What it takes to rear insects for use as animal feeds

Wednesday March 18 2020
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Dr Chrysantus Mbi Tanga, a leading research scientist at Icipe explains a point on rearing insects. According to researchers, there are many benefits in rearing insects. FILE PHOTO | NMG


High price of feeds remains the biggest burden to many livestock farmers, with the input accounting for up to 60 per cent of the total production costs.

Farmers can, however, bring down the costs by rearing insects like crickets and black soldier flies on the farm to use as feeds.

Dr Sevgan Subramanian, a principal scientist at the International Centre of Insect Physiology and Ecology (Icipe), notes that crickets, black soldier flies and locusts can be used to make nutritious feeds for fish, poultry and pigs.

For crickets, scientists have identified the species Scapsipedus icipe, which is edible and can also be mass-produced for human consumption as a quality protein ingredient in animal feeds.

The insect is commonly found around buildings and in fields and bears a yellow band between the eyes, differentiating it from other species.

Crickets have 62.3 to 67 per cent protein, which is equivalent to the percentage in fish, whose protein levels are about 66 per cent and ahead of chicken, which has 30 per cent.

They are also rich in fatty acids, calcium, iron and vitamin B12, according to Dr Subramanian, whose organisation has partnered with the International Development Research Centre (IDRC) to train farmers on producing the insects.

The expert notes that 10 crickets collected from behind the yard or on the farm can make a colony in few months.

“This is a low-cost technology with low investment and short development time. Crickets produce thousands of eggs.

Therefore, a farmer keeping them for sale can make good cash,” Dr Subramanian says, adding the insects require minimal labour and supervision.

To start keeping them, one needs a plastic box with a lid (the size of a ballot box), used grains commonly known as machicha, cotton balls and egg trays made of paper.

The egg trays are arranged inside the plastic box and moist cotton balls, whose sizes are smaller than a fist, are placed in random places inside.

Once the houses are ready, a farmer then captures the insects and keeps them in the box in a warm room. “The number captured determines the size of the second and subsequent generations, and ultimately the pace at which the business will grow,” he says.


The crickets feed on the used grains inside the box and more should be added when they are depleted. According to the scientist, insufficient feeds may see the crickets to cannibalise each other to meet their protein demand.

The used (spent) grains, which can be from sorghum, are high in protein and carbohydrates. It is also recommended that high quality feeds and a balanced diet be given to the insects, especially if they are being kept for human consumption.

“As the natural mating process starts, the female crickets will lay eggs inside the cotton balls, which provide a conducive ground to save them from drying up. This ensures 90 per cent hatchability,” Dr Subramanian explains.

Moist cotton balls also help provide drinking water for the insects, including the males, which are known to eat eggs. The females, therefore, learn to push their eggs inside the cotton balls for safety.

After five days, fresh cotton balls should be put into the boxes and the old ones with eggs transferred to another container and left to hatch.

“The advantage with crickets is that generations can be created by just providing them with food and water. Crickets can breed quickly, often multiplying within 10 days,” says Dr Subramanian, adding that it takes 34 days for the insects to mature.

But for this to happen, they should be kept in temperatures not exceeding 33 degrees centigrade. In circumstances where temperatures drop to below 20 degrees centigrade, the maturity period can extend to over 120 days.

“African farmers are lucky because they have natural temperatures of between 25 and 30 degrees centigrade, which allow the crickets to mature within 48 days. They, therefore, do not have to warm the room as that would be an extra cost,” says Dr Subramanian.

From a single box with 5,000 eggs, a farmer gets three to four kilos of mature insects during harvesting.

It is estimated that 1,000 insects make a kilo. Hence, the more containers a farmer has, the more the kilos to be fetched.

Although crickets can survive for up to four months, the egg-laying stage is usually in the first month. It is therefore not economical to continue feeding them when they are no longer creating another generation, notes the scientist.

The harvested crickets are completely dried and ground into powder using a machine. The powder is then used as a source of protein when making animal feeds. It can also be used to make biscuits or added to baby porridge.

