Insects for animal feeding: A review
Y. Ramana Reddy1* and M. Blümmel2
1
International Livestock Research Institute (ILRI), ICRISAT, Patancheru, India – 502 324
2
International Livestock Research Institute (ILRI), Addis Ababa, Ethiopia
--------------------------------------------------------------------------------------------------------------------------*Corresponding author
Introduction
The food production system of the world is rapidly changing due to growth in human population,
urbanization, nutritional preferences, environmental concerns, growing income and other
anthropogenic pressures. Demand for animal sourced food (ASF) is increasing both quantitatively
and qualitatively. The predicted demand for meat (pork, chicken, beef etc.) and milk in 2050 will be
70 and 58% percent higher compared to 2010 with the bulk of the demand coming from developing
countries with their growing middle classes (FAO 2011a) In addition consumption of ASF in these
countries is still beyond recommended levels for cognitive development and health status
particularly for children. On the other hand livestock farming occupies already 70% of all agricultural
land (Steinfeld et al., 2006), consume 8% of water used by humans (FAO, 2009), contribute 14.5% to
greenhouse gas (equivalent to 7.1 Giga tons of CO2) emissions (Gerber et al., 2012) and causing
much higher water footprint than plan sourced foods (Mekonnen and Hoekstra, 2012). Livestock
production is resource hungry and the available natural resources may not support significant
increased production of ASF. Feed production and feeding play here a key role. Currently important
protein sources for animal feed production are soybean meal and fish meal but availability of land
for soya cultivation is limited and marine over exploitation threatens fish meal production. Hence,
the price of these two feed ingredients has doubled during the last 5 years while already
representing 60-70% of production costs.
Insects have been proposed as a high quality alternative feed for livestock and fish that can
be efficiently and sustainable produced (insects have, of course also be proposed, and are actually
widely used, as a high quality food for humans but this is not the topic of this review) Insect
production on a commercial scale is considered a promising strategy for global feed security
because , insects grow and reproduce rapidly, demand little land (Oonincx and De Boer, 2012), emit
lower greenhouse gases (Oonincx et al., 2010) and ammonia than cattle or pigs and their production
requires low capital investment (FAO, 2013). Insects are also more efficient in converting feed to
protein (Veldcamp et al., 2012) probably due to their poikilothermic physiology and can be reared on
bio-waste streams and to convert waste biomass into high value feed resources Insects as food and
feed can only have a significant impact on food-feed security if they are produced en masse.
Veldcamp et al. (2012) demonstrated production of insects on large scale and use them as an
alternative protein rich feed in pigs and poultry diets. In Thailand 20,000 insect farms produce an
average of 7,500 metric tons in a year for home consumption and for sale in the market
(Hanboonsong et al., 2013). Agriprotein Technologies, Australia is producing two tons maggots as
protein source per week but target is 100 t of larvae per day. In China Hao Cheng Mealworms Inc.
produces 50 tons of living worms per month as feed.
Insect species
More than 2000 edible insect species have been reported in the literature, most of them from
tropical countries. The insect species reported to have the greatest potential as feed on an industrial
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scale are the black soldier fly (Hermetia illucens),the common housefly (Musca domestica) and the
meal worm (Tenebrio molitor), see Veldcamp and Bosch (2015). These three species have great
potential to use and valorize organic waste of which 1.3 billion tons are annually produced globally
(FAO, 2011b) with a potential value of t US $ 750 billion (The Economist, 2014). Oher insects of
importance include locusts-grasshoppers-crickets and silkworm (Table 1). Several review papers and
reports have been published on insects as human food/animal feed (Veldcamp et al., 2012; Makkar
et al., 2014; EFSA Scientific Committee, 2015) reviewed. Based on the available literature and
reviews this paper is focusing on insects for feeding animals addressing insect farming, nutritional
quality, nutritive value, functional properties, animal performance, cost economics , environmental
foot print of insect farming, risk profile of insects, major concerns of insect farming and future
research needed.
