (1993) found no significant differences in whole-carcass calcium content of Cuban tree frogs (Osteopilus septentrionalis) fed on "low" calcium (1.2%) and "high" calcium (8.2%) gut-loading diets, although even those fed the high calcium diet contained approximately 25% less calcium in comparison to wild frogs, indicating neither diet was sufficiently high. ...
Article
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In response to global amphibian declines and extinctions, the IUCN has recommended the establishment of ex situ conservation breeding programmes. However, there are a limited number of studies that scientifically assess amphibian husbandry practices, even at a basic level of nutrition and lighting. One component of captive husbandry that is increasingly discussed is the provision of ultraviolet radiation (UVR), which is required for the synthesis of vitamin D 3 and subsequent assimilation of calcium and phosphorous from the diet. Here we used two methods of UV provision ("background UV" and "background UV with UV boost") and two calcium gut-loading diets (5% and 10%) to assess the effects on a range of fitness measures in the red-eyed tree frog (Agalychnis callidryas). We found no effects of either UV treatment or calcium diet on growth, body condition or cutaneous bacterial communities of frogs, although subsequent to the UV boost, frogs had a significantly greater fungal load in comparison to frogs that were not UV-boosted. There were negligible differences in the breeding success of females according to UV exposure. Provision of the UV boost was not demonstrated to provide any real advantages for A. callidryas in terms of growth or breeding success. In addition, there were no benefits of a 10% calcium diet over a 5% calcium diet (in conjunction with regular dusting). Further studies that investigate the UV requirements of other amphibian species and ecotypes are required, particularly in conjunction with naturalistic cricket gut-loading diets.
... As for calcium to phosphorus ratios, mealworms from both gut loading time periods were found to have positive ratios. Previous literature suggests that mealworm gut loading diets should contain 80-90 g of elemental calcium per 1 kg of diet to ensure mealworms reach a positive Ca:P ratio (Klasing et al., 2000;Finke, 2003). The analyzed calcium content of this diet was found to be equivalent to 88 g calcium/kg of diet (Table 2), placing this diet within the recommended values. ...
... Although not measured in this particular study, fat soluble vitamins (A, D 3 , and E) are often the next most common nutrients of concern for feeder insects (Finke, 2002(Finke, , 2003. It is well known that vitamin D 3 plays a vital role in the ability of vertebrate animals to absorb calcium from the gastrointestinal tract (McWilliams, 2005;Boyer and Scott, 2019). ...
Article
Full-text available
Mealworms ( Tenebrio molitor ) are one of the most common feeder insects fed to exotic animals due to their high acceptance rate, larval longevity, and ease of care. Unfortunately, in their natural commercial state, they are severely deficient in calcium and can predispose exotic animals to hypocalcemia and related metabolic disorders. Gut loading insects with calcium-rich diets is recommended to improve the insects’ nutrient content and to achieve a calcium to phosphorus (Ca:P) ratio of at least 1:1; however, there are few commercial gut loading diets specifically made for mealworms. In this study, mealworms were gut loaded with a newly developed high calcium mealworm diet for 0, 24, or 48 hours. All mealworms were analyzed for dry matter (DM), moisture, calcium, and phosphorus at each time point. Due to the dry nature of the diet, moisture content decreased over time (mean moisture content= 75%, 70%, and 66% at time 0, 24, and 48 hrs, respectively). Calcium content was significantly increased by 24 hrs (p=0.011) and remained elevated at 48 hrs for both the as fed and DM measurements (median calcium DM: 0.07%, 3.5%, and 3.7% at 0, 24, and 48 hrs, respectively). Ca:P ratios were also significantly increased for both the 24 hr (p=0.028) and 48 hr (p= 0.028) periods (median Ca:P DM:1:20, 3.2:1, and 3.6:1 at 0, 24, and 48 hrs, respectively). This data supports the diet’s claim to provide a positive Ca:P ratio in mealworms fed the diet for 48 hours.
... Nutritional deficiency in invertebrates may be improved in two main ways; nutritionally enriched diet fed to the invertebrates (Finke, 2003), and application of supplementary powders immediately prior to feeding to salamanders (Michaels et al., 2014). Live feeder insects kept in captivity for any length of time must be maintained properly in order to maximise nutritional content. ...
... The maintenance of other potential feeder insects is beyond the scope of these guidelines. As invertebrates will defecate and void nutritious gut contents, they must be eaten within hours of being added to salamander enclosures to retain good nutritional content (Finke, 2003). ...
Article
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EAZA Best Practice Guidelines (Striped) fire salamander, Salamandra salamandra (terrestris) is the first version of the EAZA Best Practice Guidelines for this species. This guideline has evolved out of the growing concern for extinction of local fire salamander populations due to the introduction of the invasive chytrid fungus Batrachochytrium salamandrivorans (Bsal) into Europe. Multiple populations of Salamandra salamandra terrestris have collapsed in north-western Europe. Upon the discovery of Bsal, and associated mass mortalities, a captive assurance colony was established in the Netherlands at GAIA Zoo and later also in Rotterdam Zoo. A studbook is managed in ZIMS by GAIA Zoo. In the face of continuous spreading of Bsal into new areas within Belgium and Germany, both countries aim to develop similar ex-situ programs. To ensure collaboration, shared goals and to effectively share knowledge and resources, the multidisciplinary ’Ex-situ Salamandra Group’ (ESG) was initiated by scientists, NGOs and zoos from the three bordering Bsal affected countries. Close collaboration and mutual commitment between all partners involved is the strength of this group. For this ex-situ program, it is necessary to collect available scientific knowledge on genetics, ecology and behaviour, and translate them into practical ways to keep and possibly in a later stage also breed the species. The development of a scientifically based and EAZA (European Association of Zoos and Aquaria) approved husbandry protocol for S. s. terrestris, as lies in front of you, is a first product. The complete literature list can be found at the end of this document. This document consists of two sections: • Section 1. Biology and field data: this part reflects the taxonomic information and information about the subspecies Salamandra salamandra terrestris as this subspecies has been the best studied of all subspecies and it is the focus subspecies for the ESG. It includes data on natural habitat, ecology, behaviour, diet and reproduction; • Section 2. Zoo management: this part includes suggestions about the enclosures, feeding, social structure, breeding, handling, transportation, veterinary problems of the fire salamander and recommended research to extent and improve this guideline. These Best Practice Guidelines are for current keepers who wish to expand their knowledge about this species to take care of the animals in the best possible way, but also for future keepers need for basic information. It is recommended to consult the guidelines and to contact the TAG-members for any questions or problems.
... Insect nutrient composition is affected by various factors, such as life stage and environmental conditions (e.g., temperature and relative humidity); however, diet seems to play a major role 42,43 . Therefore, many researchers have proposed that diet can be used as a tool for the manipulation, to a certain extent, of the body composition of insects and therefore their nutritional value to meet different nutritional demands for various uses 35,37,[43][44][45][46] . This scenario can be achieved either by gut loading, i.e., by providing a diet with increased concentration of a specific nutrient for a short period of time before insect harvesting and consequently increasing the concentration of this nutrient in the insect digestive tract [43][44][45][46] , or by alterations to the body composition of the insect per se after providing a specific diet over the long term 35,37 . ...
... Therefore, many researchers have proposed that diet can be used as a tool for the manipulation, to a certain extent, of the body composition of insects and therefore their nutritional value to meet different nutritional demands for various uses 35,37,[43][44][45][46] . This scenario can be achieved either by gut loading, i.e., by providing a diet with increased concentration of a specific nutrient for a short period of time before insect harvesting and consequently increasing the concentration of this nutrient in the insect digestive tract [43][44][45][46] , or by alterations to the body composition of the insect per se after providing a specific diet over the long term 35,37 . For instance, the chemical composition of penultimate instars and adults of the migratory locust, Locusta migratoria L. (Orthoptera: Acrididae), that were fed throughout their lives (hatchlings to penultimate instars and adults) three different diets varied considerably, enabling its manipulation through the diet 47 . ...
Article
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We evaluated the suitability of forty-four commodities (i.e., cereal flours and meals, non-flour, cereal commodities, legumes and various commodities of vegetative and animal origin) as oviposition and feeding substrates for the yellow mealworm, Tenebrio molitor. Τen T. molitor adults were introduced in plastic vials containing 30 g of each commodity. At the end of the 1 week period, all adults were removed, and mortality was determined; then the vials were further incubated for additional 9 weeks. After this time, the vials were opened, and the larvae of each vial were separated from the feeding substrate, counted and weighed as a group. The efficiency of ingested food conversion was calculated for each substrate. Finally, proximate composition was calculated to determine the nutrient components of the feeding substrates tested and the T. molitor larvae that fed on various selected substrates. In general, adult reproduction was clearly favoured by most amylaceous substrates tested, which was in contrast to the tested legumes on which fewer offspring were produced. Similar effects were observed for larval development. Feeding on selected substrates exerted an impact on the nutrient composition of T. molitor larvae, with a high protein content of the substrate usually resulting in a high protein content of the larvae.
... The calcium content of feeder items can be improved by both gut-loading. i.e. feeding with a high calcium diet prior to being offered to insectivores (Allen and Oftedal 1989;Finke, 2003;Michaels et al. 2015), and dusting with calcium-rich powder (e.g. Michaels et al. 2014). ...
