By : Dr Mustapha ABA. Aquaculture Scientific Expert. Fish Nutrition. Rabat. Morocco.
The growth of aquaculture and the increasing demand for farmed fish have led to an increase in the price of meal and used in fish feed in recent years, which represents a constraint for the development of aquaculture in Africa, considering that aquaculture feed represents 50 to 70% of production costs, this has led to a growing interest in alternative sources. Over the last decade, insect meal has gained popularity in the aquaculture feed industry in Africa, due to the rising costs and decreasing availability of fish meal, insect meal is now seen as a promising ingredient in aquaculture due to its nutritional value, efficient feed conversion and sustainable production potential. The growing interest in insect meal as a substitute for fishmeal in aquaculture has gained momentum in recent years, following the significant number of scientific publications and research studies devoted to the subject, indicating a growing recognition of the potential benefits of insect meal.
Introduction
Due to the rapid growth of the human population and rising living standards, the demand for seafood is increasing ( Alfiko et al., 2022). With the decreasing availability of wild fish and shellfish, the only way to meet the growing demand for animal protein is through aquaculture ( Daniel, 2018 ; Stankus, 2021 ).
Africa’s population is expected to reach around 2.53 billion by 2050 (UN, 2023) and the demand for food and protein will increase dramatically, which the current linear food system may not be able to meet. Consequently, the aquaculture food production sector will play a key role in food and nutritional security on the continent, as aquaculture is the fastest growing food production sector and a major contributor to global fish production (FAO, 2024).
According to the latest statistical report published by the Food and Agriculture Organization of the United Nations (FAO, 2024), global aquatic animal production reached a new world record of 185 million tonnes (live weight equivalent), with a forecast of 204 million tonnes in 2030. Aquatic animal farming produced around 94 million tonnes, or 51% of the total, overtaking capture fisheries for the first time, which produced 91 million tonnes (49%) (FAO, 2024).
Aquaculture feed is a critical factor influencing the production of the aquaculture industry and affecting its output, since it accounts for 50-70% of production costs (Aba, 2020), which represents a constraint on the development of aquaculture in Africa.
Nutrition plays a key role in the aquaculture industry, influencing fish growth and health, as well as the quality of the end product, farm profitability and waste production. The development of balanced, efficient and cost-effective diets that meet the nutritional requirements of species has made aquaculture nutrition one of the most important areas of research and development in the sector (NRC, 2011; Fiorella et al., 2021).
Fishmeal in aquaculture nutrition
Fishmeal, generally obtained from marine fish, is commonly used as the main source of protein in aquaculture feeds due to its high nutritional value and its attractiveness to various aquatic species (Daniel, 2018; Dhar et al., 2024). Rich in nutrients, FM is the best source of high-quality protein with a balanced content of amino acids, omega-3 polyunsaturated fatty acids, minerals, vitamins (biotin, choline, vitamins A, D, E and B12) and trace elements (iodine and selenium) (Hardy, 2010; Macusi et al., 2023; Hussain et al., 2024). Fishmeal represents 50 to 70% of the total material in fish feed (Jannathulla et al., 2019). It is highly regarded as a source of dietary protein because it has an excellent amino acid composition and is easy to digest (Olsen et al., 2019). However, its use means that the farming of farmed fish depends on the capture of organisms from the natural environment, a situation that does not favour sustainable aquaculture and also makes this meal an expensive input due to the current fishing situation, all of which have caused the price of FM to increase by around 300% in recent years (Hussain et al., 2024).
Fishmeal (FM) is obviously insufficient to meet the huge demand for fish feed from growing aquaculture production, so there is an urgent need to find an alternative protein source to replace fishmeal (FAO, 2022; Wang et al., 2023). Among the sustainable solutions suggested for the aquaculture production sector is a shift from conventional to alternative food systems (FAO, 2020).
It is for this reason that aquaculture research aims to reduce the use of FP in feed by finding more sustainable and cost-effective substitutes, but with comparable protein quality. Consequently, the search for alternative and sustainable proteins has become a topic of great importance (Lin et al, 2022; Bansemer et al., 2023).
