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27
House Cricket Small-scale Farming
ALBERTO COLLAVO
1
, ROBERT H. GLEW
2
, YUNG-SHENG HUANG
3
,
LU-TE CHUANG
3
, REBECCA BOSSE
4
, AND MAURIZIO G. PAOLETTI
1
1
Dept. of Biology, Padova University, Via U. Bassi 58/b, 35121 Padova, Italy
2
Dept. of Biochemistry and Molecular Biology, University of New Mexico School of
Medicine, Albuquerque, NM, USA
3
Ross Products Division, Abbott Laboratories, Columbus, OH, USA
4
NIOSH Laboratory, Cincinnati, OH, USA
Abstract
The potential nutritional value of insects in general and the common house
cricket, Acheta domesticus, in particular in human diets has long been recognized.
In addition to providing a rich source of high quality proteins for human con-
sumption, crickets and other related insects such as grasshoppers and locusts
offer several other advantages as human food sources: they have a short life
span, produce numerous offspring, are amenable to human cultivation, and can
flourish under a wide range of environmental conditions. The main aims of this
study were two: compare the yield of crickets raised on four different diets, and
determine the amino acid, fatty acid, and mineral and trace element content of
crickets grown under the best of these diets. The four diets were: aromatic-arbo-
real (AAD), dairy cow diet (DCD), DCD supplemented with yeast, and human
refuse diet (HRD). The greatest yield (0.45 g per 10 g of feed) and highest sur-
vival (47.5%) of A. domesticus was achieved with HRD when grown for 9 weeks
in 24 hours daylight. The protein content of crickets raised on all four diets ranged
from 56.2 to 60.0% dry weight, and in all cases the essential amino acid score of
the proteins approximated or exceeded the World Health Organization protein
standard. The crickets contained 63–122 mg fatty acid per g dry weight, most of
which was accounted for by palmitic acid, oleic acid, and the two fatty acids
essential for humans, namely linoleic acid and α-linolenic acid. Crickets grown
on any one of the diets contained significant quantities of the following miner-
als or trace elements: calcium (366–480 µg per g dry weight), copper (8.5–9.2 µg
per g), iron (16.2–26.7 µg per g), and magnesium (255–306 µg per g). These data
516 Ecological Implications of Minilivestock
support the contention that crickets contain quantities of many nutrients that
are essential to humans and show that the insect represents a commercially fea-
sible source of food for human populations.
Key Words: Acheta domesticus, cricket, minilivestock, small-scale farming, food
web optimization, edible insects, recycling wastes, natural resources, biodiversity,
sustainable farming, food security, nutrients, fatty acids, minerals, amino acids
Introduction
The main purpose of this study was to test the hypothesis that cultivation of the
common cricket, Acheta domesticus (Plate X, 6), might offer human populations
worldwide an economically feasible, sustainable, and nutritionally sound source
of food. Several investigators have simulated large, insect-based production
systems such as Tribolium confusum (Kok et al., 1990), using a variety of food
sources (Larde, 1989). Several non-European human populations use different
species of Orthoptera as a food source in Africa (Malaisse, 2004, this volume),
Australia (Meyer-Rochow and Changkija, 1997) Latin America, (Onore, 1997;
Ramos-Elorduy 1997; Ruddle, 1973), and North America (Menzel and D’Aluisio,
1998).
The high nutrient quality of the proteins of Acheta domesticus (L.) is widely
recognized. For example, Nakagaki and coworkers (1987) demonstrated that
crickets are an excellent food source for chicks and Finke and collaborators (1989)
showed that weanling rats grow well on crickets. One of these same research
groups (Finke, 2002) also demonstrated that invertebrates in general are an ex-
cellent food source for raising various insectivores. Furthermore, protein com-
monly accounts for as much as 60% dry weight of invertebrates (DeFoliart, 1992).
This study sought to identify a food source that would be suitable for rais-
ing crickets in an economically feasible and environmentally sensitive and sus-
tainable manner. Four different insect diets were compared: (1) an aromatic-
arboreal diet (AAD), (2) a dairy cow diet (DCD), (3) the dairy cow diet supple-
mented with yeast (DCD+Y), and (4) a human refuse diet (HRD) (Table 27.1).
The aromatic-arboreal diet was constituted from organic matter found in abun-
dance in the woody/bushy territory of the Mediterranean, from which common
plants with high nitrogen content and bacteriostatic/bactericidal activity were
selected (Fenaroli, 1963). The DCD and DCD + Y diets were based largely on
cereals fed to dairy cows (without the antiobiotics and integrators usually added).
We used yeast as an additive in the DCD-based diet because preliminary stud-
ies had shown that it contains important growth factors (McFarlane et al., 1959;
Patton, 1967) which would enhance cricket yield. The human refuse diet was
selected because of the availability of large quantities of this material and be-
cause of agricultural politics. Other considerations that factored into our choice
of diets were cost, impact on the environment, and sustainability. In comparing
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 517
the various diets used to raise the crickets, we assessed different cricket crowding
conditions and the sustainability of cropping systems to produce the needed feed.
The second specific aim of the study was to compare the nutrient content of
crickets raised on the four diets, with specific attention to essential amino acids,
fatty acids, and mineral and trace elements. Our data identified a diet that sup-
ports a high yield of crickets and that can provide human diets with substantial
quantities of essential nutrients.
Table 27.1: Diet composition (in grams)
Ingredients Aromatic-Arboreal Diet (AAD) grams
False acacia (Robinia pseudacacia) 4.1
Yeast (Saccharomyces cerevisiae) 2.9
Basel (Ocimum basilicum) 1.3
Sage leaves (Salvia officinalis) 1.0
Hazel leaves (Corylus avellana) 0.5
Maple leaves (Acer campestre) 0.2
Sum 10.0
Ingredients Dairy Cow Diet with Yeast (DCD+Y) grams
Soybean flour (Glycine max) 2.07
Lucern (Medicago sativa) 1.78
Corn flour (Zea mays) 1.46
Wheat flour (Triticum durum) 1.31
Yeast (Saccharomyces cerevisiae) 1.15
Sugar beet (Beta vulgaris var. esculenta) 1.13
Silo 1.10
Sum 10.00
Ingredients Dairy Cow Diet (DCD) grams
Soybean flour (Glycine max) 2.26
Lucern (Medicago sativa) 1.97
Corn flour (Zea mays) 1.65
Wheat (Triticum durum) 1.50
Sugar beet (Beta vulgaris var. esculenta) 1.32
Silage corn 1.30
Sum 10.00
Ingredients of Human Refuse Diet (HRD) grams
Fruits and vegetables (peel and leftover) 3.4
Rice and pasta 2.7
Pork and beef meat 1.1
Bread 1.1
Cheese skins 1.1
Yolk 0.6
Sum 10.0
518 Ecological Implications of Minilivestock
Materials and Methods
Organisms
The crickets employed in this study belong to the species Acheta domesticus (L.).
They were purchased from Livefood UK, The Acres, Gills Lane, Rooks Bridge,
Somerset; www.livefood.co.uk. Two colonies of 70 individuals each were reared
to obtain eggs and for a preliminary assessment of food preferences. At the time
of egg hatching, individual organisms of the same day were collected in order to
establish colonies and to measure food preferences, optimal population density,
optimal rearing diets, and protein content and quality. Overall, 18 colonies com-
prised 50 to 250 individuals were established over a period of 18 months. Two of
our aims were to compare the quality of the various feeds in terms of cricket
production and to compare the energy efficiency conversion index (ECI) of our
cricket populations with that reported for more conventional livestock.
Rearing Conditions
Colonies were reared in terrariums 0.50 m × 0.25 m × 0.35 m (total capacity 44
liters) and constructed of glass and wood. Each rearing box was covered with a
0.75 mm metal screen to prevent insects from escaping. The terrariums con-
tained a nesting box (10 cm × 10 cm × 10 cm) filled with a mixture of sand, earth,
and peat. Four egg cardboards to increase the walking surface were also settled
inside the terrariums, together with test tubes filled with water to ensure hu-
midity and a 25-watt lamp to ensure light and to maintain a suitable tempera-
ture (30.5°C). The crickets were exposed to 24 hours of light to optimize produc-
tivity, as suggested by Comby (1991) and Nakagaki and DeFoliart (1991). A.
domesticus were fed ad libidum water and dry, finely ground feed. The period of
observation was between 2 and 3 months for each colony.