... Separation of uneaten food from the substrate was impossible to allow for weighing it in and out of enclosures, and loss and removal of water and earthworms at different times precluded accurate weighing of the entire culture. Furthermore, although the diets offered as fortified with calcium and, in the case of Nutrogrub, specifically aimed to enhance calcium content of feeder invertebrates, the total calcium content of the artificial diets may have been insufficient (Nutrogrub only barely approaches the optimal concentration range) to elevate calcium content of feeders to levels suitable for insectivore nutrition (Finke 2003;Finke et al. 2005). However, this does not explain why no calcium increase was detected in this study. ...
Article
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The diets provided to many captive insectivores are deficient in calcium and high in phosphorus, which can lead to nutritional disease. Husbandry professionals may address this imbalance through supplementation, but the efficacy of different methods varies between invertebrate taxa. Earthworms are frequently used for aquatic and fossorial insectivores and this along with their rapidly shed mucus layer makes dusting with supplements ineffective; gut loading is likely the only available route to improving nutritional quality. Moreover, earthworms are often considered a good source of calcium, though data exist only for some taxa and results are mixed with regards to calcium content. The present study analysed the calcium and phosphorus content of Dendrobaena veneta earthworms, a species commonly commercially reared and sold for insectivore food, gut loaded on three diets (fresh vegetables, fortified instant porridge oats and a commercial gut loading diet) and quantified the zinc, copper and magnesium content of fasted worms. Dendrobaena worms contained sufficient zinc, copper and magnesium to meet the general requirements of domestic birds, mammals and other vertebrates for these metals. However, calcium and calcium:phosphorus ratios of worms were deficient and did not improve after being offered fortified diets. Insufficient calcium in the diets, unpalatability of food and habituation effects also potentially contributed to this result. Unless better means of improving calcium content of Dendrobaena can be developed, husbandry professionals should be circumspect in their use of this species in a diet and ensure that dietary items with sufficient calcium are also provided.
... Comprehensive data on the mineral contents of edible insects are still scarce. It has been suggested that the mineral content of insects is dependent on and controllable via feed composition (37,128). This could explain the vast variations in the literature. ...
... This is not only due to the species, its origin, and its upbringing (reared or collected in the wild) but also due to the vitamin content of the insects' feed. It has been shown that the vitamin A content of A. domesticus and larvae of T. molitor and B. mori could be increased via feed (37). A literature review of nutrient compositions of edible insects revealed that 100 g of insects based on DM is on average rich in riboflavin, pantothenic acid, and biotin (128). ...
Article
Over the last decade, the urgency to find alternative and sustainable protein sources has prompted an exponential increase in the interest in insects as a human food source. Edible insects contribute suitable amounts of energy and protein, fatty acids, and micronutrients to the human diet. Nutritional values of insects can be manipulated to meet specific needs. Edible insects in food-insecure countries can contribute to improving diets and preventing undernutrition. Bioactive compounds in insects may reduce health risks. Food safety risks are low and mainly relate to those of allergenicity. Strategies to overcome barriers to the consumption of insect products include emphasizing their sustainability, increasing their tastiness, and developing the ability to disguise insects in familiar products. A new sector of insects as food and feed is emerging. Major challenges include legislation, lowering prices by automation and cheap substrates, developing insect products that appeal to consumers, and exploring the health benefits. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
... Nutritional analyses have been performed on most of the commonly available insects commercially raised for food. These analyses have shown that, although insects provide an excellent source of most nutrients, they are usually deficient in calcium, fat soluble vitamins (A, D 3 , and E), thiamine, and omega 3-fatty acids (Finke, 2002(Finke, , 2003. These deficiencies often result in the development of nutritional disorders such as nutritional secondary hyperparathyroidism (NSHP) or hypovitaminosis A (Mans and Braun, 2014;Boyer and Scott, 2019). ...
... Dusting insects with calcium and multi-vitamin powders is simple and can be done immediately prior to the insects being offered as food; however, this method has been shown to be unreliable, as over 50% of the dust falls off or is groomed away in under 2.5 min when applied to crickets (Li et al., 2009). Gut loading insects with calcium and vitamin rich diets is preferred (Allen, 1997); however, these diets can provide variable results based on the duration of gut loading, developmental cycle of the insect, nutritional aspects and quality of the gut loading diet, decreased palatability of the diet to the insect, and higher insect mortality due to nutritional toxicosis (Finke, 2003;Livingston et al., 2014). Because of these limitations, finding insect prey that are more nutritionally complete is warranted. ...
... The nutritional analyses used to measure macro-and micronutrients in insects are similar to those used in estimating the nutrients in plants , and estimating the chitinous exoskeleton in insects is typically based on the acid detergent fiber assay, with adjustments for the ash and the nitrogen that is bound to the chitin (Finke, 2007(Finke, , 2013O'Malley and Power, 2012;Isbell et al., 2013). Like plant material Rothman et al., 2012), it should be noted that there is likely to be intraspecific variability in the nutritional composition of insects within a locale, particularly with respect to the micronutrients based on the insect's food source (Finke, 2002(Finke, , 2003Finke and Winn, 2004). ...
... Although feeder insects provide an excellent source of most nutrients, they may provide inadequate calcium, fat-soluble vitamins, thiamine, and omega 3-fatty acids to the shrews. 3,8,[10][11][12][13]22 To correct any nutritional imbalance, feed insects can be dusted or gut loaded. While dusting with calcium and multivitamin powders is simple, it is rather unreliable due to variables such as poor adhesion (e.g., Tenebrio larvae), or the quick removal of the dust by grooming seen in crickets. ...
Article
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The Etruscan shrew (Suncus etruscus) is one of the smallest mammals on earth and is used in many fields of research, including physiology, behavioral science and neuroscience. However, establishing and maintaining a breeding colony of thisspecies in the laboratory can be challenging, as it requires specific husbandry conditions that greatly differ from those ofmore common laboratory species such as mice or rats. Over the past 15 y, we have successfully established a long-term thrivingcolony of 150 to 200 animals originating from 36 founders. The colony shows longer life expectancy and larger litter sizesthan wild conspecifics. Breeding occurs year-round, independent of seasons, and a breeding pair can regularly produce 2 to 6offspring with an average life expectancy of more than 3 y. The shrews are housed in glass or plastic enclosures on a specificsoil-sand-mixture bedding and are provided with hideouts and nesting material consisting of moss, wood, or bark. Due to their high basal metabolic rate, the shrews require food intake greater than their body weight per day, can hunt arthropodsas large as themselves, and cannot survive more than a few hours without food. Live feed such as crickets or mealworms is crucial and must be provided daily or, at the very least, every 2 d. Although our husbandry practices have constantly been adapted and refined, shrew husbandry remains challenging, and great care is necessary to meet the specific needs of this species. Here, we describe the establishment of a long-term stable colony of Etruscan shrews in a research animal facility and the specific husbandry requirements for animal wellbeing.
... In captivity, hypovitaminosis A is most commonly caused by a lack of dietary intake of preformed vitamin A. Insects are poor sources of preformed vitamin A, that is, retinoids, because invertebrates in general do not convert carotenoids to retinol (Moore 1957) and the majority of retinoids are found in the insects' eyes (Finke 2003). Whole vertebrate prey, in general, contain sufficient preformed vitamin A in their livers (Douglas et al. 1994), which may explain why there are less reports of hypovitaminosis A in reptiles consuming such prey (e.g., snakes). ...
Conference Paper
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... Gut loading is suitable for most nutrients as long as the diet is palatable to the insect, the form of the nutrient is easily consumed by the insect and the diet contains sufficient quantities of the desired nutrient(s). Most research on the effects of gut loading has focused on increasing the calcium content of insects although vitamin A and some other nutrients have been studied [Strzelegicz et al., 1985;Allen and Oftedal, 1989;Pennino et al., 1991;Anderson, 2000;Klasing et al., 2000;Finke, 2003;Hunt-Coslik et al., 2009;McComb, 2010;Oonincx and Van der Poel, 2010;Ogilvy et al., 2012a,b;Attard, 2013]. Gut loading has been shown to be effective in a large number of insect species and the calcium from gut loaded yellow mealworms was shown to be readily available to growing chicks [Klasing et al., 2000]. ...
... Although a captive diet is generally considered low in vitamin A, especially by using commercially bred insects as feeders, this may not explain the widespread incidence of disease. 3,5,7,9,10,20,26 Normal concentrations of vitamin A in most amphibian species are not established for serum, liver, or whole body. Although retinol concentrations have been reported in liver in frog species, 11,17 as well as whole-body concentrations, 3 body vitamin A concentrations, paired serum and liver or paired serum and whole body vitamin A concentrations were obtained. ...
