Exploring an Alternative Source of Protein for Poultry
Nibedita Nayak
Scientist, ICAR-Central Coastal Agricultural Research Institute, Goa
Introduction
The image of an insect to be our saviour sounds quite frenzy, but food futurists expect them to be so. The whereabouts of this saviour reveals them as capsule of alternate protein capable of meeting protein hunger of billions of people. On considering the ever increase in global human population growing @1.1% per year, food security will be a concern for all incoming times. The UN, which already warns that animal rich diets cannot stretch that far long-term is encouraging govts and businesses to turn to insects to fulfil the planet’s protein needs. Hence to meet the nutritional security, the use of insects as alternate source of cheap, reliable protein is gaining momentum. Besides this the remarkable ability of the insect to convert nearly a wide variety of organic waste into high quality protein while taking all carbon with them and leaving a smaller carbon footprint is a plus. As rightly said by Jeff Tomberlin, they can “Save lives, protect the environment, create jobs and stabilise economies”.
Knowing our Saviour:
The insect that is going to save us from the fear of global food insecurity and currently known to the world belongs to the order of Dipterans, family of Stratiomyidae. It is native to tropical, subtropical and temperate regions of the American continent and widely distributed throughout the world in the name of black soldier fly larvae (Hermatia illucens). The adults are medium sized flies about 7/8 inches long (Hawkinson, 2005), black in colour with metallic reflections ranging from blue to green on the thorax and sometimes with a reddish end of the abdomen. The unique sexual dimorphism describes smaller males than females. The adult female lays between 320-1000 eggs in crevices of rearing unit or adjacent to decaying matter such as waste or compost. Eggs are laid into tight rows close to a potential food source. The eggs are creamy white in colour and hatch within 4 days. The larvae are pale whitish in colour. Larvae pass through 6 instars and require approximately 14 days to complete development. The duration of the larval stage varies from 4 weeks to 5 months, depending on food availability. BSFL are at the pre-pupa stage, they will instinctively leave the substrate and move to a high, clean place, a behaviour called “self-harvesting”. Pre-pupal stage lasts around 7 days. The pupal stage lasts from 1 to 2 weeks. Approximately it completes its life cycle around 45 days. BSF adults cannot feed as they lack mouth parts hence neither act as vector nor transmit any disease.
Raising the food fountain
Black soldier fly larvae can successfully rear on kitchen waste, fish offal, vertebrate remains, municipal waste, human waste and livestock manure. It consumes a wide range of waste materials there by lowering greenhouse gas emissions and reducing environmental impact. They are a boon for ecosystem as they need less water and space even in case of large-scale larvae production. Hence it can be an asset for waste management as well as food security mostly for developing countries without any extra expenditure to solve these burning problems.
Optimal environmental conditions and food sources for larvae
- Warm climate: the ideal temperature is between 24 and 30°C. If too hot, the larvae will crawl away from the food in search of a cooler location. If too cold, the larvae will slow down their metabolism, eat less and develop slower
- Shaded environment: larvae avoid light and will always search for a shaded environment, away from sunlight. If their food source is exposed to light, they will move deeper into the layer of food to escape the light.
- Water content of the food: the food source has to be quite moist with a water content between 60% and 90% so that the larvae can ingest the substance
- Particle size of the food: as the larvae have no chewing mouthparts, access to nutrients is easier if the substrate comes in small pieces
Sustainability of these edible insects:
The potential of the larvae to be used as animal feed is immense as it’s already been considered an alternative to fish meal and fish oil. It is also been accepted as human food in some countries with history of entomophagy. There are some regulations in using this as human food with focus on the substrate in which the larvae being reared. But the potential of the larvae as source of food for animals and human is considerable on considering the looming food crisis.
Nutritional significance of the larvae:
The content of larvae varies with the composition of substrate on which the larvae were reared. For example, BSF larvae farmed on cattle manure contain 21.5% lipid (on DM basis) including lauric acid, palmitic acid, oleic acid and omega-3 fatty acids (Makker et al., 2014). Black soldier fly larvae (BSFL) on an average contains 40.8±3.8% protein and 28.6±8.6% fat. This establishes BSFL as a possible alternate protein source in the face of food insecurity and climate change scenario. They accumulate lipids in their body if fed on fat rich substrate and more palatable to poultry and fish. It has already been used as a partial replacement of maize or soy-based diets for monogastric farm animals. The poultry birds are so fond of BSFL especially laying hens that they search for the larvae in feeders rather than continue to eat commercial ration. It can be included in poultry feed formulation with satisfactory productive performance, meat quality with added benefit of waste recycling. BSFL has the capability to produce protein rich biomass from potentially protein poor organic wastes. It has already been considered to be an animal grade alternative to fish meal because its feasibility and low cost of production. The % of protein in BSFL is in comparison with other insects and plants but the crude fat content is higher than soya and fish. Thus, BSFL is a promising substitution for livestock feed providing added protein and fat besides utilising the manure of livestock. Hence inclusion of this in right proportion will reduce feed cost, provide additional protein to animals and there by improve the production and productivity.
Input and output of BSFL rearing system (Jeff Tomberlin)
Organic waste (2000 pounds) – Soldier fly larvae (1.6 million)- Protein (100 pounds) and compost (400 pounds). In one year, a single acre of soldier fly larvae can produce more protein than 3000 acres of cattle and 130 acres of soyabean. Thus, making it a source of cheap yet high quality protein with less water and space utilization than its conventional protein counter parts. Hence home rearing of this edible insects is in practice in Asia either to compost the waste or use it as animal feed. Industrial rearing of this soldier larvae is a successful enterprise in China. Processing of this larvae in different ways is a promising option to be used as human food if legally accepted in different countries.
Conclusion
This “mini-livestock’ bears immense potential to be a promising tool in the adverse face of climate change, escalating population growth and global food security. The holistic method of raising this food fountain is suitable for both developing and developed countries.