During the rearing time, crickets were periodically counted and weighed to
determine the extent of crowding and growth rates.
Assessment of Feed Preferences
Two colonies per diet were established to conduct a preliminary test of feed
preference. Fifty newly hatched crickets of the same age were used to initiate
each colony. We chose to use relatively few individuals so as to provide optimal
access to food and water and to minimize crowding that might elicit abnormal
behavior. Finely ground feed was given to prevent rotting and to optimize hy-
gienic conditions. The feeds were oven dried at 90°C for 48 hours, then finely
ground before placing in the terrariums. Feed consumption was monitored over
a 60-day period, offering 40 different foods in groups of 16 substrates, and chang-
ing them randomly every 5 days; that is, each group of foods was left in the
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 519
colony for 5 days. Accordingly, we were able to make 192 measurements, testing
each food at least four times, most of them five times. Food consumption was
expressed as the difference between the offered and unconsumed foods over a
five-day interval. We noticed that approximately 10% of the offered food was
dispersed in the box; this loss was measured when the terrariums were cleaned
at the end of each week and taken into consideration when food consumption
was calculated.
Feed Consumption, Efficiency Conversion Index (ECI), and Mortality
Thirteen colonies, each starting with 250 individuals, were grown to test these
diets. Every 2–3 days cricket diet consumption was measured as just described
to ascertain “feed preferences”. Based on these measurements, efficiency con-
version and mortality were determined.
The conversion efficiency of ingested feed was calculated according to
Waldbauer (1968): ECI = 100 * [biomass gained/feed consumed]. At least 30
crickets where taken randomly and weighed. Mortality was recorded as de-
crease in population in each colony on the day of weighting.
Nutritional Value
The amino acid, fatty acid, and mineral and trace element composition of the
adult insects, their diets, and their excreta were analyzed. The insects were col-
lected when the population was 60 days old; however, one day before collec-
tion, they were starved for 24 hours to eliminate gut content. The specimens
were finely dissected and lyophilized for three days. They were then finely pul-
verized using a ceramic mortar and liquid nitrogen, and again lyophilized until
a constant weight was achieved. The powdered samples were stored at –80°C.
The cricket excreta deposited over a period of one month were collected
from the cardboard containers in the breeding boxes. Most of this waste was
made up of feed and spermatophores. The excrement samples were then dried
at 60°C for 5 days, like the four diets offered during the period of breeding.
Protein Content and Amino Acid Composition
The amino acid pattern of the dietary protein source has a marked influence on
the utilization of feed protein by organisms. The basis of this paradigm is that
the need for protein is explained in terms of a need for individual amino acids,
some of which are indispensable and must be supplied in the diet, the rest re-
quiring only a dietary source of nitrogen and carbon skeletons from which cel-
lular synthesis can occur. Furthermore, it is implicit in this paradigm that the
magnitude of the need for the indispensable amino acids (IAA) is such that dif-
ferent proteins fed at isonitrogenous intakes may vary in ability to satisfy the
520 Ecological Implications of Minilivestock
dietary need for protein. Thus, dietary proteins can be classified in terms of
their quality, a function of their amino acid pattern. The consequence of this
approach is that nutritional adequacy is likely to be met by feed in which the
overall amino acid pattern is optimized by complementation, i.e., balancing in-
adequacies in one protein with abundance in others, to achieve an overall pat-
tern which matches needs. In this respect, traditional feed intake practices that
provide a satisfactory supply of most micronutrients also do the same for di-
etary protein (Milt-Ward et al., 1992).
The “chemical index” (CI) shall mean the lowest of the ratios between the
quantity of each essential amino acid of the test protein and the quantity of each
corresponding amino acid of the reference protein. To calculate CI it is necessary
to analyze the feed protein for its nitrogen content. Protein content is calculated
by multiplying the nitrogen content by 6.25 and the feed protein analyzed to
determine its IAA content. The CI is calculated by dividing the milligrams of a
particular IAA in one gram of the test protein by the milligrams of the indis-
pensable amino acids in one gram of the reference protein which is the amino
acid requirement pattern for a 2- to 5-year-old child. The quality of proteins
refers to the CI, that is, the essential amino acid of the sample and the FAO
pattern ratio (FAO/WHO, 1991).
To determine the chemical index, the protein was first hydrolyzed to yield
individual amino acids and these amino acids then analyzed. Techniques for
determination of amino acids were performed according to methods described
in the literature (Bidlingmeyer et al., 1984; Cohen et al., 1988; Hariharan et al.,
1993; Hirs, 1967; Hugli and Moore, 1972).
Chemical Index =
Essential amino acid content of sample
(mg/g protein)
Pattern FAO amino acid in mg/g
×
10
0
An amino acid with a CI less than 100 is considered falling below the stan-
dard for that amino acid.
Fatty Acid Composition
Fatty acid content was determined according to methods described by Cham-
berlain et al. (1993) and Morrison and Smith (1964), and as specified by Paoletti
et al. (2003).
Trace Element and Mineral Analysis
The insects, diets, excreta, and specimens were dried in a vacuum desiccator
until a constant weight was obtained. Portions (approximately 0.2 g) were
weighed into 125 ml beakers and wet-ashed using 10 ml concentrated nitric acid
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 521
and 1 ml perchloric acid. The samples were covered with watch glasses and
allowed to reflux overnight at 150ºC. The next morning they were taken to near
dryness at 150ºC. Samples that retained a darker color or showed remaining
residue were treated with 1 mL of 4:1 nitric/perchloric acids and redigest. They
were cooled and diluted to 10 mL in 4% nitric acid/1% perchloric acid. Sample
solutions were analyzed for trace metal content by ICP-AES (optical emission
spectrometry with inductively coupled plasma). This digestion technique does
not dissolve any siliceous material in the samples.
Since the calcium content of some samples was out of the analytical range,
some of the specimens had to be diluted and reanalyzed. Even with this second
analysis, however, several samples remained outside the analytical range for
calcium. In some cases the sample supply was depleted so a third dilution and
analysis could not be completed; hence the calcium content was reported as
> 2.5%.
Elements reported as n.d. were below the limit of detection. The limit of
quantitation was 3.33 times the limit of detection.
Results
Rearing
Under the rearing conditions of 30.5°C and 24 h light, eggs hatched in 13 days
and the adult stage was usually reached in 45 days; thus, the egg-adult cycle
span was about 57 days. It is noteworthy that mortality was greatest during the
first three molts (until day 9–10 at 30°C).
In comparing the average weight gained using the different diets (Fig. 27.1),
it is apparent that the best growth rate was obtained with the human refuse diet.
In one month crickets fed the HRD had doubled in weight and reached maxi-
mum weight (0.45 g per cricket) in 9 weeks. Other diets in order of performance
vis-à-vis growth of the cricket population were DCD + Y (0.43 g per cricket),
DCD (0.40 g per cricket) and AAD for which the mean weight at 10 weeks was
0.35 g per cricket.
In terms of survival, determined on day 61, the following data were ob-
tained: for the colonies fed on ADD survival was 24%, DCD + Y 43.2%, DCD
27.1%, and HRD 47.5% (Fig. 27.2).
With the DCD + Y the optimum period for collecting crickets for consump-
tion was between 9 and 10 weeks; for the HRD, the highest cricket yields were
obtained at 8–9 weeks.
ECI Obtained with Human Refuse Diet
Rearing crickets using the HRD was more efficient with respect to time
and weight gain than were the other diets. For this reason, we decided to
522 Ecological Implications of Minilivestock
Fig. 27.1: Acheta domesticus, average weight gained using different diets (AAD—Aromatic-Arbo-
real Diet; DCD+Y—Dairy Cow Diet with Yeast; HRD—Human Refuse Diet; DCD—Dairy Cow
Diet.
Fig. 27.2: Acheta domesticus, average mortalities in rearing colonies given different diets (AAD—
Aromatic-Arboreal diet; HRD—Human Refuse Diet; DCD+Y—dairy Cow diet with Yeast; DCD—
Dairy Cow Diet).