In Africa, the aquaculture sector has developed in response to the growing demand for fish protein resulting from population growth and changing dietary preferences (FAO, 2022). The continent’s growing intensive aquaculture relies heavily on the availability of high-quality feed, traditionally based on fishmeal (FM). However, the availability of FM is becoming increasingly limited, making it expensive and unaffordable (FAO, 2020) for most aquaculture producers in Africa.
Plant meals
In the search for sustainable solutions, the scientific community has been faced with the challenge of finding alternative proteins to FM that reduce the pressure on fisheries and are more environmentally friendly (Torrecillas et al., 2017; Reis et al., 2019). When considering these alternatives, several factors need to be analysed to ensure their technical and economic feasibility, including protein content and nutritional quality (i.e. EAA profile and digestibility), the presence of anti-nutritional factors (ANFs) and production costs (Gatlin, 2007; Hardy, 2010; Oliva-Teles et al., 2015).
The main problems with these plants are their unbalanced essential amino acid (EAA) profile, in particular methionine and lysine deficiency, low protein content, high NFA and fibre content and non-digestible carbohydrates which affect their use as an alternative feed for fish (Glencross et al., 2014; Cummins et al., 2017; Simmon et al., 2021), in addition, plant-based feeds are less suitable for fish (Daniel, 2018, Alfiko et al., 2022), furthermore, plant proteins are highly vulnerable to mycotoxin contamination that could adversely affect fish growth and health (Maulu et al., 2024). There is therefore an urgent need to explore other sustainable solutions.
Insects meal
Insects are the most abundant species on earth, both on land and in water. Within the arthropod phylum, insects are grouped as the most common type of segmented animal (Giribet and Edgecombe, 2019). The production of insects as a food source is seen as a viable strategy that could transform the current food framework of animal protein production sectors (FAO, 2013; Van Huis, 2019). Currently, an increasing number of feeding trials have been conducted using insect meals to replace part of the FP in aquaculture species, and most of this research has shown promising results of replacing part or all of the FP with insect meals, although this depends on the fish and insect species. (LU et al., 2020 ; Hua, 2021 ; Liland et al., 2021 ).
- Insects Sources of Proteins
Unlike fishmeal and plant proteins, insects can be produced intensively in a short period of time with low arable land requirements, reduced water consumption/use, lower greenhouse gas (GHG) emissions and conversion to biowaste ( Gasco et al., 2020 ; Pulido-Rodriguez et al., 2021).
In recent years, the use of insect meal in aquaculture has grown exponentially, due to its nutritional value, particularly as a source of protein (Belghit et al., 2019; Guerreiro et al., 2020; d’Alfiko et al., 2021); Kierończyk et al.,2022) and Karapanagiotidis et al., 2023). Table 1 summarises the amino acid profiles of fishmeal, soybean meal, black soldier fly meal and milling beetle meal.
Table 1. Essential amino acid profile (% amino acid/100 g protein) in two insects and two meals (FM and SM) used in aquaculture.
BSF : Black Soldier Fly ; TM : Tenebrio molitor ; FM : Fishmeal ; SM : Soybean meal.
The amino acid profile presented by MSN and TM meals shows adequate levels of most of the essential amino acids, compared with fish meal. With regard to the amino acids present in the dry matter of the different insect meals (Table), black soldier fly in particular resembles the composition of fishmeal and may be one of its possible substitutes (Henry et al., 2018; Lu et al., 2020; d’Alfiko et al., 2021 and Kierończyk et al., 2022).
- Insects Sources of Lipids
Research into the effects of including insect products in fish feeds has mainly focused on insect meal as a source of protein rather than insect oil/lipids as a source of lipid (Hossain et al., 2023). The fat content of insects varies considerably, from 10 to 60%, and is generally lower in adults than in larvae or pupae (Xiaoming et al., 2010; Barroso et al., 2023). Insects are also rich in n-6 fatty acids but deficient in n-3 fatty acids (Hawkey et al., 2021), so different strategies are used to improve the fatty acid profile of insects. The n-3 fatty acid content can be increased by using an appropriate substrate, thereby improving the nutritional value of insects (Hameed et al., 2022).