Table 1. Order and species and stage of insects used as food and feed for humans and livestock
Order
Scientific name
Common name
Coleoptera
Diptera
Tenebrio molitor
Hermetia illucens
Musca domestica
Bombyx mori
Locusta migratoria
Acheta domestica
Mealworm
Black soldier fly
House fly
Silk worm
Grasshopper
House cricket
Lepidoptera
Orthoptera
Stage at which
harvested for
food/feed
Larvae
Larvae/pupae
Larvae/pupae
Pupae
Adult
Adult
Borroso et al. (2014)
Insect Farming
Insect farming has similar characteristics to that of livestock farming in that insects need
feed (substrate) and water to supply energy and nutrients for maintenance, growth reproduction
and excrete intestinal contents (frass). The production is influenced by the physical conditions (scale
off operation and level of technology used) and the level of biosecurity to prevent contamination
with microorganisms from surrounding environment (waste management units, neighboring farms,
wild life etc.) Usually no hormones, antibiotics or chemicals are used for rearing insects in the
existing farming systems except biocides for disinfection of the production environment in between
batches of insects. The physical conditions and time frame for the hatching eggs to be harvested as
larvae depend on the species. Eggs are introduced on to the substrate either manually, mechanically
or by natural oviposition from adult flies. Table 2 depicts the substrates in use and also under
consideration for use (since some of the substrates are currently under prohibition by EU) for insect
rearing.
Table 2. Substrates approved/under consideration for rearing insects
a. Animal feed materials – feed materials authorized as feed for food producing animals
b. Food produced for human consumption including meat and fish but with expired date or
with defective manufacturing or packing
c. Byproducts from slaughter houses (hides, hair, feathers, bones etc.) originate from animals
d. Food waste of both animal and non-animal origin from restaurants, catering and households
e. Animal manure and intestinal content (pig, poultry, cattle etc.)
f. Other organic wastes of vegetable origin such as from gardening and forest
g. Human manure and sewage sludge
EFSA Scientific Committee, 2015
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The larvae are maintained on the substrate for 1-2 weeks depending on species and also
temperature. In case of meal worms (Tenebrio molitor) it takes 8-10 weeks at temperature of 2830oC and 60% relative humidity to reach the stage for harvest (NVWA, 2012). For black soldier fly (H.
illucens) the time will be approximately 12 days. Black soldier flies (BSF) are naturally found in cattle,
poultry and pig manure but can also be reared on organic waste such as vegetables, catsup, carrion,
coffee bean pulp and fish offal. The survival rate of larvae on pig, poultry and cow manure was 97,
82 and 88%, respectively indicating suitability of diverse manure for rearing BSF. In closed bovine
facilities, BSF larvae reduced available P and N by 61-70 and 30-50%, respectively (Newton et al.,
2008) in manure. In swine manure N and P are reduced by 71 and 52%, respectively by BSF larvae
digestion. The larvae can also modify the microflora by reducing pathogenic bacteria such as
Escherichia coli O157:H7 and Salmonella enterica in cow and hen manure (Ericson et al., 2004; Liu et
al., 2008). Culturing BSF in manure solids separated from swine waste (mix of manure solids, urine
and excess water) by conveyor belt or directly beneath pigs housed on slatted floors in high-rise
buildings by diverting/draining urine and spilled water yield 0.214 and 0.153 kg larvae/pig/d
(Newton et al., 2005). They can feed quickly from 25 mg to 500 mg larvae (fresh)/d. Average
prepupal collections would be 64 t per year from a finishing house of 1000 heads with 2.5 turns of
pigs/year. BSF system developed by Sheppard et al. (1998) reduced manure volume by 50% and
nitrogen concentration by 24% (62% reduction of N mass). BSF requires warm environment
(oviposition occurs at 27.5-37.5oC) for biodegradation. Development time for BSF is 10-31 days
under optimum conditions but may go up to 4-7 months with additional 2 weeks for pupae stage
development. The type, quantity and quality of larval substrate used has influence on development
time (Table 3). Managing high temperature in tropical countries is easy but difficult in temperate
countries and energy consuming.
