Insects represent a sustainable, attractive, and safe ingredient alternative to satisfy the world’s growing demands for food. This is especially true for animal nutrition.
This nutritional strategy is truly attractive for the animal feed industry, considering the fact that when compared to other commonly used ingredients such as meals of animal origin and soybean meal, this alternative provides significant amounts of proteins, lipids, minerals, as well as other nutrients.
Insects can be fed with agricultural residues and organic waste which represents a major advantage in regards to reducing environmental impacts and waste mitigation. Which reinforces the use of this alternative ingredient in animal feed.
In addition, they reduce production costs and intervene in the development of beneficial microbiota. As well as reducing the competition for food resources, and acting as immunomodulators.
Currently, some studies highlight the nutritional strategy of using different insect meals as supplements of conventional protein sources, or as total replacements for these. As they represent an ingredient which offers significant results from a zootechnical standpoint, generating positive impacts in productive systems. Hence, researchers believe that insects deserve special attention when it comes to animal nutrition.
Use of insects in poultry nutrition
The nutritional requirements of monogastric animals include higher quality and quantity of protein in the diet from a nutritional point of view. Therefore, protein sources must have a high content of this nutrient, an adequate amino acid profile, high digestibility, and good palatability without antinutritional factors (Animal Feed Resource Information System [AFRIS], 2015).
What has promoted the search for new nutritional alternatives?
The search for alternative and sustainable proteins is essential and needs short-term solutions, making insects an increasingly attractive feeding option for birds. The natural behavior of wild and domestic birds is the consumption of insects, especially in the early stages of life (Makinde, 2015).
The high nutritional requirements of broilers, laying hens, and other bird species and the low-profit margin obtained by the producer are factors that promote the search for ingredients with high nutritional value. As one of these alternatives, some studies in the poultry area show that the common housefly (Musca domestica) larvae are a widely used alternative as feed for broilers. A feed option that positively impacted countries such as Nigeria, Russia, South Korea, India, China, and Cameroon, among others (Hwangbo et al., 2009).
Larvae in broiler feed
Housefly larvae are used to feed broilers, both in fresh and dried form. It is considered that in the dry state, there are some advantages, e.g., facilitates transportation, increases the storage time of this ingredient, and can replace other traditional ingredients in diets, such as fishmeal, soybean meal, meat, bone meal, among others, allowing good productive performance to be maintained in broilers. In South Korea, insect larvae are of great importance. It has been shown that chickens fed this ingredient improves meat quality characteristics and increase live weight by 10 to 15% (Hwangbo et al., 2009).
Experience in the use of insects in India
In India, conventional feed accounts for about 60% of the total cost of poultry farming, but the scarcity of feed sources such as corn and soybeans makes feed production difficult. This trend or behavior is only increasing (Medhi, 2011). Therefore, collecting some insects that act as agricultural pests becomes a source used as ingredients in animal nutrition, thus reducing the incorporation of harmful pesticides by humans, generating a positive impact on the environment, and using this source of nutrients as an alternative animal feed.
By using some insects as alternatives in animal nutrition, several researchers have focused on studying the nutritional composition of most species of those insects used in diets, including four species of acridids: common locusts (Oxya fuscovittata), common locusts of India (Acrida exaltata), rice locusts (Hieroglyphus banian) and short-horned grasshoppers (Spathosternum prasiniferum prasiniferum) (Anand et al., 2008; Al-Qazzaz & Ismail, 2015).
Most studies show that insects are a viable alternative characterized by having a higher protein and fat content than traditional sources such as soybean meal and fish. Therefore, it is an option that can be implemented in food production for animal nutrition (Anand et al., 2008).
Insect protein quality
Insects are generally little used in commercial food production, but some studies estimate that the quality of the insect protein has potential as a food ingredient. In addition, many pet birds are considered phytophagous and entomophagous. In practice, there are generally no birds that feed only on plant materials since most of these birds need protein, which is why they are considered entomophagous. Therefore, the consumption and production of insects are very beneficial (Vidotto -Magnoni & Carvalho, 2009).
Relevance gained by insects in poultry nutrition
To show the importance that insects have achieved in poultry nutrition, some studies and their results are presented: Aigbodion et al. (2012) experimented with broiler chickens where American cockroaches (Periplaneta americana L.) were used in the diets to evaluate the growth of chickens at eight weeks of age. Therefore, the researchers observed that chickens fed the diets that included the insect meal presented the best results in terms of performance compared to the control treatment, which was a basal diet with conventional ingredients.
Effects of inclusion of corn weevil larvae in broiler diets
Studies by López-Verge et al. (2013) aimed to find the effects of including corn weevil (Sitophilus zeamais Motschulsky) larvae in the diet of broilers. As a result, they observed that the chickens fed with the diet that contained insect larvae had a higher final body weight, higher feed intake, and better feed conversion compared to the group of chickens that received a diet based on soybean meal or control diet, the observed results were justified due to a higher proportion of protein present in the larvae.