Article
Full-text available
Recent issues surrounding captive amphibians are often nutritionally related problems, such as hypovitaminosis A. Although supplementation of frogs with vitamin A is a topic of investigation, the underlying issue is understanding vitamin A metabolism in amphibian species. To develop a range of "normal" vitamin A concentrations for captive amphibians, baseline vitamin A concentrations must be established in wild amphibian species. In this study, two species, Cuban tree frogs (Osteopilus septentrionalis; n = 59) and marine toads (Rhinella marina; n = 20) were collected from the wild as part of an invasive species control program at Zoo Miami, Miami, Florida. Serum, liver, and whole body samples were analyzed for vitamin A content. The Cuban tree frogs showed higher concentrations on average of vitamin A in serum (82.8 ppb), liver (248.3 IU/g), and whole body (5474.7 IU/kg) samples compared with marine toads (60.1 ppb; 105.3 IU/g; 940.7 IU/kg, respectively), but differences were not significant (P = 0.22). What can be considered "normal" values of vitamin A concentrations across different amphibian species requires further investigation. Although all amphibians collected in this study appeared healthy, a larger sample size of animals, with known health histories and diets, may provide stronger evidence of normal expectations.
... The insects in this report were analysed as is (not fasted) so the mineral composition reported here likely reflects both the minerals in the body of the insects as well as the minerals from recently consumed food remaining in the gastrointestinal tract (Finke, 2003;Oonincx and Van der Poel, 2010). Given their feeding habits this may be why grasshoppers contained much more calcium than both beetles and moths. ...
Article
Insects serve as a major source of nutrients for many animal species, but complete nutritional information of wild insects is lacking. Wild pallid-winged grasshoppers, rhinoceros beetles and white-lined sphinx moths were caught in Rio Verde, Arizona, in the summer of 2013 (grasshoppers and beetle) or the spring of 2015 (moths). Pallid-winged grasshoppers, rhinoceros beetles and white-lined sphinx moths were analysed for moisture, crude protein, fat, ash, acid detergent fibre, minerals, amino acids, fatty acids and vitamins and values compared the nutrient requirements for both rats and poultry as reported by the National Research Council (NRC). The acid detergent fibre was also analysed for nitrogen. When compared to the nutrient requirements as established by the NRC for growing rats, grasshoppers were deficient in calcium, vitamin A, vitamin D, thiamine and vitamin B12, beetles were deficient in calcium, vitamin A, vitamin E, thiamine, pyridoxine and linoleic acid and moths were deficient in calcium, so...
... Calcium accumulation (Figure 1, top) in our crickets was similar to that found in other studies using quasi-equal dietary calcium content, with a Ca:P ratio increasing from 0.17 at 0 h to a peak of c. 0.4 after 24-48 h [11][12][13][14]. This corresponded to a mean (SD) peak calcium content of 2.801(1.018) ...
Article
Full-text available
Calcium metabolism in insectivores may be perturbed by insufficient calcium or vitamin D3. Insects may be gut loaded to increase calcium content, and recent research shows that exposure to UVB radiation can increase the vitamin D3 content of some invertebrates. Typical gut loading protocols result in peak calcium content after 24–48 h, while existing evidence with UVB irradiation involves exposure periods of tens of days. We UVB-irradiated fasted black field crickets (Gryllus bimaculatus) while feeding them on high calcium diets for 48 h, then fasted them for a further 24 h, and measured the vitamin D3, calcium, and phosphorus content compared with non-irradiated controls. UVB irradiation had no effect on vitamin D3 (crickets had no detectable levels of vitamin D3 at any point), or on calcium accumulation rates, which approximated existing research. Crickets significantly increased their calcium:phosphorus ratio from 0.17 to approximately 0.4 over 24 h and this did not increase over a further 24 h of feeding. Removal of the food source resulted in loss of all accumulated calcium within 24 h. Our results have implications for managing food sources for captive insectivores and highlight the importance of good feeder preparation and rapid consumption to ensure optimal calcium delivery to predators.
... Knowing the weight of the insects and the amount of food in its gastrointestinal tract might allow zoo nutritionists and veterinarians to use insects to deliver a wide range of other compounds, such as carotenoids and pharmaceuticals (e.g. anthelmintics) to captive insectivores (Finke, 2003). Insect protein is readily available with protein quality values similar to, or slightly higher than fish meat or soybean meal. ...
Article
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Possibilities of edible insect use in Western countries is now increasingly debated issue. Insects in Asian, African, American and South Central American cultures are mainly nutritional components. In Europe and other developed countries, however, insect is used in different ways, and this issue is viewed from a different angle. Insects are mainly used as feed for animals, in the organic waste recycling systems, in human and veterinary medicine, material production (such as silk) etc. This review summarizes up-to-date knowledge about using edible insects in human, veterinary medicine and agriculture, especially from the viewpoint of the biological and chemical content of active substances and the possibilities of further use in these areas. ©2014 University of Zagreb - Faculty of Agriculture.All rights reserved.
... enriching diet fed to the invertebrates cultured (Finke, 2003), (ii) use of supplementary powders just before feed is given to the salamanders (Michaels et al., 2014). Invertebrates have tissues which are higher in nutritional quality (Ferrie et al., 2014). ...
Book
The book on ex-situ management of amphibians in Indian zoos is a step to support the Indian zoo community in their efforts to house amphibians and streamline their husbandry protocols based on their local conditions.
... Insects are commonly fasted prior to freezing or may be fed a nutrient-rich diet prior to freezing, referred to as gut loading. Fasting assists in mitigating the risks posed by allergens, otherwise the content of the insect's gastrointestinal tract could expose consumers to allergens from the feed [195,196]. For example, crickets raised on insect farms are often fed with high-quality feed such as chicken feed or pet food [194,197]. ...
Article
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Technological advancement and globalization have led to the spread of foods to countries where the food does not yet have a documented history of consumption, in other words, novel foods. Novel foods also encompass truly novel foods, foods that have been processed in a novel manner, and novel means of exposure. With novel foods comes the potential of food allergens that pose an uncharacterized risk to those with food allergies. Food allergies are an increasingly important facet of public health. Therefore, a deeper understanding of novel foods as well as methods to evaluate consumers’ potential risk is necessary. Literature reviews and experimental evaluations leveraging liquid chromatography-electrospray ionization-mass spectrometry were used to explore the risks posed by novel sources of food allergens. Subject sources of allergens included Acheta domesticus, the house cricket, Tenebrio molitor, the yellow mealworm; extensively thermally processed walnut hulls and peanuts, as well as smoke from the wood of tree nut trees, and vapor from E-cigarette liquids. Novel methodologies to interpret complex mass spectrometry data were developed, allowing resultant information to be used in the assessment of allergenic risk. The methodologies developed in this research expand upon the utility of mass spectrometry to evaluate potentially allergenic proteins from poorly characterized sources. Broader characterization of the hazards and risks posed by food allergens permits stakeholders to be more adequately informed regarding the risks they wish to undertake. Advisor: Philip E. Johnson
... Therefore, supplementation of additional Ca and vitamin A and D3 is required. Feeding insects a vitamin-and-mineral-rich diet shortly before feeding them to turtles, which is also known as "gut-loading," will improve their nutritional content (Finke, 2003). Earthworms and night crawlers are also suitable turtle feed; they have high mineral contents because of the high volume of soil in their guts (Bernard et al., 1997). ...
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Freshwater turtles are commonly kept in captivity as pets, bred in zoos for conservation programs, and commercially farmed for pet markets and human consumption, but their nutrition can be challenging. However, based on practical experience, two main strategies may be identified: the use of non-calculated raw diets and the use of balanced commercial feeds. Raw diets are based on fresh, frozen and dried components including invertebrates, fish, rodents and plant matter; they imitate the variety of foods that are accessible to turtles in the wild and are considered most useful when turtles are bred for reintroduction into their natural habitat as part of conservation programs. Granulated, pelleted or extruded commercial diets are frequently used for farmed and pet turtles; they contain animal- and plant-based materials supplemented with vitamin and mineral premixes and calculated to reach the nutrient levels assumed to be optimal for most species. Until more species-specific information on the nutritional requirements of freshwater turtles is available, the Chinese softshell turtle (Pelodiscus sinensis), a commonly commercially farmed species for human consumption, may be used as a reference for other species in terms of suggested nutrients levels. Based on experimental data, the most important nutrients and their levels that should be included in turtle diets are crude protein (39.0 - 46.5%), crude fat (8.8%), Ca (5.7%), P (3.0%), methionine (1.03%), and cysteine (0.25%). The diet composition for freshwater turtles should be based on scientific knowledge and practical experience, so this paper aimed to present and discuss the available data on the nutrient requirements of turtles and the characteristics of the feed materials used in their nutrition.
... Calcium content of prey items may be increased through dusting or gut loading (Finke 2003). However, provision of calcium alone is often insufficient for maintaining normal calcium levels. ...
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Our understanding of captive husbandry for amphibians is rapidly improving as empirical knowledge in this area grows. Early evidence indicates that UVB radiation is an important aspect of captive husbandry for at least some species, and may be critical in combatting nutritional metabolic bone disease and other environmentally linked diseases. However, the limited evidence in this field is restricted to post-metamorphic anurans, and impacts of UVB provision on larvae are even less well known. We measured the effects of ecologically appropriate levels of UVB exposure on growth rates, pigmentation acquisition, serum vitamin levels in the blood plasma, and whole-body mineral content in the Mallorcan midwife toad (Alytes muletensis). There were no significant effects of UVB exposure on any parameters measured. We were therefore unable to provide clear evidence that UVB irradiation can be used to synthesise vitamin D3 in the skin. Our data suggest that when A. muletensis larvae have access to a diet containing vitamin D3 and under husbandry conditions currently recognised as best practice, UVB irradiation is not required to maintain this species successfully. These results do not indicate that UVB provision is unimportant for amphibian larvae in general, however. Further research is needed to elucidate how tadpoles interact with UVB radiation in nature and to examine how UVB radiation is provided in captivity, and to test for effects using a wider variety of species from a range of different habitats.