Table 3. Survival rate, development time and yield of black soldier fly reared on livestock manure
Substrate
Poultry manure
Pig manure
Cow manure
Survival rate
82.2±13.5a
97.0±4.73b
87.8±5.00a b
Development time (d)
144.0±33.1a
144.0±52.8a
214.5±21.6b
Yield (g fresh wt)
5.68±1.60
6.9±1.40
7.4±1.4
P<0.05
Housefly larvae (maggots) can also be grown on cattle, pig and poultry manure and alleviate
environmental pollution caused by manure accumulation through biodegradation and reduced
pathogenic bacteria. Municipal organic waste is also used as substrate for house fly larvae
production as protein source for poultry (Veldkamp and Bosch, 2015). Agriprotein Technologies,
South Africa is using human excreta and blood collected from slaughterhouses for maggot
production. A single female fly can ovulate 750-1000 eggs per week which will then hatch into
larvae. Larvae undergo three life stages in 72 h period and are harvested just before becoming
pupae, dried, milled and packed (Veldkamp et al., 2012). One kg of eggs turn into 380 kg of larvae in
72 h. Rearing of adult flies for breeding stock was described by Cickova et al. (2012) with fresh pig
manure. For pupae production four different types of pig manure (fresh manure, manure with or
without saw dust and centrifuged slurry) were used. Larval survival rate (%) ranged from 46.9 in
manure without saw dust to 76.8 in centrifuged slurry. About 44-74 g house fly pupae was produced
while wet manure decreased from 1 kg to 0.18-0.65 through biodegradation with marked
differences among manure types used.
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Mealworms (yellow) are also able to convert low nutritive organic waste products into high quality
protein. They have been grown on dried and cooked waste materials from fruits, vegetables and
cereals in various combinations (Ramo Elorduy et al., 2002). Collavo et al. (2005) reported that one
kg of insect biomass is produced from 2 kg of feed biomass. If 1.3 billion tons bio waste available
globally in a year if used for insect farming about 650 million tons insects can be produced which is a
valuable protein source for monogastric livestock and fish besides managing bio waste in an
environmentally and economically viable manner. Assuming 35% DM and 50% protein, the quantity
of quality protein available from the produced insects for feeding pigs, poultry and fish is about 114
million tons. Processing of insects with opportunities and limitations was discussed by Veldcamp et
al. (2012) and EFSA Scientific Committee (2015) in their reports.
Nutritional Composition
Most insect species dry matter content was 40% with the exception of black soldier fly
(26.8%). In processed insects (in dried and ground form) dry matter content was 90% (Veldkamp et
al., 2012). The crude protein content of a insects of different orders ranged from 13 to 77% of dry
matter (Xioming et al., 2010) while the average protein content was reported to range between 7
and 48 g/100 g fresh weight (FAO, 2012). The crude protein content of insects varied considerably
across insect species and within insect species besides at different life stages. Feed of the insects
influences the nutritional composition (Bukkens, 1997; Finke, 2005; Oonincx and Dierenfeld 2012;
Rumpold and Schluter, 2013; Makkar et al., 2014; Micek et al., 2014; Sanchez_Muros et al., 2014).
On DM basis lowest median protein was found for the black soldier fly larvae (42.3%) and prepupae
(38.1%) and highest for common housefly pupae (62.5% of DM) as reviewed by Veldkamp et al.
(2012). Yellow meal worm and house fly larvae were comparable in crude protein content (median
49.3 and 50.8 % of DM). Soybean meal (defatted) which is the main protein source used in pig and
poultry feed has a protein content of 49-56% but oil content is only 3% fat on DM basis.
Insects are also considerable sources of fat. Reported values range between < 5 and > 50% in
edible insects (Xioming et al., 2010; Rumpold and Schluter, 2013; Makkar et al., 2014; Micek et al.,
2014) Crude fat content of yellow mealworm larvae and pupae was 36.1 and 33.8%, respectively
whereas common housefly larvae and pupae had 20.6% and 15.5% crude fat content, respectively
(Veldkamp and Bosch, 2015). Black soldier fly larvae and prepupae median fat content was 27.1 and
28.8%, respectively on DM basis. Information on carbohydrate content in insects is scanty. Crude
fiber content in different edible insects ranged from 0 to 86% on DM basis (Bukkens, 1997; Finke,
2005; Grabowski et al., 2008; Rumpold and Schluter, 2013; Makkar et al., 2014; Sanchez-Muros et
al., 2014). Most carbohydrates in insects are in form of chitin which may decrease insect protein
digestibility (Defoliart, 2002) and is also considered to induce allergic inflammation (Muzzarelli,
2010). Total ash content of yellow mealworm larvae (3.5%) was lower than those for common house
fly (larvae = 11.2%; and pupae = 7.7%) and black soldier fly (larvae = 11.0%; prepupae = 14.7%). The
crude protein, ether extract and ash content of locust meal and silk worm pupae meal were 57.3,
8.5, 6.6 and 63.3, 17.3 and 5.6%, respectively (Makkar et al., 2014). Similarly silk warm pupae meal
contain 60.7% protein, 25.7% fat and 5.8% ash. .