0
.000
0.100
0.200
0.300
0.400
0.500
0.600
1 6 11 16 21 26 31 36 41 46 51 56 61 66 71 76 81
Age in day
s
weight in grams
AAD
HRD
DCD+Y
DCD
0
50
100
150
200
250
300
1
8
15
22 29
36
43
50
57
64
71 78 85 92
99
Day
s
Populatio
n
AAD
DCD+Y
DCD
HRD
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 523
concentrate our efforts in carefully assessing feed input, mortality, and weight
in three colonies raised using the human refuse diet. The three colonies were
each composed of 50 individuals and data collected for 10 weeks, as shown in
Fig. 27.3. From these data we obtained an ECI of 64-65 at week 8 (potentially
best harvesting time) as reported in Table 27.11 (see “Discussion” for more
details).
Protein and Amino Acid Content
Table 27.2 is a summary of the amino acid content of crickets raised under three
different conditions; data for insects raised on the DCD cow diet (without yeast
supplement) are not shown due to lack of exemplars at the time of analysis. Also
included in this Table are the amino acid contents of the excreta and various
diets. Overall, the differences in the contents of the various amino acids in the
crickets were small among the three diets. The limiting amino acid (Table 27.3)
was leucine for those raised on the AAD and leucine and lysine for the HRD. No
essential amino acid was limiting in the case of crickets fed the DCD.
Fatty Acid Content
Table 27.4 summarizes the results of fatty acid analyses (expressed in µg g
–1
dry
sample) of the total lipid fraction of the crickets raised on the three diets. The
fatty acid fractions were rich in polyunsaturated fatty acid with a polyunsatu-
rated/saturated ratio close to the recommended diet intake (stated as 1;
Fig. 27.3: Average density of population, weight, and feed consumption in colonies raised on Hu-
man Refuse Diet.
0
10
20
30
40
50
60
0,000
0,100
0,200
0,300
0,400
0,500
0,600
0,700
0,800
density of pop.
weight
food consumption
60
50
40
30
20
10
0
10 17 24 31 38 45 52 59 66
0.100
0.200
0.000
0.300
0.400
0.500
0.600
0.700
0.800
density of pop.
weight
food consumption
Days
Population
Grams
524 Ecological Implications of Minilivestock
Table 27.2: Mean amino acid composition of Acheta domesticus (mg g
–1
sample) and SD; AAD, aromatic-arboreal diet, DCD, dairy cow diet and HRD,
human refuse diet
Amino acid A. domesticus A. domesticus A. domesticus Excrement Excrement Excrement Diet Diet Diet
AAD DCD HDR AAD DCD HDR AAD DCD HDR
(n=3) (n=3) (n=3) (n=3) (n=3) (n=3) (n=3) (n=3) (n=3)
Asp 71.5 ± 7.3 67.3 ± 7.3 63.1 ± 5.8 5.5 ± 1.3 7.5 ± 3.5 6.2 ± 2.1 20.9 ± 0.4 27.5 ± 1.8 22.3 ± 0.4
Glu 86.5 ± 4.0 86.4 ± 7.1 83.8 ± 1.3 11.4 ± 2.3 12.3 ± 2.8 13.0 ± 2.3 17.3 ± 0.8 43.5 ± 0.6 60.2 ± 0.7
Ser 33.1 ± 2.6 32.0 ± 1.3 29.7 ± 1.0 5.1 ± 0.5 5.8 ± 1.5 6.2 ± 2.4 11.6 ± 0.0 10.6 ± 0.1 12.7 ± 0.1
Gly 27.9 ± 1.6 29.3 ± 1.5 28.4 ± 1.3 12.2 ± 1.6 12.5 ± 4.4 10.1 ± 1.8 8.1 ± 0.1 7.9 ± 0.1 6.7 ± 0.1
His 17.2 ± 0.6 17.4 ± 0.7 16.5 ± 0.5 3.1 ± 0.6 3.5 ± 0.2 3.5 ± 0.7 6.9 ± 0.2 6.4 ± 0.1 7.4 ± 0.1
Arg 41.3 ± 0.7 42.8 ± 1.6 39.6 ± 0.9 5.0 ± 0.6 4.7 ± 2.4 5.5 ± 2.2 13.6 ± 0.00 12.5 ± 0.3 10.5 ± 0.2
Thr 23.4 ± 0.3 24.9 ± 1.2 22.8 ± 2.0 5.2 ± 0.6 4.0 ± 1.2 3.4 ± 0.4 8.6 ± 0.0 8.9 ± 0.1 9.5 ± 0.1
Ala 46.6 ± 2.7 48.0 ± 2.7 45.8 ± 4.9 6.6 ± 0.4 10.3 ± 6.7 9.2 ± 4.0 10.6 ± 0.1 10.9 ± 0.1 9.1 ± 0.2
Pro 33.9 ± 1.2 34.2 ± 1.2 33.0 ± 1.5 6.1 ± 0.5 6.7 ± 2.2 6.9 ± 1.5 11.9 ± 1.0 13.3 ± 0.2 17.9 ± 0.4
Tyr 28.1 ± 3.3 24.9 ± 1.5 22.2 ± 2.3 3.2 ± 0.2 3.6 ± 1.1 3.5 ± 1.8 7.7 ± 0.1 6.9 ± 0.1 8.7 ± 0.6
Val 35.1 ± 0.7 35.6 ± 1.2 33.3 ± 1.8 6.3 ± 0.4 6.6 ± 1.9 6.3 ± 1.7 12.3 ± 0.1 11.6 ± 0.0 12.7 ± 0.2
Ile 24.1 ± 0.3 24.8 ± 1.2 22.3 ± 1.1 4.4 ± 0.3 4.5 ± 2.1 4.3 ± 1.5 8.4 ± 0.1 8.4 ± 0.0 9.3 ± 0.2
Leu 38.2 ± 0.5 39.7 ± 2.1 36.1 ± 1.2 6.5 ± 0.4 6.5 ± 2.7 6.2 ± 1.8 12.3 ± 0.0 15.3 ± 0.0 16.9 ± 0.1
Phe 20.4 ± 0.6 21.8 ± 0.9 20.0 ± 0.4 4.8 ± 0.3 3.8 ± 1.1 3.8 ± 0.7 11.3 ± 0.1 10.9 ± 0.1 11.2 ± 0.1
Lys 33.8 ± 0.9 34.6 ± 1.5 31.8 ± 0.2 6.5 ± 1.1 4.3 ± 1.4 4.8 ± 1.1 12.3 ± 0.1 10.9 ± 0.2 13.9 ± 0.1
Trp 7.1 ± 1.2 7.9 ± 0.8 7.5 ± 0.7 2.3 ± 0.3 1.8 ± 1.2 1.3 ± 0.2 4.3 ± 0.3 3.7 ± 0.4 3.0 ± 0.1
Cys 15.6 ± 2.4 14.0 ± 1.2 12.0 ± 0.9 3.7 ± 1.1 4.7 ± 1.0 3.3 ± 0.4 5.8 ± 0.4 7.2 ± 0.3 4.0 ± 0.1
Met 16.3 ± 1.5 14.0 ± 0.7 13.6 ± 0.4 2.6 ± 0.4 3.3 ± 1.1 2.0 ± 0.2 6.0 ± 0.2 4.5 ± 0.2 6.9 ± 0.0
Sum 600.1 599.0 561.7 100.2 105.7 99.9 189.6 221.0 242.6
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 525
FAO/WHO, 1991). Among the various colonies, the best fatty acid quality was
provided by crickets fed the DCD (Table 27.5). The differences in quantities of
saturated and unsaturated fatty acid present in A. domesticus, rearing diet, and
excreta are reported in Fig. 27.4.
Mineral Content
The results of mineral analysis are shown in Table 27.6. Calcium content of crickets
is higher than conventional food such as salmon, pig, or beef. The
calcium:phosphorus ratio of the crickets fed the dairy cow diet was 1.0:4.4, the
human refuse diet 1.0:6.4, and the aromatic-arboreal diet 1.0:1.54. The iron content
of crickets was relatively high, especially in colonies reared on the DCD, with
values similar to those for beef; Table 27.6 reports a higher iron content for frogs.
Table 27.3: Chemical index of proteins in AAD, DCD, and HRD
A. domesticus A. domesticus A. domesticus
AAD DCD HRD
His 151 153 155
Ile 143 148 142
Leu 96 100 97
Lys 97 100 97
Cys+Met 213 187 182
Phe+Tyr 128 124 119
Thr 114 122 119
Trp 107 114 127
Val 167 170 169
Fig. 27.4: Percent of saturated and unsaturated portions of fatty acid in samples.