... This gutload thus affects analyzed nutrient profiles. Finke (2003) reports a gutload content of approximately 5% of the total dry matter for adult house crickets and yellow mealworms. At the 4% inclusion level in the current study, this would result in an overestimation of approximately 1% of TFA. ...
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Edible insects are advocated as sustainable and healthy food and feed. However, commercially produced insects are often low in n‐3 fatty acids and have suboptimal n‐6/n‐3 ratios. A certain amount and proportion of these FAs is required to optimize human health. Flaxseed oil consists primarily (57%) out of alpha‐linolenic acid. An experiment was conducted to quantify the effect of flaxseed oil provision on fatty acid composition and to determine the quantity needed to attain a beneficial n‐6/n‐3 ratio. Three species were used in the experiment: house crickets (Acheta domesticus [L.]), lesser mealworms (Alphitobius diaperinus [Pfanzer]) and black soldier flies (Hermetia illucens [L.]). These were provided with either a control diet or a diet enriched with 1%, 2% or 4% flaxseed oil during their larval / nymphal stage. Fatty acid profiles of diets and insects were determined via GC‐MS. The three species had distinct fatty acid profiles on all four diets, but responded similarly to flaxseed oil addition. For each percent added to the diet, the alpha‐linolenic acid content of the insects increased by 2.3%‐2.7%. Four percent addition increased the n‐3 fatty acid content 10–20 fold in the three species and thereby strongly decreased n‐6/n‐3 ratios from 18–36 to 0.8‐2.4. A ratio below 5 is considered optimal for human health and was achieved by 2% flaxseed oil inclusion for house crickets and lesser mealworms, and at 1% inclusion for black soldier flies. Adding a source of n‐3 fatty acids to insect diets can thus improve the nutritional quality of insects. This article is protected by copyright. All rights reserved
... The horizontal line at the bottom of each boxplot is the minimum value for each group; the lower limit of each box is the lower quartile; the heavy line inside each box is the sample median; the upper limit of each box is the upper quartile; the horizontal line at the top of each plot is the maximum value. Hepatic vitamin A concentrations are significantly different between groups (p = 0.03) 2003, 2013Livingston, Lavin, Sullivan, Attard, & Valdes, 2014). ...
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Although leopard geckos (Eublepharis macularius) are commonly kept under human care, their vitamin requirements are largely unknown. Many invertebrate preys display a low vitamin A concentration; thus, gut‐loading insects with vitamin A or carotenoids is a common practice. The objective of this prospective experimental study was to investigate whether dietary supplementation with β‐carotene, including prey gut‐loading, leads to sufficient vitamin A hepatic storage and prevents epithelial squamous metaplasia development in leopard geckos. Ten clinically healthy female leopard geckos were randomly divided in two groups with various supplementations: a group receiving vitamin A supplementation and a group receiving β‐carotene. Insects were gut‐loaded continuously with a supplement containing vitamin A or β‐carotene, depending on the group. Oral supplementation with cod liver oil or carrot juice was administered weekly to each lizard from “vitamin A group” and “carotenoid group” respectively. After 10 weeks of supplementation, surgical hepatic biopsies were obtained in three geckos of each group while the two remaining geckos were euthanized to undergo complete necropsy. Hepatic vitamin A concentration was determined for each lizard (n = 10) by ultra‐performance liquid chromatography. Histopathology revealed hepatocellular vacuolization and vitellogenic follicles in five females. Epithelial squamous metaplasia was not observed in any of the geckos. Hepatic vitamin A concentration was significantly higher in the carotenoid‐supplemented group than in the vitamin A‐supplemented group (p = 0.03). Our results suggest that in leopard geckos, dietary supplementation with β‐carotene allows sufficient vitamin A hepatic storage.
... It could be easily discerned from these values that the benefits of each edible insect species can vary significantly. In addition, analogous to shellfish or prawns, the type of habitat and diet of these insects can also change their flavour and even their nutritive values (Ramos-Elorduy et al., 1997;Klasing et al., 2000;Finke, 2003;Raksakantong et al., 2010;Oonincx and van der Poel, 2011;Nowak et al., 2016). As grasshoppers (Zonocerus variegatus) in Nigeria were fed with bran, which contains more fatty acids than that of corn, these insects demonstrated almost doubled protein levels (Ademolu et al., 2010). ...
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Although unconventional in the USA, entomophagy, or the practice of consuming insects, can provide a nutritious relief to many malnourished people in developing countries. Edible insects are part of numerous traditional diets found in over 113 countries, including those in Asia, Africa, and South America. Currently, there are 2 billion people consuming over 2000 recorded edible insects. Many of these worldwide insects contain amounts of protein, fat, vitamins, and minerals comparable to commonly eaten livestock. With the popularity of crickets in both developing and developed countries and the nutrient density of locusts, these insects were of particular interest. Rice flour, made from a major food crop around the world, was used as an effective vehicle to deliver these insect ingredients. The use of inexpensive single-screw cold-forming extrusion technology, due to its capability of high production rate yet low capital and operating costs, was employed in making insect-fortified products. The feasibility of incorporating edible insect flours from cricket and locust in an extruded rice product has been demonstrated to be successful with acceptable shelf stability and sensory characteristics. Nutritionally, the insect rice products developed were energy dense (high fat content) and as an excellent source of protein. They also contained considerable amounts of dietary fibre and iron. Sensory evaluations involving 120 untrained panelists–suggested cricket formulations were well accepted compared with locust formulations. There is a positive outlook on the overall acceptance of entomphagy even in developed countries. As a staple food providing 20% of the world’s dietary energy and consumed by over 1 billion people, rice is an ideal vehicle to deliver nutrients carried by edible insects. The incorporation of insect flours in processed foods such as extruded rice products can greatly promote the consumer acceptance by disguising the ‘yuck’ factor associated with intact insects.
... 1,29,30 Gut loading feeder insects before feeding them to insectivores can also improve their nutritional quality and correct Ca : P ratios. 15,17 However, excessive supplementation may also result in health problems. 14, 15 We did not find any symptoms of excessive dietary intake, such as mineralization of soft tissues 14 in any CT image of the study animals. ...
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Captive rearing programs have been initiated to save the European common spadefoot (Pelobates fuscus), a toad species in the family of Pelobatidae, from extinction in The Netherlands. Evaluating whether this species needs ultraviolet B (UVB) radiation and/or dietary supplementation for healthy bone development is crucial for its captive management and related conservation efforts. The bone mineralization in the femurs and the thickest part of the parietal bone of the skulls of European common spadefoots (n = 51) was measured in Hounsfield units (HUs) by computed tomography. One group, containing adults (n = 8) and juveniles (n = 13), was reared at ARTIS Amsterdam Royal Zoo without UVB exposure. During their terrestrial lifetime, these specimens received a vitamin-mineral supplement. Another group, containing adults (n = 8) and juveniles (n = 10), was reared and kept in an outdoor breeding facility in Münster, Germany, with permanent access to natural UVB light, without vitamin-mineral supplementation. The HUs in the ARTIS and Münster specimens were compared with those in wild specimens (n = 12). No significant difference was found between the HUs in the femurs of both ARTIS and Münster adults and wild adults (P = 0.537; P = 0.181). The HUs in the skulls of both captive-adult groups were significantly higher than in the skulls of wild specimens (P = 0.020; P = 0.005). The HUs in the femurs of the adult ARTIS animals were significantly higher than the HUs in the femurs of the adult Münster animals (P = 0.007). The absence of UVB radiation did not seem to have a negative effect on the bone development in the terrestrial stage. This suggests that this nocturnal, subterrestrial amphibian was able to extract sufficient vitamin D3 from its diet and did not rely heavily on photobiosynthesis through UVB exposure.
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Proper care and husbandry are the most important factors in keeping captive reptiles healthy. Improper nutrition, supplementation, caging, lighting, substrate, temperature, and humidity can all lead to stress and development of disease. Presented here are current recommendations for keeping captive reptiles. Care has moved away from sterile, spartan enclosures to larger, more naturalistic habitats. These habitats provide more space and choices for the reptile, leading to higher activity levels, reduced stress, and more opportunities to exhibit natural behaviors. Reptiles benefit from enrichment and are amenable to training in order to reduce stress and allow easier handling and veterinary care. Copyright © 2015 Elsevier Inc. All rights reserved.
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Edible insects are considered rich in protein and a variety of micronutrients, and are therefore seen as potential contributors to food security. However, the estimation of the insects’ contribution to the nutrient intake is limited since data are absent in food composition tables and databases. Therefore, FAO/INFOODS collected and published analytical data from primary sources with sufficient quality in the Food Composition Database for Biodiversity (BioFoodComp). Data were compiled for 456 food entries on insects in different developmental stages. A total of 5734 data points were entered, most on minerals and trace elements (34.8%), proximates (24.5%), amino acids (15.3%) and (pro)vitamins (9.1%). Data analysis of Tenebrio molitor confirms its nutritive quality that can help to combat malnutrition. The collection of data will assist compilers to incorporate more insects into tables and databases, and to further improve nutrient intake estimations.