Minerals
The mineral content of 32 species (mainly larvae) was summarized by Finke (2005). Ranges were
given in g/kg DM for major minerals, Ca (0.4-24.8), P (1.2-14.3), Mg (0.3-27.4) and in mg/kg DM for
trace elements, Cu (9-265), Mn (3-39), Zn (21-390), Se (0.3-400). Makkar et al. (2014) summarized
the major mineral and trace element content of black soldier fly (larvae), common house fly (maggot
and pupae), mealworm (larvae), locust, house cricket (adults) and silk warm pupae meal. Most
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insects contained higher levels of phosphorus than calcium. The phosphorus availability from insects
in non-ruminants was almost 100% (Micek et al., 2014). Most insects appeared to be good sources of
the trace elements like iron, zinc, copper manganese and selenium (Barker et al., 1998; Belluco et al.,
2013; Rampold and Schluter, 2013) but not for calcium (Finke, 2013). To be used as feed ingredient
in poultry and pig diets calcium and phosphorus contents and their ratio are important. Black soldier
fly had the highest calcium phosphorus ratio (8.4) with other insects having lower ratios (0.29 to
1.28), see Makkar et al. (2014). Commonly used protein supplements, soybean meal and fish meal
have calcium phosphorus ratios of 0.57 and 1.56, respectively.
Vitamins
To date studies on vitamin content of edible insects are inadequate (Micek et al., 2014). Vitamin
content insects as reported ing from black soldier fly (larvae) and common house fly (adult) by Finke
(2013) were as follows: retinol (<300 μg/kg), vitamin D2 (<2 μg/kg), Vitamin D3 (2.5 μg/kg), αtocopherol (6-30 mg/kg), vitamin C (<10-23 mg/kg), thiamin, B1 (0.1-11 mg/kg), riboflavin, B2 (16-77
mg/kg), niacin B3 (34-91 mg/kg), pantothenic acid B5 (27-45 mg/kg), pyridoxine B6 (1.7-6.1 mg/kg),
folic acid (08-2.7 mg/kg), biotin (0.35-068 mg/kg), vitamin B12 (5-237 μg/kg) and 625-1100 mg/kg
choline. When insects are used as food/feed the vitamins likely to be the most deficient will be
vitamins A, D, E, B1 and B12.
Energy
Gross energy (MJ/kg DM) contents of black soldier fly, housefly maggot, housefly pupae,
meal worm and locust meals were 22.1, 22.9, 24.3, 26.8 and 21.8, respectively. Soybean meal which
represents two thirds of the total world output of protein feedstuffs including all other oil meals and
fish meal (Oil World, 2010) has a gross energy value of 19.7 MJ/kg DM. Digestible and metabolizable
energy values for insects are scarcely available in the literature and there is an urgent need to
generate these information. .
Amino acids
Amino acids concentrations in the protein determine the quality of protein. In comparison to
fish meal and soybean meal, histidine, lysine and tryptophan are most frequent limiting amino acids
in insects (Sanchez-Muros et al., 2014). Veldkamp et al. (2012) summarized in their report that
proteins in black soldier fly, common housefly and mealworm were generally lower in arginine and
cysteine (except mealworm larvae) and higher in methionine and tyrosine compared to soybean
meal. First limiting amino acids were tryptophan and lysine in insect protein (Ramos Elorduy et al.,
1997; Finke, 2005; Bukkens, 2005). In general essential amino acids levels were satisfactory in
insects. In fact, essential amino acids levels in silkworm pupae meal and black soldier fly larvae were
higher than in soybean meal or FAO reference protein (Makkar et al., 2014).
The essential amino acid indices (EAAI) of black soldier fly, common house fly and
mealworm were above 1, indicating that these protein sources l would generally provide more of the
essential amino acids than required for broilers and growing pigs (Veldkamp and Bosch, 2015).
Highest EAAI values were found for black soldier fly and yellow mealworm whereas lowest values
were observed for common housefly pupae which was even lower than the soybean meal value.
Chemical scores were also calculated for insect amino acids to assess their protein quality. The
lowest score which indicates the first limiting amino acids in black soldier fly (larvae and prepupae),
housefly larvae and yellow mealworm larvae were methionine or methionine+cytine in pigs and
broilers (Veldkamp and Bosch, 2015). In addition lowest score in mealworm was also observed for
arginine in broilers. In case of housefly pupae the first limiting amino acids with lowest score
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methionine+cysteine for in pigs and arginine in broilers. Soybean meal, the reference protein also
exhibited the lowest score for methionine+cysteine.