(Legends Fig. 27.1)
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
Diet AAD
A. domesticus AAD
Excrement AAD
Diet DCD
A. domesticus DCD
Excrement DCD
Diet HRD
A. domesticus HRD
Excrement HRD
SATURATED MONOUNSATURATED POLYUNSATURATED
Diet AAD
A. domesticus AAD
Excrement AAD
Diet AAD
A. domesticus AAD
Excrement AAD
Diet AAD
A. domesticus AAD
Excrement AAD
526 Ecological Implications of Minilivestock
Table 27.4: Mean composition of fatty acid in Acheta domesticus, in collected excrement, and in diet offered—with SD. Values reported as µg g
–1
of dry
weight
Fatty acid A. A. A. Excrement Excrement Excrement Diet Diet Diet
domesticus domesticus domesticus AAD DCD HRD AAD DCD HRD
AAD DCD HRD (n=3) (n=3) (n=3) (n=1) (n=1) (n=1)
(n=3) (n=3) (n=3)
Saturated
C12:0 Lauric acid 0.26 0.08 0.16 ± 0.00 ND ND 0.06 ± 0.04 N.D 0.01 1.02
C14:0 Myristic acid 0.45 ± 0.07 0.58 ± 0.16 2.96 ± 1.45 0.17 ± 0.09 0.04 ± 0.02 1.12 ± 0.14 0.15 0.05 5.31
C15:0 Pentadecanoic acid 0.22 ± 0.06 0.15 ± 0.02 0.46 ± 0.21 0.04 ± 0.02 0.02 ± 0.01 0.15 ± 0.01 0.024 0.02 0.58
C16:0 Palmitic acid 21.18 ± 3.88 22.07 ± 3.92 31.82 ± 10.73 1.21 ± 0.35 0.68 ± 0.08 5.13 ± 0.54 1.84 6.02 23.26
C18:0 Stearic acid 6.05 ± 0.71 8.04 ± 1.43 8.87 ± 2.26 0.39 ± 0.13 0.25 ± 0.02 1.64 ± 0.17 0.30 1.59 6.20
C20:0 Eicosanoic acid 0.19 ± 0.04 0.27 ± 0.01 0.23 ± 0.06 0.06 ± 0.02 0.02 ± 0.00 0.06 ± 0.00 0.05 0.12 0.18
C22:0 Behenic acid 0.04 0.07 ± 0.04 0.06 ± 0.04 0.05 ± 0.01 0.02 ± 0.00 0.02 ± 0.01 0.03 0.10 0.07
C24:0 Lignoceric acid ND ND ND 0.03 ± 0.01 0.01 ± 0.00 ND N.D 0.03 ND
Subtotal 28.39 31.27 44.56 1.95 1.042 8.18 2.40 7.94 36.62
Monounsaturated
C14:1 Myristoleic acid 0.03 ± 0.01 0.05 ± 0.01 0.18 ± 0.12 0.02 ± 0.01 0.01 ± 0.00 0.05 ± 0.01 0.01 0.02 0.39
C16:1 Palmitoleic acid 3.93 ± 1.05 0.63 ± 0.14 2.22 ± 0.79 0.72 ± 0.28 0.11 ± 0.07 0.21 ± 0.06 0.24 0.18 1.48
C18:1
ωω
ωω
ω9 Oleic acid 16.62 ± 2.80 18.96 ± 1.94 29.56 ± 10.16 1.46 ± 0.52 1.15 ± 0.16 3.00 ± 1.07 1.14 9.32 27.33
C18:1
ωω
ωω
ω7 Vaccenoic acid 0.47 ± 0.12 1.01 ± 0.14 1.50 ± 0.60 0.15 ± 0.05 0.23 ± 0.05 0.37 ± 0.06 0.12 0.55 1.58
C20:1
ωω
ωω
ω9 D11-Eicosenoic acid 0.09 ± 0.00 0.11 ± 0.02 0.18 ± 0.02 0.06 ± 0.04 0.03 ± 0.01 0.44 ± 0.06 0.02 0.07 0.18
C20:1
ωω
ωω
ω7 D13-Eicosenoic acid 0.04 ± 0.01 0.05 ± 0.01 0.11 ± 0.05 0.02 ± 0.01 0.01 ± 0.00 0.04 ± 0.02 0.02 0.01 0.02
C22:1
ωω
ωω
ω9 Euric acid 0.05 ± 0.03 0.11 ± 0.01 0.08 ± 0.01 0.07 ± 0.02 0.06 ± 0.04 0.05 ± 0.01 0.12 0.03 0.02
C24:1 Nervonic acid 0.17 0.12 ± 0.08 0.05 ± 0.02 0.04 ± 0.02 0.02 ± 0.01 0.02 ± 0.01 N.D ND ND
Subtotal 21.39 21.03 33.87 2.54 1.62 4.18 1.65 10.19 31.00
Polyunsaturated
C18:2
ωω
ωω
ω6 Linoleic acid 18.97 ± 2.74 39.11 ± 3.09 20.15 ± 2.92 0.40 ± 0.13 0.98 ± 0.06 0.60 ± 0.26 0.93 21.50 5.87
C18:3
ωω
ωω
ω6 γ-Linolenic acid 0.03 ± 0.00 ND 0.05 ± 0.01 ND ND ND 0.01 ND 0.03
C18:3
ωω
ωω
ω3 α-Linolenic acid 3.71 ± 0.71 2.91 ± 0.31 1.39 ± 0.69 0.75 ± 0.28 0.13 ± 0.01 0.09 ± 0.02 3.46 3.13 0.88
Table 27.4: (Contd.)
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 527
Table 27.5: Saturated and unsaturated fractions of fatty acid in Acheta domesticus, excrement, and diets (in %)
Acheta domesticus Excrement Diets
AAD DCD HRD AAD DCD HRD AAD DCD HRD
Saturated 39.1 33.0 43.9 34.6 27.4 63.0 28.3 18.6 49.0
Monounsaturated 29.4 22.2 33.2 44.7 42.8 31.5 19.5 23.8 41.5
Polyunsaturated 31.5 44.8 22.9 20.7 29.8 5.5 52.2 57.6 9.5
Pol./Sat. ratio 0.81 1.36 0.52 0.60 1.09 0.09 1.84 3.10 0.19
Table 27.4: (Contd.)
Fatty acid A. A. A. Excrement Excrement Excrement Diet Diet Diet
domesticus domesticus domesticus AAD DCD HRD AAD DCD HRD
AAD DCD HRD (n=3) (n=3) (n=3) (n=1) (n=1) (n=1)
(n=3) (n=3) (n=3)
C20:2
ωω
ωω
ω6 D11,14-eicosadienoic acid 0.05 ± 0.03 0.05 ± 0.01 0.10 ± 0.03 0.01 ± 0.01 0.01 ± 0.00 0.02 ± 0.01 0.01 0.02 0.08
C20:3
ωω
ωω
ω6 Dihomo-g-linolenic acid ND ND 0.06 ± 0.02 ND ND 0.01 ± 0.00 N.D ND 0.06
C20:4w6 Arachidonic acid ND 0.09 0.33 ± 0.05 ND 0.01 ± 0.00 0.02 ± 0.01 N.D ND 0.16
C20:5
ωω
ωω
ω3 Timnodonic acid ND ND 0.13 ± 0.06 0.02 ± 0.01 0.01 0.01 N.D ND 0.02
C22:4
ωω
ωω
ω6 Adrenic acid ND ND ND ND ND ND N.D ND 0.02
C22:5
ωω
ωω
ω6 D4,7,10,13,16- ND ND ND ND ND ND N.D ND ND
docosapentaenoic acid
C22:5
ωω
ωω
ω3 D7,10,13,16,19- ND ND ND ND ND ND N.D ND 0.03
docosapentaenoic acid
C22:6
ωω
ωω
ω3 Clupanodonic acid ND ND ND ND ND ND N.D ND ND
Subtotal 22.76 42.15 22.21 ± 3.77 1.17 1.13 0.75 4.42 24.65 7.13
Total fatty acid 72.23 94.29 100.53 5.66 3.79 13.10 8.47 42.78 74.75
ND: Absence of values means they were not detectable by analysis.