Chapter
This chapter focuses primarily on theraphosids, since these are the most common species under human care. Some of the most commonly kept Theraphosidae species include the Mexican redknee tarantula ( B. hamorii ); Chilean rose tarantula ( Grammostola rosea ); goliath bird eater ( Theraphosa blondi ), curlyhair tarantula ( Brachypelma albopilosum ), and pinktoe tarantula ( Avicularia avicularia ) from the Americas; and the Asian ornamental tarantulas ( Poecilotheria spp. ). In North America, Aphonopelma species such as the Texas brown tarantula ( Aphonopelma hentzi ) and desert blonde tarantula ( Aphonopelma chalcodes ) are commonly kept because of their natural occurrence in southern areas of the United States. Spider neurobiology has been better researched than many other aspects of arachnid anatomy and physiology. Postmortem examination of spiders from a collection may be more rewarding than clinical examination of a live, debilitated spider. Administration of medication in spiders can be challenging due to their small size, the presence of an exoskeleton, and relative lack of published drug dosages.
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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.
Chapter
Reptiles (lizards, snakes, turtles, and crocodilians) are becoming increasingly popular as models for developmental investigations. In this review the leopard gecko, Eublepharis macularius, is presented as a reptilian model for embryonic and tissue regeneration studies. We provide details of husbandry and breeding and discuss aspects of embryonic nutrition, egg anatomy, and sex determination. We provide comprehensive protocols for transcardial perfusion, short-term anesthesia using the injectable anesthetic Alfaxan, and full-thickness cutaneous biopsy punches, used in geckos for the study of scar-free wound healing. We also provide modifications to three popular histological techniques (whole-mount histochemistry, immunohistochemistry, and double-label immunofluorescence) and provide details on bromodeoxyuridine (BrdU) labeling and immuno-detection.
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The interest in eating insects has grown in Western countries. Insects are on the market in some European countries due to the reinterpretation of EU legislation. In this study, house crickets (Acheta domesticus) were reared with two homemade and one commercial feed with different chemical compositions. Commercial chicken feed, which contained the highest levels of protein and minerals, produced the biggest and the most protein- and mineral-containing crickets. The protein content varied between 50.2 and 64.2 g/100 g (dry weight, DW). The examination of the amino acid profiles showed that the feed had a smaller effect on them than the amount of protein. Crickets, which received the most carbohydrate-rich feed, were highest in fat and lowest in protein. The fat content of all crickets was high (25.0–33.7 g/100 g, DW), and an average fatty acid profile was 40% saturated fatty acids (SFAs), 31% monounsaturated fatty acids (MUFAs), and 27% polyunsaturated fatty acids (PUFAs). A cricket’s diet has a significant effect on its composition.
Chapter
This chapter provides a nutritional primer for wildlife professionals raising nestlings of species that, in the wild, would be fed predominantly insects or other arthropods. The insect species most commonly cultured for food include house crickets, waxworms, mealworms and superworms, soldier flies, fruit flies and several species of roaches. As the primary food for many wild nestlings, insects in general should supply adequate levels of protein, amino acids, fatty acids, plus most minerals and vitamins. Assuming an adequate supply of foodstuffs, wild birds are presumably able to select a variety of arthropods that, in the proper proportions, provides nestlings a diet that is sufficient for growth. Cultured insects presumably offer a close approximation to the natural diet of insectivorous nestlings; however, they are expensive, and supplementing them with appropriate amounts of selected nutrients can be challenging.
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Information on the nutritional values of reptile feeds is limited. In this study alternative invertebrate preys (Madagascar hissing cockroach, rusty red cockroach, dubia cockroach, black and banana cricket) and turtle feed (dried crabs, dried and frozen whole fish, pellet, lyophilized beef hearth) were analysed. Dried crabs had much higher calcium content (39.1-59.8 g/kg) than cricket and cockroach species (0.7- 2.5 g/kg DM). The crude fat content of the crabs is lower (2.3-5.2% DM) than that of the cricket and cockroach species (11.5-30.5% DM). Relevant differences were not found between cockroaches and crickets. Commercial pellet had very low calcium and crude protein content (2.71 g/kg and 27.3% DM) related to the other feeds. All of the examined invertebrates are adequate for reptiles. For carnivore turtles, whole frozen fish is a good choice, which is an adequate source of calcium and vitamins.
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It is well known that secondary chemicals produced at one trophic level may affect organisms at subsequent levels of the food chain. Effects of nutrient supplements may also propagate through trophic levels, but the mechanisms here are less clear. We tested the hypothesis that predators can be affected by the nutrient composition of the prey's food. Wolf spider (Pardosa amentata) hatchlings were raised ad libitum on fruit flies (Drosophila melanogaster) that were cultured in poor basic medium with additions of different nutrients. These additions strongly affected the performance of the spiders. Growth rates increased when additions consisted of 19 different amino acids or fatty acids+cholesterol or commercial dogfood. Survival increased in spiders reared on fruit flies from cultures containing 19 amino acids or methionine or dogfood. The addition of dogfood increased spider growth and survival more significantly than the addition of any single nutrient group alone. Adult female flies from the dogfood culture were significantly heavier than females from the basic culture. The nutrients added to the fruit fly media were thus able to create biological effects at both the second and the third trophic levels. To test whether nutrients passed to the predators through the gut content of the prey, we included a treatment where the spiders were fed flies that had been starved for 48 h in order to empty their guts. Gut emptying of the flies did not reduce the positive effects of the enriched fruit fly media, i.e. the nutritional benefits were not due to nutrients that passed directly through the guts of the flies. Since the nutrients added to the fruit fly media were separated from the spiders that benefited from them by two trophic transformations, this phenomenon was a true tritrophic interaction.
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We describe the use of alerito, the larva of the Rhynchophorus palmarum (Coleoptera: Curculionidae), by the Jivi (Guajibo) community of Alcabala de Guajibo, Amazonas, Venezuela. The Indians gather the palm worms from damaged or fallen palm stems and eat them raw or roasted. We analysed the nutrient composition of the palm worm and found that it is an excellent source of protein, vitamins A and E, and minerals. We further describe the development of a local, controlled small‐scale palm worm production system for use by the Indians in the Amazon. Larvae are bred using wild palm materials and traditional Indian plants. The larval survival and density in each palm substrate is analysed together with the larvae's nutritional composition, and comparison with the mother palms cucurito (Maximiliana maripa), seje (Jessenia bataua) and moriche (Mauritia flexuosa) is made. Finally, the palatability of the palm worm to non‐Amerindian tourists is assessed. The nutrient composition of the palm worm, the simplicity of a more controlled local production system and the acceptability of the palm worm to tourists make this non‐conventional resource promising both as a nutritional food and as a source of cash income for the Indians.
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It is often assumed that prey species consumed by generalist predators are largely, though not entirely, equivalent in terms of their value to the predators. In contrast to this expectation, laboratory feeding experiments uncovered distinctly varied developmental responses of a generalist predator, the wolf spider Schizocosa, to different experimental diets. Naive Schizocosa attacked and fed upon all the prey species offered; however, highly divergent patterns of survival, development, and growth of Schizocosa spiderlings reared on different single-prey diets revealed a wide spectrum of prey qualities. Spiderlings fed the collembolan Tomocerus bidentatus sustained the highest overall rates of survival, growth, and development. Fruit flies (Drosophila melanogaster) were intermediate-quality prey: spiders fed Drosophila initially exhibited rates of survival, growth, and development equal to those of spiders on a diet of T. bidentatus, but after about 3 months, rates declined markedly. Fungus gnats (Sciaridae; Bradysia sp.) and conspecfic spiderlings are low-quality prey for Schizocosa: a sole diet of either of these prey types resulted in positive but markedly submaximal rates of growth, retarded rates of development, and survival rates much lower than that supported by a diet of Drosophila. Worst were the collembolans Folsomia candida and Isotoma trispinata, and the aphid Aphis nerii: spiderlings fed solely one of these species did not grow and died without molting. A. nerii is classified as poor quality because survival was no better than that of starved controls. F. candida and I. trispinata were toxic: survival of Schizocosa hatchlings fed these collembolans was lower than that of starved controls. A mixed diet of T. bidentatus and fruit flies yielded positive synergistic effects with respect to growth, but development and rate of survival were similar to those of spiders on a sole diet of T. bidentatus. Including toxic prey did not produce a better diet, while inclusion of toxic prey with prey of higher quality created diets that were no better than the toxic prey alone. The results of these experiments suggest that prey species that are similar in morphology and behavior, and that are initially killed and consumed, may differ dramatically in their suitability as food for generalist arthropod predators.
