Poultry meat contributes more than 50% of total meat market in India (DAHD, 2019). It becomes important to produce those poultry birds economically and effectively. Insects are supposed to be efficient and high quality sustainable protein source which can contribute to the global feed security.
With the increasing human population, which is expected to reach about 9 billion in the year 2050 (FAOstat, 2019), the demand for animal protein is expected to accelerate in the near future. Also, the cost of production of major protein sources such as soy bean meal and fish meal is very high and the resources used for their production may also get limited in future. Therefore, an alternate source of animal protein is needed to meet this alarmingly increasing demand and insect meal has the potential to meet this demand. The insect meal which is a good source of amino acids and fatty acids may act as a promising protein source for the poultry industry. In addition to that, when the feed cost accounts for 65-70% of the total cost of poultry production, a cost effective animal protein source is the need of time to make the broiler production profitable and sustainable for small scale farmers. Insects too contribute in the circular economy by converting the low-value waste into high quality protein source for broiler production. In this way insects may help to reduce the waste loads of the environment and also produce lower carbon footprints. Thus, it can be concluded that insect can play an important role in production economic and sustainable protein source for poultry.
Use of Insects in broiler feeding
Insects have been a part of poultry diet since ancient time, when they were allowed for free-range feeding system. Chickens used to pick up and the insects voluntarily, which showed that insects are part of their diet. It is a rich source of protein and has been traditionally used in the diet of animals as well as humans. Figure 1 represents the major use of insect meal as protein source in broiler diet. Insect meal which is rich source of protein, essential amino acids and fats is a good alternative for animal protein source and will also contribute towards the environmental waste management.
The nutrient composition of insects vary depending upon the physiology of the insect, sex, species and the type of diet fed to the insect for their growth and development. The insects which are used as a supplement in the broiler diet are Black Soldier Fly (BSF), housefly (HF), mealworm (MW), silkworm pupae (SWP), earthworm (EW), grasshopper (GH), locust, cricket and cirina forda (westwood). The insect can be supplemented in the various forms like; live, chopped, or dried and ground forms. The insect meal can partially replace the protein sources such as fish meal, soy bean etc. in the commercial broiler diet. The protein content of edible insects is generally higher than the plant protein sources (Soy beans, cereals and lentils) which is about 30-60% on dry weight basis. However, on average the range for fat and carbohydrate content is about 15-35% and 10-30% respectively. Female insects have more fat than males and also larvae and pupae contain more fat than adult insect. The fatty acid profile depends on the species and diet of the insect. Edible insects generally have lower saturated fatty acids (SFA) in comparison to unsaturated fatty acids (UFA).The digestibility of insect protein vary greatly due to the presence of hard exoskeleton which contains higher percentage of chitin which is difficult to digest. However, this exoskeleton can be removed during the processing of insects and digestibility can be improved. Research study showed that chitin has a positive effect on immune performance of poultry and could also reduce antibiotics use. The carbohydrate exists in two forms glycogen and chitin inside the insect body and on average the range is 7-20% on dry weight basis. The insects also contain high amount of antimicrobial peptide which is present in plenty in various species.
Effect on broiler production performance
The level of inclusion of different insects in the commercial diet of poultry varies according to the species of the birds. Generally available literature shows that the partial replacement of soy bean meal or fish meal in the diet of broiler chicken has no adverse effect on the growth performance. The growth rate and digestibility of various nutrients have shown similar pattern or even better effect when compared to fish meal or soy bean meal based diet. The inclusion of insects has no adverse effect on average daily gain, feed intake, feed conversion ratio in broilers. The average daily gain (ADG) decreases if the inclusion level of insect is 10% or more of the conventional protein source in the commercial broiler ration. This may be due to the dark color of the meal or an imbalance of the amino acid profile when the inclusion levels are greater than 10%. This is mostly in case when black soldier fly larvae, mealworms, and maggots are supplemented in broiler diet. However, supplementing 10-15% of maggot meal in the diet of broiler chicken will significantly improve the growth performance and carcass characteristics while replacement of 25% of fish meal with maggot meal in the broiler’s diet will improve the average weekly weight gain and protein efficiency ratio. The supplementation of mealworms in soy bean meal based diet have no any adverse effect on the body weight gain(BWG), feed intake(FI) and feed conversion ratio(FCR). However, by the substitution of soybean meal with BSF larvae meal similar weight gain is noticed as compared to control group but the feed intake get reduced which shows a better FCR in case of BSF larvae meal.
Sustainable rearing/production of insects
The production of the edible insects generally requires less land area and water and also the emission of greenhouse gases are very few as compared to other protein sources. That’s why they produce lower carbon footprints in the environment. These insects are cold blooded can be efficiently reared on organic waste including pig and poultry manure. Also, insects take shorter interval of time to reproduce and have fast growth rate as compared to plant and animal protein sources. Insects can give many more cycles of production per year in comparison with other protein sources. There are various types of insects available abundantly in nature and can be utilized by the poultry for feeding purpose. The nutritional value of these insects depends on the type of the substrate they are reared upon. Insect Black soldier fly (BSF) can be reared on immense varieties of organic waste such as manure, food waste, rice straw, fecal sludge, kitchen waste and animal offal etc. BSF harvest them by themselves (self-harvesting) i.e., they leave their substrate at pre-pupae stage and move to a clean place themselves which makes their farming less labor intensive. The feed conversion ratio (FCR) of BSF is also better as compared to mealworms and crickets. Insects convert low-value organic waste (industrial and agricultural) which cannot be directly consumed by poultry into high value products creating circular economy loop. Therefore, the insects can be used for the purpose of environmental pollution reduction and waste management along with providing protein source for feeding the poultry.
Insects have been used in India for various purposes such as food, medicine, fertilizer and silk. On average about 255 insect species are being used as food and silkworm pupae are consumed as a delicacy in northeast India. The unacceptability of insect fed poultry meat by some people may be due to their cultural difference or religious taboos. The disliking of insect fed meat by the existing culture cannot be changed overnight. Continuous promotional efforts and awareness regarding the nutritional value, sustainability and cost effectiveness of edible insects among the consumers is needed. The processing technology should focus on retaining or improving the nutritive value, texture and taste (palatability) of the insect fed broiler meat.
Existing literatures confirms that insects are a good source of protein (amino acids), fats and has the potential to substitute soy bean meal and fish meal in the diet of broilers. The amino acids lysine, histidine and tryptophan are most frequently present in insect meal depending upon the species of the insects. Also, the cost of production of soy bean and fish meal is very high and insect may prove to be an alternate protein source at lower cost of production. Production of edible insects is now evolving and gaining importance as a sustainable protein source for broiler production globally to meet the increasing demand for animal protein in the feed industry. The insect also contributes to reduce the environmental pollution and produces lower carbon footprints. Thus, the edible insect proves to be a profitable and sustainable source of protein. The mass production of insects is needed to make it cost effective and to be utilized by the farmers in the broiler’s diet. Further additional research needs to be done in the near future in the area of level of inclusion of various insects, their feeding value, and functional properties of the feed ingredients. Thus, insect has can be a promising protein source for broiler production and its utilization in broiler’s diet is technically feasible. Also, creating awareness among the consumers regarding safety and nutritional value of insects is important.