528 Ecological Implications of Minilivestock
Table 27.6: Mineral content in A. domesticus and other food; AAD, aromatic-arboreal diet, DCD, dairy cow diet and HRD, human refuse diet, results
reported as µg/gram of element per sample
Ag n.d. n.d. n.d. — — — — — — — — — — — — — — —
Al 9.86 12.58 10.72 — — — — — — — — — — — — — —
As 0.01 0.08 0.07 — — — — — — — — — — — — — — —
Ba 0.37 0.56 0.27 — — — — — — — — — — — — — — —
Be 0.02 0.02 0.01 — — — — — — — — — — — — — — —
Ca 480 366 384 407 275 270 380 330 880 200 50 80 40 40 150 300 240 120
Cd 0.01 0.02 0.04 — — — — — — — — — — — — — — —
Co 0.02 0.02 0.01 — — — — — — — — — — — — — — —
Cr 0.68 1.02 0.68 — — — — — — — — — — — — — — —
Cu 9.2 8.7 8.5 6.2 5.1 — 7 2 12 — 0.9 1.3 2 0.8 3.1 4 1.8 —
Fe 19.5 26.7 16.2 19.3 21.2 7 12 18 58 60 6 8 39 19 24 36 8 10
K 2,812 2,589 2,642 3,470 3,520 3,100 3,600 6,300 3,200 — 3,000 2,900 3,310 3,300 2,870 4,940 920 200
La 0.06 0.04 n.d. — — — — — — — — — — — — — — —
Li 0.02 0.04 0.01 — — — — — — — — — — — — — — —
Mg 306 267 255 337 226 — 210 100 440 — 240 170 290 200 1200 1600 200 —
Mn 6.1 8.0 4.6 11.5 8.9 — — — — — — — — — — — — —
Mo 0.21 0.40 0.17 — — — — — — — — — — — — — — —
Na 2,045 2,376 2,474 1,340 1,350 980 1,300 660 2,900 — 620 560 740 410 350 — 50 40
Ni 0.16 0.32 0.13 — — — — — — — — — — — — — — —
P 2,605 1,607 2,442 2,950 2,520 2,800 2,640 2,150 2,360 4,300 1,600 1,600 2,310 2,000 2,560 3,300 940 120
Pb 0.20 0.06 0.08 — — — — — — — — — — — — — — —
Sb 0.83 n.d. n.d. — — — — — — — — — — — — — — —
A. domesticus AAD
A. domesticus DCD
A. domesticus HRD
A. domesticus (adult)
1
A. domesticus (nymph)
1
Salmon (Salmo salar)²
Mackerel (Scomber
scombrus)²
Sardines (Sardina
pilchardus)²
Mussel (Mytilus edulis)²
Frog (Rana esculenta)²
Chicken (Gallus gallus)²
Pig (Sus scrofa
domestica)², beef
Horse (Equus cabalus)²
Adult bovine (Bos
taurus)², filet
Corn (Zea mays)²
Wheat (Triticum durum)²
Rice (Oryza sativa)²
Tapioca (Manihot
esculenta)²
Table 27.6: (Contd.)
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 529
Se n.d. n.d. n.d. 0.19 0.1 — — — — — — — — — — — — —
Sr 1.25 0.71 0.80 — — — — — — — — — — — — — — —
Te n.d. 0.11 n.d. — — — — — — — — — — — — — — —
Ti 0.10 0.14 0.09 — — — — — — — — — — — — — — —
Tl 0.16 n.d. 0.21 — — — — — — — — — — — — — — —
V 0.01 0.01 0.01 — — — — — — — — — — — — — — —
Y 0.01 0.01 0.01 0.21 0.28 — — — — — — — — — — — — —
Zn 61.4 52.7 65.8 67.1 68.0 — — 20 8 22 10.8 16 37.2 28 22.1 29 13 —
Zr 0.06 0.04 0.06 — — — — — — — — — — — — — — —
1
Finke, 2002. Values for commercially raised crickets. Data are expressed on an is basis.
²Carnovale E. and Marletta L. 2000. Composizione degli alimenti. Istituto Nazionale di Ricerca per gli alimenti e la nutrizione.
n.d. = non detectable
— = not reported
Table 27.6: (Contd.)
530 Ecological Implications of Minilivestock
The high sodium content probably reflects NaCl supplementation of the diets.
Silver (Ag), antimony (Sb), selenium (Se), and tellurium (Te) were not detectable.
Discussion
Rearing
From the standpoint of weight gain and survivorship, the best diets with which
to rear crickets appeared to be dairy cow supplemented with yeast, followed
closely by the human refuse diet. The poorest insect yield was obtained using
the aromatic-arboreal diet, attributable largely to the fact that many of the crick-
ets were cannibalized. Apparently the aromatic-arboreal diet was not well-bal-
anced nutritionally and hence the stronger crickets supplemented their alimen-
tation by consuming the weaker ones.
Since magnesium is known to reduce the activity of crustaceans (Morris
and Spicer, 1993) and because it has a narcotic effect that reduces aggression in
molted exemplars (Chouduri and Bagh, 1974), in an effort to reduce cannibal-
ism we added magnesium chloride to the insect drinking water: surprisingly,
magnesium had no effect either on the extent of cannibalism or the insect sing-
ing performances.
From the data gathered, it appears that the best time to collect crickets for
consumption is before they become full adults, that is, at about week 4 or week
5 (Fig. 27.1). Adults, compared with nymphs, have a more coriaceous exoskel-
eton and develop wings. From the standpoint of weight gain, the optimum har-
vesting time was between week 8 and 9.
Chitin
Cricket exoskeleton is partiallly composed of chitin, a biopolymer that cannot
be hydrolyzed by humans lacking the appropriate enzymes. Thus chitin acts
like dietary fiber without offering any calories. So, whole insects as a source of
protein are of somewhat lower quality than vertebrate animal products because
of the indigestibility of chitin (Phelps et al., 1975; Dreyer and Wehmeyer, 1982).
Chitinase, an enzyme that digests chitin, is found in fish (Rehbein et al.,
1986), reptiles, birds (Weiser et al., 1997) insectivorous mammals (Smith et al.,
1998) and cetaceans (Olsen et al., 2000), animals that feed on insects, and crusta-
ceans including krill. Chitinase is also present in association with other enzymes
such as papain and bromelain in some tropical plants, e.g. pineapple (Ananas
comosus), mango (Mangifera indica), and pawpaw (Carica papaya) (Azarkanb et
al., 1987; Subroto et al., 1999) where it seems to perform antimycotic activities.
Apparently in carnivorous Bromeliaceae, most of the enzymes used to release
nutrients contained in animal and vegetal tissues are not secreted directly by the
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 531
plants but produced by the bacteria and saprophytic fungi hosted by them
(Benzing, 1980). Papain and bromelain assist in protein degradation by releas-
ing free amino acids that are ready for absorption and enabling optimization of
fat assimilation.
It would be interesting to study whether consumption of insects combined
with the tropical fruits cited above or other material would lead to chitin soften-
ing or even digestion. According to Goodman (1989), insect chitin has antican-
cer properties. Various studies (Muzzarelli, 1997) report on the successful use of
chitin and derivates in ulcer and lipid absorption.
Diets
Results of the present study indicate that in terms of weight gain and mortality,
the best diet for rearing crickets is the HRD (Fig. 27.2). This indicates that its
nutrient content and balance are superior to those of the other diets.
The great difference in yield of crickets obtained for the two dairy cow diets
led us to speculate that the yeast supplement probably provides the insects with
critical growth factors. The nutritional value of yeast for the growth of insects
has been documented by McFarlane and coworkers (1959) and Patton (1967).
Amino Acid Composition
Except for aspartic acid and tyrosine, both of which are nonessential amino acids,
there were few differences in the amounts of the various amino acids contained
in the crickets raised on the three diets (Table 27.2). With the exception of glutamic
acid, the foods offered to the insects did not vary greatly in their content of the
various amino acids. The Chemical Index (Table 27.3) of each of the three diets
was close to 100 in all samples, thereby indicating these foods contained good-
quality proteins.
Fatty Acid Composition
The amount of fatty acid in the three colonies of crickets was relatively high and
ranged from 6 to 12% dry weight. Good quantities of the two essential fatty
acids, linoleic acid (18:2ω-6) and α-linolenic (18:3ω-3) were present: linoleic acid
at a percentage of 26.24 ± 0.71 in AAD, 41.50 ± 1.30% in DCD, and 20.84 ± 4.09%
in HRD, α-linolenic acid at a percentage of 5.13 ± 0.71 in AAD; 3.08 ± 0.17% in
DCD, and 1.31 ± 0.36% in HRD. These fatty acids represent the substrates for
the synthesis of longer, more unsaturated fatty acids. Usually the major dietary
sources of linoleic acid and α-linolenic acid are polyunsaturated fatty acid-rich
vegetable oils. Recommended dietary intakes of linoleic acid and α-linolenic
532 Ecological Implications of Minilivestock
acid are usually about 3–5% and 0.5% of dietary energy respectively (Ziegler
and Filer, 1996).