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Insects used in zoo feeding programs are poor sources of calcium (Ca) and have inverse calcium : phosphorus (Ca:P) ratios. An experiment was conducted to determine if feeding diets high in dietary Ca to adult crickets would cause an increase in whole-body Ca content. Experimental diets were formulated to contain 2, 4, 6, 8, 10, and 12% Ca and were provided to the crickets for 12, 24, 48, 72, 96, and 120 hr. Crickets were analyzed for dry matter, Ca, and phosphorus. Dietary treatment and duration of treatment were found to have significant effects on Ca content and Ca:P ratio of crickets, but not on P content. The Ca content and Ca:P ratio of crickets increased during the initial period of feeding, but after 48 hr these mineral levels remained stable. Calcium content and Ca:P ratio of crickets were a function of dietary Ca, reaching maximal values of 1.4% and 1.7:1, respectively, when diets containing 12% Ca were fed. Radiographs revealed radiopaque material in the gastrointestinal tracts (GIT) of most crickets fed diets high in calcium (8, 10, or 12% Ca) but not in the GIT of crickets fed diets low in calcium. It is concluded that in order to obtain crickets with a Ca:P ratio of 1:1 or higher it is necessary to feed diets containing at least 8% Ca. Other factors which might influence the calcium content of crickets are discussed.
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Weanling Sprague-Dawley rats were fed diets containing corn gluten meal (CGM), Mormon cricket meal (MCM), MCM supplemented with methionine (MCM + Met) or CGM-MCM mixtures as the sole source of dietary protein in purified diets. Animal response (weight or nitrogen gain) was analyzed as a function of nitrogen intake and described by a series of curves using a four-parameter logistic model. Parameter sharing was used to differentiate statistically between the response curves. When used for maximum nitrogen retention the quality of the protein sources could be ranked as follows: MCM + Met greater than 40 CGM-60 MCM greater than 50 CGM-50 MCM greater than 60 CGM-40 MCM greater than MCM greater than CGM. When used for maximum weight gain the ranking was as follows: MCM + Met greater than 40 CGM-60 MCM greater than 50 CGM-50 MCM greater than 60 CGM-40 MCM greater than MCM greater than CGM. The rankings of the protein sources when used for weight maintenance or nitrogen equilibrium were similar to those seen for maximum weight or nitrogen gain except for the ranking of MCM, which changed from fifth to first. These results show MCM to be a good quality protein source and that methionine is the first limiting amino acid when used for growth but not for maintenance. The shape of the response curves was dependent upon the response criteria as well as the source of dietary protein. The factors that may affect the shape of the dose-response curves and the application of nonlinear models toward animal feeding programs are discussed.
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Eight nonreproductive female Drakensberg crag lizards (Pseudocordylus melanotus melanotus) were each fed diets of mealworms and calcium capsules with various calcium levels. Excreta were collected and analyzed for calcium and uric acid content. The amount of calcium in the feces was calculated. The lizards appeared to be able to maintain calcium balance at calcium intakes equivalent to 1.4-5.6% calcium in the dry matter of feed. Calcium balance was maintained by adapting intestinal calcium absorption.
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Vitamin A and its derivatives (retinoids) are essential components in vision; they contribute to pattern formation during development and exert multiple effects on cell differentiation with important clinical implications. It has been known for 50 years that the key step in the formation of vitamin A is the oxidative cleavage of β-carotene; however, this enzymatic step has resisted molecular analysis. A novel approach enabled us to clone and identify a β-carotene dioxygenase from Drosophila melanogaster,expressing it into the background of a β-carotene (provitamin A)-synthesizing and -accumulating Escherichia coli strain. The carotene-cleaving enzyme, identified here for the first time on the molecular level, is the basis of the numerous branches of vitamin A action and links plant and animal carotene metabolism.
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The purpose of these studies was to determine the husbandry variables that optimize the Ca content of mealworms (Tenebrio molitor) and to determine the bioavailability of this Ca for bone mineralization in chicks that consume the mealworms. To determine the optimal level of Ca in the substrates used in short-term (< 14 days) holding of mealworms and to determine the length of time that mealworms should be exposed to high-Ca substrates, mealworms were placed in either a wheat bran or a chicken starter substrate supplemented with 0, 4, 8, or 12% Ca from CaCO3. The mealworms were harvested after 0.5, 1, 2, 3, 4, 7, or 14 days. The Ca content of the mealworms was greatest with the use of chicken starter and increased linearly with the Ca content of the substrate. In general, the Ca content of the mealworms increased during the first 24 hr and decreased after > or = 1 wk, especially at the higher levels of Ca supplementation. The chicken starter also resulted in higher levels of vitamin D in mealworms. Mealworms held in wheat bran with 8% Ca were fed to growing chicks. Ca bioavailability was calculated from the chicks' bone ash. The Ca in these mealworms was 76% as bioavailable as the Ca in oyster shell.
Chapter
Vertebrates require vitamin D for several bodily processes including the regulation of calcium and phosphorus levels1. Vitamin D is obtained in two ways. First, vitamin D can be obtained from the diet2. Second, vitamin D can be produced in the skin upon exposure to ultraviolet B irradiation (UVB, 280–315nm)2.
Chapter
The panther chameleon is a hardy captive with potential as a model organism for laboratory research and educational exhibition. However, husbandry problems prevent hatching of eggs from captive-raised females. Previously we have shown that ultraviolet B (UVB) irradiation will prevent term-death of embryos [1], presumably by allowing production and proper regulation of vitamin D by the mothers. Panther chameleons perceive UV irradiation and may be able to adjust their exposure to compensate for low dietary intake of vitamin D3 [2]. This research was to define the optimum dose of UVB irradiation for breeding panther chameleons Furcifer pardalis kept on a low dietary level of vitamin D in captivity. We subjected chameleons to specified doses of UVB irradiation within a broad range of exposure possibilities. Results will aid future study of UV photobiology.
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An inductively coupled plasma sustained in flowing argon and a permanently aligned all-glass coaxial pneumatic nebulizer are employed in the atomic emission mode with a direct-reading polychromator for simultaneous multielement determinations. The inductively coupled plasma is shown to be remarkably free from matrix and interelement effects by application for the determination of major (Na, K, P, Ca, and Mg) and trace (Fe, Cu, Zn, Mn, Pb, Cd, Co, Cr, Ni, V, Ti, Al, Sr, and Ba) elements in reference biologic materials and soil extracts. Wet-digestion and several dryashing sample preparation procedures are evaluated. Accuracy, precision, and sensitivity compare favorably with other multielement instrumental techniques (neutron activation analysis) energy dispersive x-ray fluorescence, solution-rotating disk atomic emission spectrometry) and with flame atomic absorption spectrometry. The directness of the method reported here is illustrated by use of one set of system operating conditions with one set of synthetic reference solutions used to establish a single calibration curve for each element.
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Arboreal termites (Nasutitermes spp.) and stomach contents from tamanduas (Tamandua tetradactyla) were collected in central Venezuela during the mid part of the dry season (March) of 1993 and 1994. Nutritional analyses were performed on each caste (workers (n = 3), soldiers (n = 5), and alates (n = 1)), on mixed caste samples (n = 1), and on stomach contents from live (n = 5) and roadkill (n = 5) tamanduas. The chemical analysis, expressed on a dry matter (DM) basis, of termite workers, which constituted the majority of the nest populations, showed the highest crude protein (CP) (67%) and the lowest DM (25%) and fat (2%) values. Ash content varied from a low of 4% in alates to a high of 7% in soldiers. The alates contained substantially higher DM (41%) and fat (40%), which was reflected in a higher caloric value (6.88 kcal/g) (gross energy) (GE)), and relatively less CP (49%). Among the macrominerals, potassium (K) was consistently the highest, with an overall mean value of 0.54%, while the calcium (Ca) and phosphorus (P) levels showed overall means of 0.26% and 0.67%, respectively. Iron (Fe) was the highest among the trace minerals but highly variable (soldiers, 1,000 ppm; alates, 246 ppm; workers, 394 ppm). Differences in the concentrations of vitamin A and E were found among termites castes, with soldiers showing the highest values (20 and 85 µg/g for retinol and a-tocopherol, respectively). Acid detergent fiber (ADF) was lower in the alates (13%) and workers (27%) compared to the soldiers (35%). Alates' fat was more saturated (39%), while soldiers and workers had a much higher polyunsaturated fatty acid (PUFA) concentration. In general, similar nutrient profiles were found between the tamandua stomach contents and the overall mean composition of Nasutitermes spp. However, stomach contents had much higher ADF, ash, and Fe concentrations (3 1%, 14%, and 2,748 ppm) than termites (25%, 5%, and 652 ppm) but lower CP, fat, GE, and Ca values (51%, 11%, 4.58 kcal/g, and 0.11% vs. 58%, 15%, 6.01 kcal/g, and 0.26% in termites). The relatively low concentrations of Ca in both stomach contents and termites may be indicative of a low requirement in Myrmecophaga compared to other mammalian species. Diets consumed by free-ranging
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The parsnip webwormDepressaria pastinacella, acquires a distinct yellow stripe when it consumes the yellow flowers of its principal host plantPastinaca sativa, the wild parsnip. Caterpillars raised on artificial diet lacking host-plant material lack this yellow coloration. By chemical characterization and comparison of caterpillars raised on parsnip flowers and on artificial diet, we were able to determine that lutein, along with smaller amounts of other xanthophylls from the host plant, is selectively sequestered in the fat body. In bioassays designed to measure avoidance of ultraviolet light, caterpillars raised on parsnip flowers or on artificial diet supplemented with lutein were less likely to avoid exposure to ultraviolet light than caterpillars raised on unaugmented artificial diet and thus lacking sequestered carotenoids. The ability to sequester xanthophylls, which are highly effective antioxidants, may confer a selective advantage on these caterpillars, whose apiaceous host plants produce large quantities of furanocoumarins, natural products that are photoactivated by light wavelengths in the ultraviolet region; such sequestered pigments may reduce not only the oxidative stress associated with ultraviolet light and diurnal foraging but also the photooxidative stress associated with ingestion of photoactive furanocoumarins.
