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Nutrition
Mineral composition in black soldier fly larvae a promising alternative to fishmeal and soybean meal in livestock feed
Ishaya Usman Gadzama1, Jeannine Malcolm2 and Chris Malcolm2
1School of Agriculture and Food Sustainability, University of Queensland, QLD 4343, Australia
2Mobius Farms, Nuriootpa, Barossa Valley, South Australia 5355, Australia
Corresponding author: Ishaya Gadzama. Email: i.gadzama@uq.edu.au
Introduction: Minerals are essential for various biological functions, such as bone and eggshell formation, enzyme activity, hormone
synthesis, and immune response. Calcium (Ca) and phosphorus (P) are the most abundant macrominerals in the body and have a close
relationship in their metabolism and regulation. Animal feed is often deficient or imbalanced in these two minerals, which can lead to
reduced growth, reproductive efficiency, and product quality. Therefore, it is important to provide adequate and balanced amounts of Ca
and P in animal diets to optimize their health and productivity. Numerous studies have suggested that insects are a rich source of protein
and fats (Veldkamp et al. 2012), however, little information exists on the influence of different drying methods on the mineral composition
of black soldier fly (BSF; Hermetia illucens L.) larvae. The present study evaluated the effect of four drying methods: 1) freeze-drying, 2)
low-temperature air-drying, 3) high-temperature oven-drying, and 4) microwave-drying on the proximate mineral composition of BSF
larvae.
Material and methods: Twenty grams (20 g) of organically raised BSF eggs were incubated at 26 °C and 60% relative humidity and fed
with a standard nursery feed until they hatched into neonates. The neonate larvae were fed a standard feed substrate from day 10 until they
reached the grow-out stage. The substrate was a mixture of pre-consumer food wastes from catering and restaurant businesses, farm-gate
wastes of vegetables and fruits, and a small amount of chicken starter mash. On day 20, the larvae were separated from the frass using a
mechanical sieve and weighed (42 kg). The BSF larvae were euthanised by blanching in water at 9 °C for 40 seconds, followed by cooling
in water at 15 °C. The blanched-and-cooled larvae were air-dried and stored at -20 °C in sealed plastic bags. Four different drying methods
were carried out in batches. Firstly, 10 kg of the frozen BSF larvae were freeze-dried for 72 hours in a commercial facility. Secondly, 2 kg
of larvae were oven-dried at 55 °C for 18 hours (low-temperature dried). Thirdly, 750 g of larvae were oven-dried at 170 °C for 25 minutes
(high-temperature dried). Lastly, 1 kg of larvae were dried in a commercial microwave oven for 20 minutes (microwave dried). The
proximate mineral composition of the differently dried BSF larvae was evaluated following methods of the Association of Official
Analytical Chemists (2002).
Results: The results indicate that the drying methods have some effects on the macromineral and micromineral content of the larvae (Table
1). The most abundant macrominerals were calcium, phosphorus, potassium and sodium as reported by Chia et al. (2020). The high Ca
content may be attributed to the dominance of this mineral in the chitinous exoskeleton of the larvae (Romano et al., 2023) which could
enhance egg production and eggshell quality of chicken layers, as suggested by Park et al. (2017). The Ca/P ratio is also affected by the
drying methods, with the freeze-dried larvae having the highest ratio (3.24 g/kg dry matter) and the high-temperature-dried larvae having
the lowest ratio (2.66 g/kg dry matter). This may have implications for the nutritional quality of the larvae. The micromineral content such
as copper, iron, manganese and zinc were relatively similar across all drying methods.
Table 1. Analyzed mineral composition (g/kg dry matter) of black soldier fly larvae reared on Mobius farms
feed substrate
Drying methods
Mineral
*
Freeze
-
Dried
Low-Temp-
Dried
High
-
Temp
-
Dried
Microwave
-
Dried
Macrominerals
Calcium
24.00 25.00 21.00 22.00
Phosphorus
7.40 8.20 7.90 8.10
Ca/P Ratio
3.24 3.05 2.66 2.72
Magnesium
2.40 2.70 2.60 2.70
Potassium
10.00 14.00 10.00 14.00
Sodium
0.62 0.73 0.64 0.73
Sulphur
3.40 3.60 3.30 3.50
Microminerals
Copper
0.01 0.01 0.01 0.01
Iron
0.13 0.15 0.13 0.14
Manganese
0.35 0.37 0.37 0.35
Zinc
0.14 0.16 0.14 0.15
*
Results are from 1 sample (n = 1)
;
g, gram; kg, kilogram; Ca, Calcium; P, Phosphorus; Temp, Temperature
Conclusion and implications: The mineral composition of BSFL reared on Mobius farms feed substrate was comparable to that of other
BSF larvae reared on different substrates reported in the literature. The high concentrations of Ca, P, and other essential micro minerals
such as Fe and Zn depict a high potential of the larvae as a suitable feed ingredient for animals that require these minerals, such as poultry
and fish.
Acknowledgements: This project was supported by funding from AgriFutures Australia as part of the Emerging Industries Program.
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Nutrition
References:
AOAC International, (2002). Ash of Animal Feed. Official Methods of Analysis of AOAC International (17th ed.)
Chia, S.Y., Tanga, C.M., Osuga, I.M., Cheseto, X., Ekesi, S., Dicke, M., van Loon, J.J.A. (2020). Nutritional composition of black soldier
fly larvae feeding on agro-industrial byproducts. Entomologia Experimentalis et Applicata, 168(6-7), 472-481.
Park, B.S., Um, K.H., Choi, W.K., & Park, S.O. (2017). Effect of feeding black soldier fly pupa meal in the diet on egg production, egg
quality, blood lipid profiles and faecal bacteria in laying hens. European Poultry Science, 81, pp.1-12
Romano, N., Sinha, A., Powell, A., & Fischer, H. (2023). Journal of Insects as Food and Feed, 9(1), 43-53.
Veldkamp, T., Duinkerken, G.V., Huis, A.V., Lakemond, C.M., Ottevanger, E.A., Bosch, G., & Boekel, T.V. (2012). Insects as a sustainable
feed ingredient in pig and poultry diets: A feasibility study. Wageningen UR Livestock Research, Report 638.
How to cite this paper:
Gadzama, I. U., Malcolm, J., & Malcolm, C. (2024). Mineral composition in black soldier fly larvae: A promising alternative to fishmeal
and soybean meal in livestock feed. In Proceedings of the 35th Biennial Conference of the Australian Association of Animal Sciences and
the 20th Asian-Australasian Association of Animal Production Societies (Vol. 35, pp. 334-335). Melbourne: Australian Association of
Animal Sciences.
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