Interestingly, arachidonic acid was either absent or present at very low lev-
els in all the cricket specimens, regardless of the food upon which they were
raised. Also absent or lacking were the long-chain polyunsaturated fatty acids,
eicosapentaenoic acid and docosahexaenoic acid in particular. The excreta con-
tained very little fatty acid, indicating that crickets do an efficient job of digest-
ing and absorbing the lipids in their diets.
The polyunsaturated/saturated ratio in the HRD is not close to unit, prob-
ably because the quantities of fat varied in the meat leftovers used in preparing
the diet. This value is confirmed from the high amount of lipid found in the
excreta. Simply reducing the quantity of animal fat in the leftovers used as in-
gredients in preparing the diets should diminish this value.
Minerals and Trace Elements
As mentioned earlier, Table 27.6 compares the mineral and trace element com-
position of A. domesticus with that of some common foods. The quantities of
calcium, copper, and magnesium in the crickets exceeded those of other animals
except mussel. The potassium content of the crickets was slightly lower than in
fish, mollusks, amphibians and other vertebrates. The phosphorus content var-
ied greatly among the crickets grown on the three diets; in general, however, the
crickets contained more phosphorus than some common livestock consumed
by humans. The zinc content of crickets was high and comparable to that re-
ported for other common animal and plant foods (Table 27.6). The relatively
high sodium content of the crickets was likely the result of supplementation of
the diets with sodium chloride, as suggested by other investigators (Nakagaki
et al., 1987; Luckey and Stone, 1968).
ECI Obtained Using the Human Refuse Diet
Total body composition data (Table 27.7) show that crickets have a higher water
content, similar protein content, and significantly less fat than most common
livestock. The ECI for the diets in our trials was much higher than for any of the
vertebrate species, i.e., poultry 1.5 times higher, pig and sheep 2 times higher
and beef 4 times higher. The differences between our results and those of
Nakagaki and DeFoliart (1991) are probably due to differences in insect harvest-
ing times; they harvested at 21 days, we harvested at 45 days.
The favorable conversion efficiency showed by crickets relative to domesti-
cated animals, and by insects in general, is probably due to their unusual physi-
ology; insects do not have to spend energy maintaining body temperature. An-
other advantage of insect breeding is the short span of productive cycle. These
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 533
points should to be taken into consideration in the context of commercial
production.
Environmental Impacts and Diet Sustainability
In breeding crickets using the dairy cow diet, we were able to identify possible
environmental factors related to: tillage (soil erosion, organic soil loss), chemical
fertilizers, insecticides, herbicides and fungicides applications and their poten-
tial effects on nontarget organisms and the environment.
Table 27.8 reports such impacts under conditions of conventional cultiva-
tion. We tried to measure the possible environmental impacts of various crops
under conventional agricultural practices. Activities such as tillage, use of chemi-
cal fertilizers, insecticide, herbicide, and fungicide applications were “weighed”
on the basis of assessed agronomic practices: the “weight” of every activity, ex-
pressed on a scale of 1 to 4 (where 1 represent lowest impact) was summed to
obtain an index of total impact. In this manner we were able to recognize that in
Table 27.7: Comparison of current breeding animals and Acheta domesticus (in vertebrates, entrails
are not included) and ECI
Species and references % Water % Protein % Fat % ECI
A. domesticus
Woodring et al. 1977 68.4 15.0 10.3 —
Nakagaki and DeFoliart, 1991 74.2 — — 92
Finke, 2002 ¹ 73.1 17.9 5.1 —
This work² 72.3 16.3 — 59
Chicken
Ensminger, 1980 64.0 18.8 14.2 —
Meyer and Nelson, 1963 — 28.6 4.9 35
Lovell, 1979 — — — 48
Pig
Ensminger, 1980 50.0 13.0 34.4 —
Meyer and Nelson, 1963 — 12.7 38.0 28
Whittemore & Elsey, 1976 52.6 14.7 29.5 —
Lovell, 1979 — — — 31
Sheep
Ensminger, 1980 53.2 15 29.0 —
Meyer & Nelson, 1963 — 15.2 25.2 18
Beef
Ensminger, 1980 53.5 17.0 26.0 —
Meyer and Nelson, 1963 — 18.2 21.1 16
Berg and Butterfield, 1976 52.0 17.1 26.9 —
Lovell, 1979 — — — 13
¹ Average values of adults and young.
² Colonies fed with human refuse diet.
534 Ecological Implications of Minilivestock
Table 27.8: Environmental impacts of different crops under conventional agricultural practices
Tillage Chemical Fungicides Insecticides Herbicides Total
fertilizers impact
Corn flour (Zea mays) xxx xxxx x xxxx 12
Silage corn (Zea mays) xxx xxx x xxx 10
Soybean flour
(Glycine max) xx x xxx 6
Lucern
(Medicago sativa) x x x 3
Sugar beet (Beta
vulgaris var. esculenta) xxx xxx xx xx xxxx 14
Wheat (Triticum durum) xx xx x x 6
Table 27.9: Annual production of different crops per hectare (ha); 1 q = 100 kg (pers. comm. Prof. G.
Cozzi, 2002)
Lucern (Medicago sativa), hay 13 q/ha;
Corn flour (Zea mays) 120 q/ha;
Silage corn (Zea mays) 800 q/ha;
Soybean flour (Glycine max) 40 q/ha;
Wheat (Triticum durum) 70 q/ha;
Sugar beet (Beta vulgaris var. esculenta) 650 q/ha.
Table 27.10: Resources and cultivable surface needed to produce 1 ton of Acheta domesticus with
dairy cow diet (DCD)
Soybean Lucern Corn Wheat Sugar Silage Total
flour beet corn
Resources needed 6.4 q 5.5 q 4.6 q 4.1 q 3.6 q 3.5 q 27.8 q
Surface needed 1596 m² 425 m² 382 m² 593 m² 56 m² 44 m² 3096 m²
cultivating sugar beet or corn greater impacting activities are involved than in
cultivating alfalfa.
Most of the ingredients used in the diets tested in this work have a low
impact on conventional methods of production and might have an even lower
impact were biological or integrated agriculture were the goal.
An estimate of the resources required to produce 1 ton of A. domesticus us-
ing conventional agriculture is reported in Table 27.9. As for of the yeast-based
diet, we were not able to estimate the environmental cost of cricket production
due to lack of information about yeast production and impacts.
Based on diet consumption, we estimated that 2.78 tons were required to
produce one ton of crickets. The quantities of the various dietary components
and cultivable surface needed to produce one ton of crickets are shown in Table
27.10.
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 535
Hygienic Hazard and Potential Constraints
The vernacular and scientific names of Acheta domesticus suggest infestation of
human dwellings and in the past they were common inhabitants of kitchens,
bakeries, and places where grains and flour were stored; in recent years they
have become rare if not altogether absent, depending largely on the standards
of hygiene acquired by humans. Moreover, insects can be vectors of disease,
spreading various forms of parasite and pathogen: virus, rickettsiae, bacteria,
protozoa, and nematodes (Busvine, 1980).
In this study neither viral and bacteriological susceptibilities of bred A.
domesticus, nor their potential allergenic properties were assessed. Insects, as
arthropods, could present the same problems as shellfish (i.e., shrimp, lobster,
crayfish), which are well known for their ability to induce mild to severe allergic
reactions in susceptible individuals. Thus, this risk should not be taken lightly.
Usually the popular image of insect allergies is that associated with the bites
and stings of venomous species such as bees, ants, and wasps (injectant aller-
gens). More common allergic reactions attributable to insects include those caused
by contacting body parts or waste products (contact allergens) or inhaling mi-
croscopic dust particles composed of pulverized carcasses, cast skins and ex-
creta (inhalant allergens). Allergies caused by contacting or inhaling insect ma-
terial can have significant health consequences in the home or work environ-
ment with symptoms ranging from eczema and dermatitis, to rhinitis, conges-
tion, and bronchial asthma. In severe cases, sensitivity to insect material might
be heightened to the extent that the victim experiences anaphylactic shock, a
potentially life-threatening condition often involving rapid swelling, acute res-
piratory distress, and collapse of circulation (Phillips and Burkholder, 1984).