Article
Low calcium (Ca) contents and low calcium:phosphorus (Ca:P) ratios of mealworm larvae and house crickets can result in imbalances of Ca and phosphorus (P) in diets of avian species when these insects form more than a minor proportion of the diet. Appropriate dietary Ca and Ca:P levels are particularly important for normal growth and bone development in chicks, especially of long-legged species such as bustards. Two experiments were carried out to evaluate the efficacy of a selection of practicable dietary options for increasing the Ca levels and Ca:P ratios of cultured mealworm larvae and immature house crickets used for feeding bustards. Dietary treatments contained higher levels of Ca than the insects' standard culture diet components but similar P levels. Dietary treatment significantly increased Ca level and Ca:P ratio of both mealworm larvae and immature house crickets but did not affect P content of either species. Acceptable insect Ca and Ca:P levels were achieved by maintaining insects on commercial high-Ca diet products for as little as 24 hours. Other factors that may have influenced the Ca levels of mealworm larvae and house crickets include physical form and overall nutrient composition of their diets. Zoo Biol 19:1–9, 2000. © 2000 Wiley-Liss, Inc.
Article
Carotenoids in 38 species of Lepidoptera have been examined qualitatively and quantitatively. Comparisons are made between cryptic and aposematic species, pupae and adult, dried and fresh material, males and females, and certain polymorphic species. Although some selective storage is demonstrated, Lepidoptera chiefly store the carotenoids present in their food plants unchanged. It was found that the Large White (Pieris brassicae), a toxic species, stored more carotenoids than the less toxic Small White (P. rapae) while ab. coerulea (P. brassicae) contained only 25 % of the carotenoids found in typical specimens.
Article
To assess the importance of diet and light for indoor maintenance, hatchling panther chameleons were reared for 1 year on crickets fed diets that differed in vitamin concentrations and in different light environments. Dietary transfer of vitamins from the cricket diet to the lizards via the crickets was quantified, as was UV irradiance. There was a statistically significant dietary enhancement of growth by both vitamins on males. UV-A irradiation significantly suppressed growth of females. Low vitamin A shortened life span and resulted in a number of gross and histological pathologies. Hepatocellular lipidosis, indicating a possible toxicosis, occurred with all diets and light treatments. Higher vitamin A resulted in mild soft-tissue mineralization, and high vitamin D shortened the life span of females. Low vitamin A drastically reduced reproduction in both sexes. The intermediate levels of dietary vitamins resulted in the best production of viable eggs by females. However, without high UV-B irradiation, all viable eggs died at term and contained different vitamin levels than hatching eggs from wild-caught females. Baseline levels of egg calcium are given for hatching eggs from wild-caught females. Modifications in current husbandry procedures are recommended. © 1996 Wiley-Liss, Inc.
Article
Although nutrient requirements of insectivores have not been specifically determined, detailed chemical analysis of invertebrates used in zoo feeding programs is essential for evaluating nutritional adequacy based on domestic animal models. Additionally, such data can provide valuable suggestions for future research priorities. Proximate composition, fat-soluble vitamins, and minerals in mealworms (Tenebrio molitor and Zophobas morio), crickets (Acheta domesticus), waxworms (Galleria mellonella), fruit flies (Drosophila melanogaster), and earthworms (Lumbricus terrestris) were determined. All species had a water content >50% of their body weights. Larval invertebrates had higher fat content (x >30% dry matter [DM]) than adult species. Total nitrogen (N) ranged from 5.2±1.1% DM (earthworms) to 10.3±0.4% DM (adult crickets), whereas chemically bound N comprised 3–10% of total N in all invertebrates. Neutral detergent fiber, used as a measure of chitin, averaged 15.3±3.6% DM for all species except wild-caught earthworms, which were higher (51% DM). Vitamin E concentrations ranged from 15±3 IU/kg DM (mealworms) to 509±232 IU/kg DM (waxworms). Vitamin A concentrations were undetectable (fruit flies) to low in all samples; none met the recommended dietary vitamin A concentrations established for domestic carnivores. Insects had low calcium concentrations (x = 0.11%) and imbalanced calcium:phosphorus ratios except for pinhead crickets. Insects sampled contained sufficient concentrations of Cu, Fe, Mg, P, and Zn to meet known requirements of domestic birds and mammals, whereas supermealworms and waxworms contained deficient levels of Mn. Earthworms appeared to meet dietary mineral requirements, based on domestic bird and mammal recommendations. Zoo Biol 17:123–134, 1998. © 1998 Wiley-Liss, Inc.
In the class Insecta, three retinal congeners are used as the chromophore of visual pigments: retinal, (3R)-3-hydroxyretinal and (3S)-3-hydroxyretinal. The distribution of retinal and 3-hydroxyretinal superimposed on the phyletic tree of insects indicates that the original chromophore of visual pigments was retinal, and that some insects arose around the end of the Carboniferous period acquired the ability to use 3-hydroxyretinal. Xanthophylls possesing 3-hydroxy-β-ring have been considered to be precursors of 3-hydroxyretinal, and the “oxygen pulse” in the late Palaeozoic era is discussed as a possible contributory factor in obtaining the ability to use 3-hydroxyretinal as the visual pigment chromophore. Xanthophylls possessing 3-hydroxy-β-ring produced by plants and bacteria have only the (3R)-β-ring, so the 3-hydroxyretinal produced directly from such xanthophylls is expected to be (3R)-3-hydroxyretinal. On investigating the absolute structure of 3-hydroxyretinal in insect compound eyes, using a chiral column, the orders Odonata, Hemiptera, Neuroptera, Coleoptera, and Lepidoptera, and suborders Nematocera and Brachycera of the Diptera were found to have only (3R)-3-hydroxyretinal. The members of the dipteran suborder Cyclorrhapha, however, were found to contain a mixture of both the (3R)- and (3S)-enantiomers of all-trans 3-hydroxyretinal and (3S)-11-cis 3-hydroxyretinal. The Cyclorrhapha, which arose in the Jurassic period, have obtained the ability to produce (3S)-3-hydroxyretinal, but the metabolic pathway by which these “higher flies” form (3S)-3-hydroxyretinal has yet to be clarified.
Article
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 D3. 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 D3 (100%), vitamin A (89%), vitamin B12 (75%), thiamin (63%), vitamin E (50%), iodine (44%), manganese (22%), methionine-cystine (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.
Article
Copyright: 1982 Academy of Science of South Africa The use of the caterpillar of the Mopanie moth (Conimbrasia belina) as a food by the Pedi nation has been described in detail by Quin, who also recorded data on the average weight and moisture, protein and fat contents of the fresh caterpillars. However, with the exception of the recordings in 1968 pf a figure for the digestibility of the protein component of one sample of traditionally prepared, dried Mopanie caterpillars by Dreyer, no further work has been done to assess the nutritive value of this indigenous foodstuff. The Mopanie ‘worm’ has, nevertheless, made impressive gains in importance as a product for sale in recent years. According to an estimate by the SA Bureau of Standards, annual sales through agricultural cooperative markets now amount to about 40 000 bags, each bag containing 40 Kg of traditionally prepared, dried caterpillars. Furthermore, a considerable degree of sophistication has been introduced into the market by the recent establishment of Mopanie worm cannery at Peitersburg, Northern Transvaal.
Article
The distribution of 3-hydroxyretinal (R3), a recently discovered retinoid used as the visual pigment chromophore in some insects, was investigated in the class Insecta using HPLC technology. We studied 138 species in 24 orders, sampling from a wide range of taxonomic groups as well as varied habitats. In addition to groups already known to have R3, we find this retinoid in Hemiptera (suborder Heteroptera), Plecoptera, Megaloptera, and Hymenoptera. We also find retinal (R1) in Hemiptera (suborder Homoptera), Mecoptera, and Trichoptera, groups previously thought to have only R3. The pattern of R3 occurrence indicates that this retinoid cannot be considered a phylogenetic marker, having a scattered distribution in the class Insecta as well as within some orders of insects. Several environmental factors that might influence the selection of chromophore have been considered, but none correlates with its distribution. The evolutionary reasons for the pattern of occurrence of R3 therefore remain unknown.
Article
1. The bodies of twenty-three nestling blackbirds and twenty-one nestling thrushes were analysed at different ages for water, fat, nitrogen, calcium, phosphorus, sodium, potassium and magnesium. These birds grow from a weight of 5 g at hatching to 70 and 50 g respectively when they leave the nest 12–13 d later. 2. The concentration of N in the bodies doubled, while Ca increased seven to eight times during this period, so that the total amount of Ca in the body increased by about 100 times. 3. The femurs of the newly hatched birds were very immature and contained little Ca or collagen but in the fledgelings the femurs were as well calcified as those of 17-d-old chicks. 4. The gastro-intestinal tracts of the birds contained large amounts of Ca. Their food consists of caterpillars, adult insects and earthworms, none of which have much Ca in their tissues but their gut contents may contain much Ca. It is suggested that it is the gut contents of these invertebrates that provide nestling birds with Ca.