Fatty acids
High variation in fatty acids profile across insect species (Lu et al., 1992; Borroso et al., 2014)
was observed. Womeni et al. (2009) reported fatty acids of several edible insect species consumed in
Cameroon to contain quantities (% of oil content) of palmitic, (8-38%), oleic (9-48%), linoleic (7-46%)
and α-linolenic acid (15-38%). While the nutritional value of α-linolenic acid is well documented as
essential fatty acid (unsaturated), the presence of high level of unsaturated fatty acid leads to rapid
oxidation of insect food products during processing which in turn causes rancidity quickly (FAO,
2013). Summarization of fatty acid data of six insect species (Pereira et al., 2003; Barroso et al.,
2014; Makkar et al., 2014) revealed saturated, monounsaturated, polyunsaturated and omega 3
fatty acid levels of 22.2-67.1, 16.9-52.7, 7.5-32.1 and 0.7-24.7 percent, respectively. Unsaturated
(mono+poly) fatty acid levels were higher and saturated fatty acids were lower in all insect species
except for black soldier fly where saturated fatty acids were higher in the total lipid. Omega fatty
acids were rich in silkworm pupae meal and lowest in black soldier fly larvae. Fatty acid composition
of diet influenced lipid content and composition in black soldier fly. Larvae reared on cow manure
had high saturated (37%) and monounsaturated fatty acids (32%) content but were low in omega-3
fatty acids (0.2%). When the same larvae was reared on 50% cow manure and 50% fish offal the
proportions of saturated, monounsaturated and omega-3 fatty acids were, 54, 12 and 3 percent,
respectively and the total fat level increased to 30% from 21% on DM basis. Therefore designing
substrates (bio waste) with more omega-3 fatty acids is desirable for enriching the final biomass (StHilaire et al., 2007).
Digestibility
Literature on digestibility of selected insect species in pigs and poultry is very scanty (3 papers).
Protein digestibility and utilization were good in mono-gastric livestock. Apparent fecal digestibility
of crude protein was similar (76 vs. 77%) where as crude fat digestibility was higher (83.6 vs. 73%) in
castrated pigs fed black soldier fly larvae meal (33% of corn based diet) in comparison to those fed
soybean meal (25.5% based corn diet (Newton et al., 1977). Hwangbo et al. (2009) reported
apparent fecal digestibility of 98.5 whereas Pretorius (2011) reported 69% for protein in broilers fed
common housefly meal based diets. Dried housefly larvae meal contributed t 30 and 50% to the
respective corn based diets. Pretorius (2011) also reported higher CP digestibility for housefly pupae
meal than larvae meal. Both the studies reported amino acid digestibility of more than 90% but
surprisingly Pretorius (2011) reported much lower protein digestibility (69%), attributing it to the
indigestibility of chitin-N and/or ADF bound N. It was reported that chitin can be digested by
chitinase secreted by gizzard in broiler chickens (Han et al., 2017; 2000) but not by pigs, although it’s
intestinal microbiota was able to produce chitinolytic enzymes (Simunek et al., 2001). Further
research on feeding value whole insects at different life stages as well as processed ones is essential
for formulating insect based diets for livestock.
Functional Properties of Insects
The Chitin chemical structure is similar to that of cellulose (β 1-4 N-acetyl-D-glucosamine).
The Chitin contents of black soldier fly larvae and yellow mealworm larvae were reported to be 5.4
and 2.8%, respectively (Finke, 2013). Non insect chitin or chitin derivatives can enhance immune
response in kelp groupers (Harikrishnan et al., 2012), act as antibiotic/probiotic in rats and
chicken(Khempaka et al., 2011) and had hypolipidaemic properties in broilers (Hossain and Blair,
6
2007). Further, the peptides produced by black soldier and house fly larvae thriving on manure or
organic waste are antimicrobial and these peptides might be functional in in monogastric livestock
(pigs and poultry). Therefore functional properties of insects need to be investigated.
Performance of Livestock
Insect meals can be used feed protein in the same way as more conventional protein sources
(soybean meal, fish meal etc.) but may not be able to replace these protein sources entirely. Reviews
of animal feeding trials with insects were earlier published (Ravindran and Blair, 1993; Veldkamp et
al., 2012; FAO, 2013, Makkar et al., 2014; Sanchez-Muros et al., 2014; Veldkamp and Bosch, 2015)
were mainly based on studies executed in developing countries mostly using organic waste and
livestock manure as substrates for the insects.