More than 600 farmers allied to Ndori Cricket Farmers Association in Bondo are currently rearing crickets both for food and as an ingredient for animal feeds.


To rear black soldier flies, known as Hermetia illucens, one uses a low-cost technology involving a carton box and a pile of kitchen waste or spent grain.

A section of the carton is cut to make crevices, which flies like laying eggs in. It is then placed in a container of waste, say in a sheltered yard or under a tree.

The waste will attract black soldier flies to feed on as natural mating processes occur. The female flies will lay their eggs within five days in the crevices.

A farmer then waits for four days; within which the eggs hatch into larvae.

The waste provides food that can sustain the larvae (maggots) up to the harvest time, which is between 12 to 21 days.

Dr Chrysantus Mbi Tanga, a leading research scientist at Icipe, says the technology has been tried for three years and found successful.

“After 21 days, the content is sieved. The waste goes down, leaving the larvae atop the mesh. The harvesting should be done before they begin to blacken in transition to the pupae stage. Protein levels are lower once they blacken because they would have used some to develop a harder skin,” says Dr Tanga.

The choice of the fly is informed by the fact that it has more generations in a year. Each fly lays between 500 and 900 eggs at a go.

Cow dung, human waste, rabbit, goat and chicken manure can be used in the place of kitchen waste and spent grains.

“However, tests done show that protein content is higher if the flies are reared on spent grain. It is also easy and more hygienic to handle spent grain than the rest.”

After harvest, the maggots are dried under the sun for at least two days before being ground into powder, which is used in making animal feeds.

Dr Tanga says the flour is high in protein and fats and should be mixed with maize germ or whole maize and others to get fully balanced diet feeds for livestock. The final products are either in the form of powder, cake or pellets.

“Protein content in animal feeds accounts for between 60 and 70 per cent of the total cost. If a farmer can get this cheaply from insects, it means the cost of production reduces by more than half,” says Dr Tanga.

The insect-produced feeds are also high in nutrient value because insects have over 60 per cent of proteins and fat content as compared to conventional feeds in the market, which only have about 10 per cent of proteins, he adds.

According to the researchers, there are many benefits of rearing insects.

One is that whereas 2.2kg of feeds will yield just a kilo of insect protein, a cow would need up to 25 kilos of feeds to produce a kilo of protein.

One litre of water yields a kilo of protein for insects while a cow needs 1,500 litres to produce the same amount of protein, says Dr Tanga.

Also, the amount of greenhouse gases produced by insects is three times less than what is produced by livestock through belching and flatulence.

Health-wise, insects are genetically distant from human beings hence cannot easily pass on diseases to humans the way livestock do, he offers.


Dr Jemimah Njuki, a senior programme specialist at the International Development Research Centre (IDRC), notes that Kenya’s population is projected to hit 96 million by 2050. At that point, animal products will not meet demand for meat and their cost is expected to soar to unaffordable levels.

The cost of beef will increase by 173 per cent, poultry (174 per cent), eggs (503 per cent) and milk 75 per cent.

Dr Njuki notes, therefore, that there is need to mass-produce culturally edible insects like crickets and locusts (nzenene), both of which she declares as highly viable alternative protein that can bridge the demand-supply gap and ensure food security in the wake of population explosion.

The insects can also be used not only as cheap and sustainable feeds, but also as highly nutritious animal feeds compared to fish-based and soya commercial ones.

She says there is hope in law, thanks to a policy framework encouraging the use of insects.


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Eating insects is African culture

According to Prof Monica Ayieko, a specialist in consumer economics at the Department of Food Security, Jaramogi Odinga Oginga University of Science and Technology, insects can play a significant role in food security as they provide alternative protein for human consumption.

Eating insects is part of the solution to malnutrition and food insecurity in sub-Saharan Africa, she says.

Nearly every community in Africa can associate with insect-eating but this is no longer actively happening. Some of these edible insects include termites, grasshoppers, palm weevils or crickets, notes Prof Ayieko.