Insect meal: An alternative feed resources for poultry

Insects are natural foods for poultry. Chickens can be found picking worms and larvae from the grass, soil and litter where they walk. The use of insects in poultry feed is a potential solution to improve the sustainability of poultry diets. Black soldier fly, meal worm, housefly, cricket/ grasshopper/ locust, silkworm and earthworm are the commonly used insect meals in broiler and laying hen diet.

In poultry production, feed cost is approximately 60-80 % of the total cost. Shortage of protein feed resources is the major challenge to the poultry industry. A possible solution to reduce poultry feed cost is finding available, efficient and inexpensive alternative feed sources. Insects are natural foods for poultry. Chickens can be found picking worms and larvae from the grass, soil and litter where they walk. The use of insects in poultry feed is a potential solution to improve the sustainability of poultry diets. Insect meal contains a greater amount of essential amino acids compared to conventional feed stuffs (Al-Qazzaz and Ismail, 2016). Black soldier fly, meal worm, housefly, cricket/ grasshopper/ locust, silkworm and earthworm are the commonly used insect meals in broiler and laying hen diet. The insects can be used as live, dried and paste form for poultry diets (Elahi et al., 2020). A dried insect is considered suitable for poultry diet because the water content in fresh or live insect stimulates the degradation, antimicrobial activity, and Millard reaction (Kroncke et al., 2019).

In recent time, insect meal as a source of protein in poultry diets is gaining attention, which has the potential to lower the feed costs and boost profitability via the utilization of fresh insects for small poultry production.
Insect feed is useful for poultry because:
• Traditional crops such as soy or corn for protein source are very costly
• Chickens love insects
• They improve overall health
• They promote natural behavior
• Insect feed increases productivity in poultry
• Insect feed have prebiotic effect
• Insect feed is more sustainable

NUTRIENT COMPOSITIONS
Insects constitute a high quantity protein source, being rich in essential amino acids and lipids. The protein contents of insect meal can significantly vary, ranging from almost 40-60% (El -Sabrout et al., 2023). The majority of edible insect species exhibit adequate levels of essential amino acids, including tyrosine, tryptophan, phenylalanine, lysine and threonine (WHO, 2007). Insets primarily store carbohydrate in two forms: chitin and glycogen (Triunfo et al., 2021). Edible insects contain varying amount of carbohydrates (mealworms: 14-18%, crickets: 10-20%, grasshoppers: 11-21%, silkworm pupae: 10-20% ants: 2-15% (Weru et al., 2021). Insect have been found to contain a variable content ranging from 2-62% with high amount of unsaturated fatty acids constituting up to total fatty acid content. The vitamin content of insects is not particularly high. They do contain notable amount of vitamins A, C, D and E (Williams et al., 2016). Insects such as crickets and termites have varying mineral contents, with some being high in Mg, Zn and Cu while others such as grasshoppers and mealworms have higher levels of Cu, Mg, Mn and Zn. However, insects are usually low in sodium, calcium and potassium (Mwangi et al., 2018).

DIGESTIBILITY OF INSECT-BASED FEEDS IN POULTRY DIETS
Limited data are available regarding the digestibility of such nutrients in selected for livestock production. According to De Macro et al (2015), insect meals are an excellent source of apparent metabolizable energy and a useful source of digestible amino acids for broilers. According to Gasco et al (2019) the digestibility of insect-based meals for animal feed is influenced by multiple factors, including the insect species inclusion levels and processing techniques. Insect meal possesses the potential to serve as a valuable alternative ingredient in the formulation of animal feeds.

EFFECT OF FEEDING INSECT MEAL IN POULTRY
Due to its nutritional composition, insect male improves growth performance and the exoskeleton of insects mainly consists of chitin, which improves the immune system of chicken. Chitin and chitin derivatives can stimulate the innate immune cells (Lee et al., 2008). Chitin contains about 5% nitrogen (Chu et al., 2020). Broiler chickens fed the containing mealworm meal have better disease resistance and immune response due to prebiotic effect of chitin (Bovera et al., 2015). Chitin in diets also halts the growth of Escolar, salmonella in broiler chickens (Menconi et al., 2014). Hypolipidaemic and hypocholestrolaemic properties of chitin produce leaner meat by decreasing body fat in broiler chicken (Gasco et al., 2018). Feeding grasshoppers to the chickens improved the shelf life of the meat (Sun et al., 2013).

Benefits of incorporating insect meal into poultry nutrition:
• Insect meal in poultry diets could lead to enhanced developmental performance and feed conversion efficiency.
• Utilization of insect meal in poultry diets results in reduced environmental impact in comparison to conventional protein sources (Huis et al., 2022)
• Fish and poultry can derive protein from insects, which serve as a natural source of this essential nutrient.
• It is cost-effective
• Insect-based diets have been introduced to the market to improve feed quality and digestibility.

Limitations:
• The production volumes of fish meal, high -quality soybean meal extracts and soybean meals are hundreds or thousands times greater than of those insect protein sources
• Insect meal might not be as sustainable as other protein sources at the moment
• One of the other key barriers for incorporating insects in animal feed is the lower no. of reared insect species
• For large scale insect production automated process method of raising, harvestings and post harvestings operations are required
• Existence of specific antinutritional compounds, such as protease inhibitors, phytic acids, oxalate, tannins, lectins, and certain insect species limit their use in animal feed and poultry feed
• Inclusion level of insect meal lie between in the range of 2-5% or below

CONCLUSION
Insect meals exhibit great potential as alternative protein source in poultry nutrition due to its nutritional value and cost-effectiveness. Nevertheless, the utilization of insect-based products is accompanied by challenges and limitations. Future research and development could help overcome these challenges and increase the adoption of insect meal as a protein source in poultry feed.

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