Pigs
Black soldier larvae meal was marked out for is protein, lipid and calcium content (Makkar et
al., 2014) and was found to be suitable for inclusion in growing pig diets. Black soldier fly prepupae
meal could successfully replace dried plasma meal (added at 5% in the diet) at 50 percent level with
slightly better performance (+4% gain and +9% feed efficiency) with or without amino acid
supplementation (Newton et al., 2005). Supplementation of some essential amino acids should be
considered since black soldier fly prepupae meal has low chemical score for methionine + cysteine
and threonine but not by 100% replacement of plasma meal (performance -3 to -13%). Probably
further refinement of black soldier fly prepupae meal (rendering and cuticle removal) may be
required to make it more suitable for inclusion in pig diets for better performance. Given a choice,
pigs did not discriminate against a diet containing ground black soldier fly larvae compared with diet
containing soybean meal (Newton et al., 2015). Supplementation of soybean based diet with 10%
maggot meal replacing fish meal (isonitrogenous and isocaloric) did not affect weight gain and feed
efficiency in weaned pigs (Viroje and Malin, 1989).
Poultry
Soybean meal was replaced by black soldier fly and housefly pupae, fish meal by silk worm
pupae meal and fish meal and soybean meal by Chinese grasshoppers in poultry (broiler/layer) diets
(Ravindran and Blair, 1993; Wang et al., 2007). Ramos-Elorduy et al. (2002) could replace soybean
meal up to 10% with dried yellow mealworm meal harvested from low nutritive organic waste
products without any negative effects. House fly maggot meal at 10% and greater level in the diet
decreased performance and intake (Bamgbose, 1999; Makkar et al., 2014) probably due to darker
color of the meal (less appealing to chicken) as well as well as low chemical score for methionine.
Methionine supplementation might improve performance. Teguia et al. (2002), Awoniyi et al. (2003)
and Hwangbo et al. (2009) successfully replaced fish meal in broiler diets with common house fly
larvae (54% CP) on iso-caloric (12.6 MJ) and iso-nitrogenous (20% CP) basis. Feeding diets with 1015% maggot meal improved weight gain and carcass quality of broiler chickens (Hwangbo et al.,
2009) compared to diets with 5 and 20% maggot meal . Replacing 25% of fishmeal in the diet is most
efficient in terms of weekly weight gain and protein efficiency without influencing carcass
characteristics (Awoniyi et al., 2003). Average daily gain, slaughter weight and feed intake increased
in broilers when compared with corn-soy meal based diets when maggot meal was supplemented in
three phase feeding system (Pretorius, 2011).
No significant difference in performance was found between 10% housefly larvae (maggot)
meal and 10% fish meal supplemented broiler chickens. In fact broilers fed either 10% maggot meal
or 10% fish meal diets had heavier carcasses and breast muscle portion than those on corn-soy
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based diet (Pretorius, 2011). When a 25% larvae meal diet was fed it resulted in significantly higher
live weight at slaughter, feed intake (total and cumulative) and average daily gain than a 25% fish
meal diet (Pretorius, 2011). Teguia et al. (2002) similarly concluded that from a technical and
economic point, maggot meal could replace fish meal in broiler diet. In layers maggot meal could
replace 50% of the dietary fish meal (constituting 25% of total dietary protein) without affecting egg
production and shell strength (Agunbiade et al., 2007). Twenty four broiler feeding trials (Africa-17,
Asia-4 and US-3) in which various levels of house fly maggot (larvae) meal were fed and twelve
broiler studies (9 from India) in which silk worm pupae meal was fed were summarized by Makkar et
al. (2014) who reported that insect protein could replace soybean meal, groundnut cake and fish
meal essentially in its entirety . Weight gain, feed intake, feed conversion and slaughter parameters
and meat quality was not affected by replacing fish meal up to 100% in broiler diets with silk
worm/pupae meal (Ijaiya and Eko, 2009; Kumar et al., 1992).
Ruminants
No feeding experiments with insects as dietary protein supplement was reported (Makkar et al.,
2014) since the use of insects in feed for cattle is not currently an issue due to lower interest and
acceptance of milk, dairy products and beef from insect fed cattle among farmers, stakeholders and
consumers. However, a study on silk worm pupae meal (non-defatted) indicated that it could replace
33% groundnut cake safely and economically (on weight basis) in fattening Jersey calf diets (Narang
and Lal, 1985).