Since most insect allergies are of the contact and inhalant type, it would be rea-
sonable to assume that the greatest health risk associated with food insects would
be to workers involved in their production. Given the small and obscure nature
of the food insects industry, virtually nothing is known of such problems. A case
has been reported for Bulgaria in which employees working on nuts acquired
eczema and dermatitis due to contact with substances secreted by larvae of Plodia
interpunctella feeding on the nuts (Phillips and Burkholder, 1995).
Reactions to Orthoptera (grasshoppers, crickets, locusts, cockroaches, etc.)
are also common. LeClercq (1969) reported that workers rearing locusts suf-
fered rhinitis, itching skin, bronchitis, and ultimately asthma in general sequence.
Wirtz (1980) recounted one study of migratory locusts where all of the workers
became allergic to the insect. We know of a researcher who suffered dyspnea
(labored breathing) during a prolonged session of grinding crickets into meal to
supplement chicken feed. Three cases of anaphylactic shock involving orthop-
terans were reported by Wirtz. Good ventilation, protective clothing, gloves,
and masks are common sense preventive measures.
Our major interest focused on ingestant allergens, that is, eating or uninten-
tionally swallowing allergenic insect material. Unfortunately direct evidence
536 Ecological Implications of Minilivestock
for allergies to food insects is practically nonexistent. Some insight can be gained
from controlled experiments on human subjects done with preparations of com-
mon food-infesting insects. A classic study by Bernton and Brown in 1967 uti-
lized dialized extracts of seven such insects in skin sensitivity tests of subjects
with and without known allergies. Test extracts included those of the rice wee-
vil (Sitophilus oryzae), fruit fly (Drosophila melanogaster), Indian meal moth (Plodia
interpunctella), saw-toothed grain beetle (Oryzaephilus surinamensis), red flour
beetle larvae and adults (Tribolium castaneum), flour beetle (Tribolium confusum),
and lesser grain borer (Rhyzopertha dominica). Of the 230 allergic patients, 68
(29.6%) reacted positively to one or more of the dialized insect extracts. Surpris-
ingly, of the 194 nonallergic subjects, 50 (25.8%) showed sensitivity to at least
one extract. A total of 333 positive reactions were observed. The degree of over-
all sensitivity was practically the same for both groups, with the Indian meal
moth extract eliciting the most positive reactions followed by extracts of red
flour beetle larvae, red flour beetle adults, rice weevils, fruit flies, confused flour
beetles, saw-toothed grain beetles, and lesser grain borers.
The only reported case of A. domesticus as a vector of diseases in vertebrates
is mentioned for Geopetitia aspiculata, a nematode found in 12 species of
Passeriformes, one species of Charadriiformes and one species of Coraciiformes
which died at the Assiniboine Park Zoo, Winnipeg, Canada. Fortunately, this
nematode is harmless for humans (Bartlett et al., 1984).
There may be processes that can effectively diminish the potential threat of
food allergies. One school of thought suggests that insect allergens in food are
deactivated by cooking, yet when five of the aforementioned insect extracts were
heated at 100°C for one hour, positive skin reactions were still observed, albeit
deemed less vigorous than those of the unheated treatments. In a 1964 study,
Bernton and Brown heat-treated extracts of cockroaches at 100°C for one hour
and found that these allergens resisted deactivation. The idea that insect aller-
gens are deactivated in the highly acidic environment of the stomach is also
appealing until one considers the number of normally eaten foods that have
been identified as potentially allergenic and whose allergens obviously survive
digestion and cooking.
For most people, working with or eating food insects should pose little if
any health risk, especially if they have no history of allergy to insects or other
arthropods. Nonetheless, since sensitivity can be acquired with repeated expo-
sure to an allergen, a measure of vigilance is in order. A person with known
insect or arthropod allergies would be wise to exercise some caution. Cross-
reactivity among related as well as taxonomically dispersed groups of insects
has been established. There is also evidence for cross-reactivity among distantly
related members of Arthropoda, suggesting the existence of common allergens
within the phylum. So, if you are allergic to shellfish, you might want to recon-
sider the idea of eating insects.
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 537
Conclusion
Crickets are a good resource of animal protein, fat, and other nutrients.
Some considerations about costs should be made in cricket breeding. When
a human refuse diet is adopted, the input starts at a level of domestic waste. If
not used, this material represents a cost for waste processing and disposal and a
loss of organic matter. Otherwise, by converting this organic refuse into animal
proteins, the waste becomes a resource (Table 27.11).
Table 27.11: Mean density of population (and SD), fresh weight of A. domesticus, diet consumed,
and Efficiency Conversion Index (ECI) in colonies fed human refuse diet (HRD)
Days of life Density of Weight of Amount of diet ECI
population A. domesticus consumed (in g)
(no. of crickets) (in g)
10 50 ± 0 0.010 ± 0.001
17 48 ± 2 0.019 ± 0.009
24 47 ± 2 0.125 ± 0.013
31 44 ± 1 0.236 ± 0.011
38 43 ± 2 0.266 ± 0.038 0.426 ± 0.039 63 ± 6.11
45 41 ± 3 0.358 ± 0.041 0.605 ± 0.036 59 ± 4.16
52 41 ± 3 0.422 ± 0.026 0.663 ± 0.027 64 ± 2.52
59 36 ± 2 0.451 ± 0.017 0.694 ± 0.022 65 ± 1.73
66 34 ± 3 0.452 ± 0.016 0.721 ± 0.027 63 ± 2.08
Where the dairy cow diet is used, one needs to consider in the production
system costs for agricultural ingredients composing the diet and the relative
costs of herbicides, fungicides, insecticides, and fertilizers causing high envi-
ronmental impacts and potential hazards.
The aromatic arboreal diet does not seem favorable for the low cricket popu-
lation density it can sustain; however it appears environmentally more friendly.
The protein quality and linoleic and a-linolenic acid content of crickets are
high. The fatty acid profiles most likely reflect the fatty acid composition of the
feed, which is commonly seen in monogastric animals (Finke, 2002).
The chitin in crickets presents a problem because of its nondigestibility in
humans, as well other livestock, due to their lack of chitinase. Future studies
should investigate whether this problem can be solved by consuming insects
together with fruits such as Bromeliaceae and Caricaceae that contain enzymes
with an activity similar to chitinase. To reduce the quantity of chitin, insect har-
vesting could be done before the last molt.
Excreta produced during the breeding cycle, still high in nitrogen, can be
used as fertilizer or input for crops.
To purchase crickets, contact: Livefood UK: http://www.livefood.co.uk/
538 Ecological Implications of Minilivestock
References
Azarkanb M., Amranib A., Nijsb M., Vandermeersa A. et al. 1997. Carica papaya latex is a rich
source of a class II chitinase. Phytochem. 46: 1319–1325.
Bartlett C.M., Crawshaw G.J., and Appy R.G. 1984. Epizootiology, development, and pathology of
Geopetitia aspiculata Webster, 1971 (Nematoda: Habronematoidea) in tropical birds at the
Assiniboine Park Zoo, Winnipeg. Canada J. Wildl. Dis. 20: 289–99.
Benzing D.H. 1980. The Biology of Bromeliads. Mad River Press, Eureka, CA, USA, 305 pp.
Bernton H.S. and Brown H. 1964. Insect allergy—preliminary studies of the cockroach. J. Allergy
35: 506–513.
Bernton H.S. and Brown H. 1967. Insects as potential sources of ingestant allergens. Ann. Allergy
25: 381–387.
Bidlingmeyer B.A., Cohen S.A., and Tarvin, T.L. 1984. Rapid analysis of amino acids using precolumn
derivitization. J. Chromatogr. 336: 93–104.
Busvine J.R. 1955. Simple methods for rearing the crickets (Gryllus domesticus L.) with some obser-
vations on speed of development at different temperatures. Proc. R. Ent. Soc. Lond. (A) 30:
15–18.
Busvine, J.R. 1980. Insects and Hygiene. Chapman and Hall, London, 568 pp.
Chamberlain J., Nelson G., and Milton K. 1993. Fatty acid profiles af major food sources of howler
monkeys (Aloutta palliata) in the Neotropics. Experientia 49: 820–823.