Meal-supplemented diets with Black Soldier Flies
When working with a diet based on corn and soybean meal as basal feed (control), and diets supplemented with 5%, 10%, 15%, and 20% meal of the soldier fly (Hermetia illucens) Dabbou et al. (2018), observed that diets containing between 10% and 15% insect meal improved carcass quality, live weight and higher feed intake, these results were justified by the authors due to the excellent palatability of the food, Regarding the blood parameters, there was no significant difference, therefore, chickens that received the diet with the inclusion of 15% of the insect meal presented lower height of the intestinal villi, greater depth of the crypt and lower height-depth ratio of villi compared to the other groups.
Inclusion of insect meals in the feed: Chicken meat quality
Altman et al. (2018) observed that the inclusion of insect meals in the feed could influence the quality of chicken meat. Chickens that received diets with insect meal presented more stable pH levels in fresh breast fillet for up to seven days after packing, in comparison with the breast fillet of the group of chickens that received a control diet (without meals)
Effect of high-fat insect supplementation
A study by Vencería et al. (2020) investigated the effect of supplementation of high-fat insects (Tenebrio molitor and Zophobas morio) in balanced diets to evaluate the performance, growth, and immune system of broilers. Six treatments were evaluated in this study, a negative control diet, a positive control diet with antibiotic addition, and four diets containing 0.2 and 0.3% of T. militar and Z. morio. They observed that small amounts of insect supplementation improved daily weight gain and feed intake and altered specific immune system characteristics, such as the production of immunoglobulins and interleukins in broilers.
Laying hens fed with insects
Regarding laying hens, there is little information. Still, a study carried out by Ying Chang et al. (1996) showed that the substitution of 5% of the fishmeal by larva (T. militar) meal resulted in a 2.4% increase in the laying rate of the hens. They justified that this result is due to a more significant amount of protein and some minerals, such as calcium, from the insect meal.
Mwaniki et al. (2018) evaluated the inclusion of 7.5% meal of the black soldier fly (Hermetia illucens) in the feed of laying hens and observed that the production and the average weight of the eggs were similar to the results observed with the control diet. (without insect meal). But the quality of the eggshell was measured through the resistance to cracking, and the thickness increased considerably with the inclusion of the meal. The authors justified the results due to greater absorption of calcium in the intestine of the hens.
Inclusion of Black Soldier Fly meal in laying quails
Another study developed by Zotte et al. (2019) evaluated the inclusion of meals from the soldier fly (Hermetia illucens) in diets of laying quails, for which they did not observe a significant difference in the performance of the birds, while the birds that received diets with a meal of the insect presented higher percentage of shell, greater pigmentation of the yolk and greater oxidative stability of the product, achieving a longer storage time.
Conclusions
The use of insects in animal feed as a protein ingredient is a subject that has been little researched and is not well known in the feed industry. However, due to the few investigations carried out on this topic in underdeveloped countries, they present insects as a new sustainable alternative to animal nutrition and friendly to natural resources. These researches have drawn the international community’s attention to investing more and more in the subject. Through these works, it has been possible to demonstrate the nutritional potential of insects.
Therefore, with the development of large-scale insect-rearing systems, the current economic crisis, and rising feed prices, these studies offer an interesting perspective on the use of insects for different purposes, especially in animal nutrition, agriculture, obtaining essential oils, biodiesel production, and contributing to the balance of the environment.
Based on this, it is verified that in the coming years, there will be a significant increase in scientific production related to the use of insects in animal feed as a competitive and superior source compared to traditional protein sources. Furthermore, Central and South American countries have high expectations for the production of insect meals due to the climate and the variety of insects that its fauna possesses. For example, Brazil, a country highlighted as the 5th largest producer of silk in the world, for which it already has larval residues that can be processed or destined directly for animal feed.
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Source: Adaptation of the article “Use of insects as an alternative in poultry nutrition: Review” DOI:10.33448/rsd-v10i3.13274
Authors:
-Fanny Leonila Velasquez Moreno ORCID: https://orcid.org/0000-0001-6791-8455 Federal University of Mato Grosso, Brazil
-Ana Paula Silva Ton ORCID: https://orcid.org/0000-0002-5826-1874 Federal University of Mato Grosso, Brazil
-Cecilia María Guerra Rosa ORCID: https://orcid.org/0000-0001-6842-3200 Tropical Agricultural Research and Higher Education Center, Costa Rica
-Leonardo Willian de Freitas ORCID: https://orcid.org/0000-0002-5796-0403 Federal University of Mato Grosso, Brazil.