Cost economics
Price of feed ingredients for animals are rising faster prices for meat prices and particularly
the price rise of fish meal is remarkable. FAO is expecting that the price for a number of feed
ingredients will increase further till 2019. Though prices depend on insect species, insects price was
more currently than the common protein supplements for feeding monogastrics/aqua. To be
competitive the price of insects in should be around € 0.4 (₹ 80) per kg insect biomass based on a
35% DM content (Veldkamp and Bosch, 2015). Current fish meal price in India is ₹ 85/kg. High grade
protein meal from black soldier fly larvae is sold by Protix Biosystems, The Netherlands at € 20/kg
(2014) for testing purpose on DM basis. Agriprotein, South Africa is selling maggot meal @ 1.08/kg.
Based on the current prices it looks insect protein appears to be most competitive with fish meal
(Table 4) whose price is €1.24/kg (similar to Indian price) and is expected to increase in the near
future. Soybean meal price (480 g protein/kg) is approximately € 0.57 which is also similar to India at
current prices. Increasing the size of insect rearing companies with higher level of mechanization/
automation will decrease the price of insects. Beneficial functional properties if identified for insects
it will add value to the insects and competitive in the market.
Table 4. Prices of various protein supplements in relation to insects (88% DM basis)
Protein source
Mealworm
Soybean meal
Fish meal
Grain**
Protein
content (%)
50
48
65
12
Netherlands
Price
Price (€/kg
(€/kg)
protein)
15.8
31.7
0.57
1.19
1.24
1.91
0.14
1.17
India*
Price
(₹/kg)
?
39.0
85.0
16.1
Price
(₹/kg protein)
?
81.3
130.8
161.0
Meuwissen (2011); Veldkamp and Bosch, (2015)
*Prices are obtained from local market on 15.11.15
**On maize grain CP (10%) and price basis for India.
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Environmental Foot Print of Insects Farming
Insects have a higher relative growth rate and better feed conversion rate while emitting less
greenhouse gases than cattle (Oonincx et al., 2010) and less or comparable levels than pigs (Table 5).
Further, the production of ammonia by insects is also lower than by conventional livestock. This
comparison is valid when insects are used for direct human consumption. However, if insects are
used as feed ingredient a comparison with the foot print of common feed ingredients such as
soybean, rapeseed and fish meals will be more desirable and appropriate.
Table 5. Greenhouse gas (CH4, N2O, CO2 eq.) and ammonia (NH3) emissions per kg of mass gain for
insect species, pigs and beef cattle
Species
Tenebrio molitor
Acheta domesticus
Locusta migratoria
Pigs
Beef cattle
g/kg mass gain
CH4
CO2 eq.*
0.1±0.03
7.6±2.3
0.0
1.6±1.8
0.0
17.7±31.2
1.92-3.98
79.6-1130
114
N/A
N/A = Not available
Oonincx et al. (2010)
mg/kg mass gain
N2O*
NH3*
25.5±7.7
1.0
5.3±6.1
142
59.5±104.8
36.0
106-3457
1140-1920
N/A
N/A
*P<0.05
Risk Profile of insects
The European Food Safety Authority (EFSA) assessed the microbiological (bacteria, virus,
fungi), chemical (hormones, drugs, toxins heavy metals etc.) and environmental risks arising from
the production and consumption of insects as food and feed for food producing animals, fish, pet
and humans relative to such risks as posed by the use of more conventional animal protein sources
in food and feed (EFSA Scientific Committee, 2015). Specific production methods, the substrates
used, the stage of harvest, the insect species as well as methods used for processing will have impact
on the presence of biological/chemical contaminants in insect food and feed products. When
currently allowed feed materials are used as substrate to feed insects, the possible risk of
microbiological hazards is similar to their occurrence in other non-processed sources of protein of
animal origin. The possible occurrence of prions in processed insects will depend on whether the
substrate includes protein of human or ruminant origin.