Choudhuri D. and Bagh R. 1974. On the sub-social behaviour and cannibalism in Schizodactylus
monstrosus (Orthoptera: Schizodactylidae). Rev. Ecol. Biol. Sol. 11: 569–573.
Cohen S.A. and Strydom D.J. 1988. Amino acid analysis utilizing phenylisotiocyanate derivatives.
Ann. Biochem. 174: 1–16.
Comby B. 1991. Insetti che bontà. Piemme ed. Milano, 158 pp.
DeFoliart G.R. 1992. Insects as human food. Crop Protection, Elsevier, New York, NY, vol. 11, pp.
395–399.
DeFoliart G.R. and Nakagaki B.J. 1991. Comparison of diets for mass-rearing A. domesticus (Ortho-
ptera: Gryllidae) as a novelty food, and comparison of food conversion efficiency with values
reported for livestock. J. Econ. Entomol. 84: 892–896.
Dreyer J.J. and Wehmeyer A.S. 1982. On the nutritive value of Mopanie worms (Sur la valeur nutri-
tive des vers de Mopanie). S. Afr. J. Sci. 78: 33–35.
FAO/WHO. 1991. Report on protein quality evaluation. Paper no. 51, FAO, UN, Rome.
Fenaroli G. 1963. Le sostanze aromatiche. Hoepli Ed., Milano, Italica, vol. 11, 1004 pp.
Finke M.D. 2002. Complete nutrient composition of commercially raised invertebrates used as food
for insectivores. Zool. Biol. 21: 269–285.
Finke M.D., DeFoliart G.R., and Benvenga N.J. 1989. Use of a four-parameter logistic model to
evaluate the quality of the protein from three insect species when fed to rats. J. Nutr. 119: 864–
871.
Goodman W.G. 1989. Chitin, a magic bullet? Food Insects Newsl. 2(3): 1–6.
Hariharan M., Naga S., and VanNoord T. 1993. Systematic approach to the development of plasma
amino acid analysis by high-performance liquid chromatography with ultraviolet detection
with precolumn derivatization using phenyl isothiocyanate. J. Chromatography: Biomed. Appl.
621: 15–22.
Hirs C.W.H. 1967. Performic acid oxidation. Methods Enzymol. 11: 197–199.
Hugli T.E. and Moore S. 1972. Determination of tryptophan content of proteins by ion exchange
chromatography of alkaline hydrolysates. J. Biol. Chem. 247: 2828–2834.
Kok R., Shivhare U.S., and Lomamliza K. 1990. Mass and component balances for insect produc-
tion. Can. Agric. Eng., 185–192
Larde G. 1989. Investigations on some factors affecting larval growth in a coffee-pulp bed. Biol.
Wastes 30: 11–19.
LeClercq M. 1969. Entomological Parasitology. Pergamon Press, New York, NY, 158 pp.
Luckey T.D. and Stone P.C. 1968. Cricket nutrition: supplementation of grass by known nutrients.
J. Insect Physiol. 14: 1533–1538.
Alberto Collavo, Robert H. Glew, Yung-Sheng Huang et al. 539
Malaisse F. 2004. Human consumption of Lepidoptera, termites, Orthoptera, and ants in Africa
(this volume).
McFarlane J.E., Neilson B., and Ghouri A.S.K. 1959. Artificial diets for the house crickets. Can. J.
Zool. 37: 913–916.
Menzel, P. and D’Aluisio F. 1998. Man Eating Bugs. Ten Speed Press, Berkeley, CA, 192 pp.
Meyer-Rochow V.B. and Changkija S. 1997. Uses of insects as human food in Papua New Guinea,
Australia, and North-East India: cross-cultural considerations and cautious conclusions. Ecol.
Food Nutr. 36: 159–185.
Milt-Ward D.J., Newsholme E.A., Pellett P.L., and Uauy R. 1992. Amino acid scoring in health and
disease. In: Protein-Energy Interactions: Proc. Workshop Int. Dietary Energy Consultancy
Group. United Nations Univ. Switzerland. Online. Internet. June 30, 2003. Available
www.unu.edu/unupress/food/foodnutrition.html
Morris D. and Spicer J.I. 1993. A brief re-examination of the function and regulation of extracellular
magnesium and its relationship to activity in crustacean arthropods. Comp. Biochem. Physiol.
106: 19–23.
Morrison W.R. and Smith L.M. 1964. Preparation of fatty acid methyl esters and dimethylacetals
from lipids with boron trifluoride-methanol. J. Lipid Res., 5: 600–608.
Muzzarelli R.A.A. 1997. Human enzymatic activities related to the therapeutic administration of
chitin derivates. Cell. Mol. Life Sci. 53: 131–140.
Nakagaki B.J. and DeFoliart G.R. 1991. Comparison of diets for mass-rearing Acheta domesticus
(Orthoptera: Gryllidae) as a novelty food, and comparison of food conversion efficiency with
values reported for livestock. J. Econ. Entomol. 84 (3): 891–896.
Nakagaki B.J., Sunde M.L., and DeFoliart G.R. 1987. Protein quality of the house cricket, Acheta
domesticus, when fed to broiler chicks. Poult. Sci. 66: 1367–1371.
Onore, G. 1997. A brief note on edible insects in Ecuador. Ecology of Food and Nutrition, 36 (2–4):
277–285.
Olsen M.A., Blix A.S., Utsi T.H.A., Sormo W., and Mathiesen S.D. 2000. Chitinolytic bacteria in the
mink whale forestomach. Can. J. Microbiol. 46 (1): 85–94.
Paoletti M.G., Buscardo E., Vanderjagt D.J., Pastuszyn A. et al. 2003. Nutrient content of termites
(Syntermes soldiers) consumed by Makiritare Amerindians of the Alto Orinoco of Venezuela.
Ecol. Food Nutr. 42: 173–187.
Patton R.L. 1967. Olicidic diets for Acheta domesticus (Orthoptera: Gryllidae). Ann. Entomol. Soc.
Amer. 60: 1238–1242.
Phelps R.J., Struthers J.K., and Mayo S.J.L. 1975. Investigations into the nutritive value of Macrotermes
falciger, Isoptera, Termiditae [Recherches sur la valeur nutritive de Macrotermes falciger, Isoptère
Termiditae]. Zool. Afr. 10: 23–132.
Phillips J.K. and Burkholder W.E. 1984. Health hazards of insects and mites in food. In: Baur F.J.
(ed.). Insect Management for Food Storage and Processing. Amer. Assoc. Cereal Chemists, St.
Paul, MN, pp. 279–292.
Phillips J.K. and Burkholder W.E. 1995. Allergies Related to Food Insect Production and Consump-
tion. USDA-ARS Stored-Product Insects Research Laboratory, vol. 8.
Ramos-Elorduy J. 1997. Insects: a sustainable source of food? Ecol. Food Nutr. 36: 247–276.
Rehbein H., Danulat E., and Leineman M. 1986. Activities of chitinase and protease and concentra-
tion of fluoride in the digestive tract of Antarctic fishes feeding on krill (Euphausia superba,
Dana). Comp. Biochem. Physiol. 85: 545–551.
Ruddle, K. 1973. The human use of insects: examples from the Yukpa. Biotropica, 5: 94–101.
Smith, S.A., Robbins L.W., and Steier J.G. 1998. Isolation and characterization of a chitinase from
the nine-banded armadillo, Dasypus novemcinctus. J. Mammalogy 79: 486–491.
Subroto T., Sufiati S., and Beintema J.J. 1999. Papaya (Carica papaya) lysozyme is a member of the
family 19 (basic, class II) chitinases. J. Molec. Evol. 49: 819–821.
Waldbauer G.P. 1968: The consumption, digestion and utilization of solanaceous and non-solana-
ceous plants by larvae of the tobacco hornworm, Protoparcasxta (Johan.) (Lepidoptera:
Sphingidae). Entomol. Exp. Appl. 7: 253–269.
540 Ecological Implications of Minilivestock
Weiser J.I., Porth A., Mertens D., and Karasov W.H. 1997. Digestion of chitin by Northern Bob-
whites and American robins. Condor 99: 554–556.
Wirtz R.A. 1980. Occupational allergies to arthropods—documentation and prevention. Bull.
Entomol. Soci. Amer. 26: 356–360.
Ziegler E.E. and Filer Jr. L.J. 1996. Present Knowledge in Nutrition. ILSI Press, Washington, DC,
684 pp.