Article
The pathophysiology and lesions associated with vitamin E deficiency are similar between domestic and exotic species, and circulating plasma concentrations are also similar between comparable groups. However, many ecological variables must be considered for the most relevant comparisons. Tissue values of vitamin E, apart from plasma, are unknown for most exotics. Dietary vitamin E requirements of exotic species and domestics appear to differ; based on natural foodstuff analyses and clinical observations, between 50 and 200 mg vitamin E/kg DM are necessary to prevent vitamin E deficiency, 5- to 10-fold higher than current livestock recommendations.
Article
Carotenoid-depleted fruit flies, Drosophila melanogaster, were reared on yeast/glucose medium containing lipid-depleted white corn grits and cholesterol. After rearing for more than a year, the yield of flies remained constant and the content of 3-hydroxyretinal in a head was three logarithmic units less than that of normal flies reared on medium containing yellow corn grits. When all-trans retinal was supplied as the sole source of retinoids, the flies formed and accumulated all-trans 3-hydroxyretinal in the dark. To examine the metabolic pathway to produce (3S)-3-hydroxyretinal in Drosophila, all-trans retinal was supplemented for two hours to carotenoid-depleted flies in the dark, and the subsequent changes in the composition of 3-hydroxyretinal enantiomers were analyzed using a chiral column on HPLC. The results indicated initial formation of (3R)-3-hydroxyretinal followed by isomerization into the 3S enantiomer. In another set of experiments, the membrane fraction was obtained from the head homogenate of retinoid-depleted flies and an in vitro assay of 3-hydroxyretinal formation from retinal was performed. The 3-hydroxyretinal produced was the 3R enantiomer, supporting the result obtained from the in vivo experiment whereby (3S)-3-hydroxyretinal is produced from retinal via (3R)-3-hydroxyretinal. Addition of NADPH enhanced 3-hydroxyretinal formation and the presence of carbon monoxide inhibited it, suggesting that hydroxylation at the C3 position of retinal occurred via the monooxygenase activity of cytochrome P-450.
Article
The eye lenses of the Moroccan day gecko Quedenfeldtia trachyblepharus contain two different pigments: a retinoid (minor pigment) and a carotenoid (major pigment). The retinoid, all-trans 3, 4-didehydroretinol, is bound to iota-crystallin, which comprises only 2% of the total amount of crystallins. The carotenoid is associated to gammas-crystallin - comprising about 10% of total amount of crystallins--and causes the dark yellow colour of the lens. The absorption spectrum of the isolated carotenoid shows a major, triple-peaked band at 372, 392, and 416 nm and two minor peaks at 284 and 294 nm. This spectrum reminds of that of galloxanthin, a carotenoid found in oil droplets of some avian retinae. The absorption spectrum of the carotenoid-gammas-crystallin complex is shifted 6-8 nm bathochromically. In the lens, this complex absorbs ultraviolet and shortwave blue radiation, supposedly improving the optical quality of the dioptric apparatus and protecting the retina against photodamage. Both the retinoid and the carotenoid are present in eye cups. The lenticular carotenoid of Quedenfeldtia is the first example of a carotenoid in the lens of a terrestrial vertebrate with a sufficiently high concentration to be physiologically effective as a UV-filter. Additionally, it is unique in being the first example of a carotenoid associated with gammas-crystallin.
In a colony of 18 green anoles (Anolis carolinensis), 3 animals experienced focally thickened lips, ulcerative cheilitis, lethargy, depression, and weight loss over a 5-month period. In addition to crickets fed fresh fruit and leafy green vegetables, the diet of the green anoles consisted of a supply of mealworms that had been dusted with a commercial liquid vitamin supplement. The history, clinical findings, and histopathologic lesions were suggestive of hypovitaminosis A, which is known to cause squamous metaplasia of the mucus secreting glands and epithelial surfaces in many species.
Article
The performance and blood composition of rats fed housefly larvae meal supplemented with, or without, methionine and lysine, or fed at high concentration were investigated. Rats fed supplemental methionine alone achieved highest body weight gain (P < 0.05). Dietary supplementation of both methionine and lysine or high dietary concentration of larvae meal depressed (P < 0.05) rat feed intake. The blood composition of rats was superior (P < 0.05) on methionine-supplemented larvae meal. Additional amino acids from larvae elicited higher (P < 0.05) serum proteins, cholesterol and triglyceride; however, other blood biochemical profiles were lower (P < 0.05) than in the unsupplemented group. In conclusion, housefly larvae meal seemed deficient in methionine and it benefited the rat tremendously to supplement with this amino acid: however, additional lysine and high dietary inclusion of larvae meal as sole protein source appeared nutritionally inconsequential.
Article
In the animal kingdom, species-specific differences with regard to the absorption of intact carotenoids are observed. The causes of these differences are not entirely understood. To investigate the absorption of selected carotenoids, 20 juvenile green iguanas (Iguana iguana) were fed a carotenoid deficient basal diet for 56 days. Thereafter, the iguanas were assigned to receive a basal diet supplemented with different carotenoids (80 mg/kg diet) such as beta-carotene, canthaxanthin and apo-8'-carotenoic acid ethyl ester for 28 days. Changes in plasma carotinoid concentrations associated with the individual diets were used as indicators of carotenoid absorption. In both the experimental and control groups, only the oxygenated carotenoids (xanthophylls), lutein, zeaxanthin and canthaxanthin, were found in the plasma. Canthaxanthin and apo-8'-carotenoic acid ethyl ester were readily absorbed and recovered from the plasma. However, the supplementation of beta-carotene caused no increase in plasma beta-carotene concentration. Additionally, beta-carotene, canthaxanthin or apo-8'-carotenoic acid ethyl ester did not affect the concentrations of retinol and alpha-tocopherol in plasma. In conclusion, the study demonstrates that iguanas appear to be selective accumulators of polar xanthophylls. The iguana might, therefore, be a valuable model to investigate the selectiveness of carotenoid absorption as well as the function of xanthophylls in animals.
Vitamin D nutri-tional status influences voluntary behavioral photoregulation in a lizard Biologic effect of light 1995 WH,Chen TC, Gut Loading to Enhance Nutrient Content161 rJones LD Composition of mealworm Tenebrio molitor larvae
  • Jr Jones
  • Gw Ferguson
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Jones JR, Ferguson GW, Gehrmann WH, Holick MF, Chen TC, Lu Z. 1996. Vitamin D nutri-tional status influences voluntary behavioral photoregulation in a lizard. In: Holick MF, Jung EG, editors. Biologic effect of light 1995. Berlin: Walter de Gruyter. p 49–55. WH,Chen TC, Gut Loading to Enhance Nutrient Content161 rJones LD, Cooper RW, Harding RS. 1972. Composition of mealworm Tenebrio molitor larvae. J Zoo Anim Med 3:34–41
Official methods of analysis (modified) Nutrient composition of selected whole inverte-brates
  • Aoac
  • International
  • Va Arlington
  • D Barker
  • Fitzpatrick Mp
  • Dierenfeld
  • Es
AOAC International. 1995. Official methods of analysis (modified). 16th ed. AOAC Arlington, VA. Barker D, Fitzpatrick MP, Dierenfeld ES. 1998. Nutrient composition of selected whole inverte-brates. Zoo Biol 17:123–34.
Remarkable differences in the response to dietary vitamin D among species of reptiles and primates: is ultraviolet B light essential?
  • M E Allen
  • O T Oftedal
  • R L Horst
Allen ME, Oftedal OT, Horst RL. 1996. Remarkable differences in the response to dietary vitamin D among species of reptiles and primates: is ultraviolet B light essential? In: Holick MF, Jung EG, editors. Biologic effect of light 1995. Berlin: Walter de Gruyter & Co. p 13-38.
Palm worm (Rhynchophorus palmarum): traditional food in Amazonas
  • Cedra H R Martinez
  • N Briceno
  • L Pizzoferrato
  • P Manzi
  • Ponzetta
  • Marin O Mt
  • Paoletti
Cedra H, Martinez R, Briceno N, Pizzoferrato L, Manzi P, Ponzetta MT, Marin O, Paoletti MG. 2001. Palm worm (Rhynchophorus palmarum): traditional food in Amazonas,
Vitamin D nutritional status influences voluntary behavioral photoregulation in a lizard
  • J R Jones
  • G W Ferguson
  • W H Gehrmann
  • M F Holick
  • T C Chen
  • Z Lu
Jones JR, Ferguson GW, Gehrmann WH, Holick MF, Chen TC, Lu Z. 1996. Vitamin D nutritional status influences voluntary behavioral photoregulation in a lizard. In: Holick MF, Jung EG, editors. Biologic effect of light 1995. Berlin: Walter de Gruyter. p 49-55.
Complete nutrient composition of selected invertebrates commonly fed to insectivores
  • Md Finke