The environmental risks of insect farming is also comparable to other animal production
systems. Existing water management strategies should also be applicable for managing insect waste
(include insects and insect waste) from insect production. There are no systematically collected data
on animal and human consumption of insects. There are only few studies published on the
occurrence of microbes potentially pathogenic for vertebrates and hazardous chemicals in reared
insects. Further research for better assessment of microbiological and chemical risks from insects as
food and feed including studies on the occurrence of hazards when using particular substrate (food
waste, manure, offals etc.) is required. Risk assessment related to microbiological, chemical, heavy
metals, drugs and hormones, pesticides, allergens and environmental hazards were extensively
discussed by the EFSA Scientific committee (2015) in its report.
Major Concerns
1. More awareness and knowledge required
9
Out of 1300 respondents from 17 countries 88% opined that more information should be available
on the use of insects as food/feed source. 66% expressed that insect larvae are fit for human/animal
consumption as protein source. Some consumers are willing to consume food from animals that
were fed insects as part of the diet but this should be mentioned on the food label. However, about
52% said that will not eat chicken, pork or fish fed diets supplemented with insect protein because
lack of enough awareness which need to addressed.
2. Legislative and regulatory issues
Fat extracted from insects in purified form is allowed in be included in animal diets while whole
insects or insect protein use in animal diets is prohibited since being processed they are considered
processed animal protein sources from farm animals as per EU regulations (Ex. Transmissible
Spongiform Encephalopathy). Attention should also be paid on regulations covering the safe use of
substrates such as vegetable and domestic wastage and manure (animal/humans) on which insects
can be reared most economically.
3. Scaling up
If insects replace 5% in feed for broilers, the quantum of insects required for feeding broiler
population would be 75,000 t in Netherlands. Economically viable unit can produce 365 t
insects/year (1 t/d) which means 200 units such small scale insect units are required in Netherlands.
Hence, for large scale production further scaling up is a must. Similarly if the quantum is calculated
for India, the quantity of insects required to replace 5% feed in poultry (both broilers and layers) will
be 1.1 million tons on 88% DM basis. In such case 3000 small scale insect producing units (capacity
365 t/year) are required in India.
4. Risk assessment
Evaluation of nutrient digestibility and nutritive value of insects (processed) for mono-gastric
livestock and aqua is important from a safety point of view. Potential beneficial functional properties
of insect proteins needs to be identified so as to create an added value to the insect protein. For
developing regulations as extensively discussed by EFSA Scientific committee (2015), risk assessment
of use of insects as feed ingredient is needed. This ensures legal provisions on the use of insects for
food and feed production would serve to control and regulate the use of insects by industry
processors and guarantee consumer access to information.
5. Expensive processing methods
Larvae of insects (black soldier fly, housefly and yellow mealworm) need to be processed for
improving their shelf life and food safety but processing methods (freezing/freeze drying) are very
expensive which needs to be economized by developing suitable processing technology.
6. Animal welfare for insects
Animal welfare rules are also applicable and effective when insects are farmed for food/feed
similarly to that of animal farming. As per animal welfare rules, insects needs to farmed without
pain, injury and diseases and without discomfort. But still there is lack of knowledge on these issues
to what extent these concepts of pain and discomfort apply to insects. .
Future research
To make use of insects as a feed ingredient in the monogastric livestock (pigs and poultry) feed
chain, additional research on substrate needs per unit of insect biomass production in different
10
species is required. Further substrates, feeding value (processed/unprocessed insects, extracted
nutrients) in pigs and poultry with cost economics, functional properties of the insects as feed
ingredient, inclusion levels in poultry and pig diets, safety and sanitary measures when using bio
waste as substrate for rearing insects, extraction of nutrients (protein, fat, minerals, vitamins, chitin
etc.) to add value, shelf life, environmental foot print of insects (life cycle based) in comparison to
common protein feed resources (soybean meal, fish meal, rapeseed meal etc.), and insect waste
management need to be investigated.
Conclusion
To include insects as feed ingredient in the pig and poultry diets on a large scale the scale of
production of insects need to be increased providing continuous quantity and quality. To be
competitive the cost of insect production need to be more economical than currently used protein
supplements. Establishing legal regulatory framework for use of insects/insect meals as animal feed
and improved risk assessment methodologies are also very important for attracting investment in
commercial insect farming. In addition, development of insect value chain by sharing knowledge and
creating awareness among stakeholders of the insect industry (organic side stream suppliers, insect
farming and processing industries, animal feed industry, pig and poultry producers, retailers and
consumers) and also lobbying to accept insects as feed ingredients for monogastric livestock in
different countries helps to grow insect farming quickly on commercial scale which in turn contribute
to global food security.
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