Insects in animal feed in Africa
Entomophagy (the consumption of insects by humans) is a practice that has accompanied humans throughout their history and continues to be relevant in various regions of the world, mainly in Asia, South and Central America, as well as in Africa. In most countries on the continent, insects are mainly consumed as supplementary food (Paiko et al. 2012; van Huis et al. 2013; Niassy et al. 2016; Babarinde et al., 2021). Of all insect species, more than 2,000 edible species have been recorded worldwide, of which 470 species are found in Africa (Van Huis, 2013; Kelemu et al., 2015). Several studies have reported that the incorporation of insects into animal diets has been widely reported to have nutritional, economic, environmental and health benefits (Abro et al., 2020; Tanga et al., 2021; Chia et al., 2021; Kolobe et al., 2024).
Industrialisation of edible insect production, commercial processing and product development remains limited in some parts of the world, including Africa (Tanga and Kababu, 2023). Several food manufacturers in Africa have shown significant motivation and willingness to pay for and integrate insect-derived proteins into animal feed (Chia et al., 2020) and it is established that around 2,300 active insect farms exist on the continent (Figure 4), of which less than 2% are considered to be large-scale insect farms, over 80% of farmed insect species in Africa are produced for animal feed, while 15% are for human consumption. In contrast, only 5% of farmed insects are used for both food and feed (Tanga and Kababu, 2023). The black soldier fly (BSF) (Hermetia illucens L.) is the fastest growing insect farming industry, as shown in the figure. Current estimates show that the volume of dried black soldier fly (DSF) larvae production in Africa is 19,732 tonnes per year (Tanga and Kababu, 2023).
Fig. Distribution of semi-domesticated and domesticated edible insect species in Africa. Countries shaded in white have no insect farming activities and those shaded in brown have operational insect farms for food and feed.
The use of insects as animal feed has been reported in several African countries, including South Africa, Nigeria, Togo, the Democratic Republic of Congo, Angola, Benin and Burkina Faso (Mutungi et al., 2019).
Termites are the insects most commonly used in animal feed in Africa. Several genera, mainly Macrotermes, Odontotermes and Trinervitermes, are traditionally collected or trapped by small-scale farmers in sub-Saharan Africa to provide a source of protein for chickens, guinea fowl or turkeys. This practice has been particularly well studied in West Africa. In Ghana, a recent survey (Boafo et al., 2019) showed that 42% of traditional poultry farmers frequently feed termites and only 11% never feed termites to their poultry. In a national survey in Burkina Faso (Sankara et al., 2018), 78% of poultry farmers reported providing termites to their poultry, but the rate varied widely by region and province. This practice is also observed in other African regions (Munyuli Bin Mushambanyi and Balezi, 2002; Rutaisire, 2007).
Insects and aquaculture in Africa
Insect meal is a promising alternative to the protein sources currently used in aquaculture feeds because of its high protein (35-61%) and lipid (13-33%) content, as well as other health benefits such as high energy, fat and fibre content, minerals, vitamins, chitin and other macronutrients (Van Huis et al., 2013; Ojha, et al., 2021; Siddik et al., 2024). It is worth mentioning that, in many cases, insects are part of the main diet of freshwater fish (Ferrer Llagostera et al., 2019), and that many marine fish also feed on crustaceans, which are also arthropods, thus sharing some of their characteristics with insects (van Huis and De Prins, 2013).
Interest in the use of insects as a sustainable and healthy protein source for humans and farm animals has increased in recent years, and insect meal has recently been proposed as another potential alternative (see table 2) to cover protein needs in fish diets in Africa (Kenis et al., 2014; Sspuuya et al., 2017; Tanga and Kababu, 2023, ; Gbai et al., 2024).
Table 2: Comparison of the 3 protein sources in aquaculture
Consumers and aquaculture products fed with insect meal
Interest in insects as an alternative feedstock for farmed fish has grown as a result of the environmental impact of their production, which is lower than that of conventional feedstuffs due to their short supply chain (Madau et al., 2020), their feed conversion rate and their nutrient content, particularly protein (Barroso et al, 2014; Lock et al., 2018), and are environmentally friendly for aquaculture (Hoffmann et al., 2021), however, the acceptance of insect proteins in aquaculture is not only linked to technical and economic limitations (Smetana et al., 2016), but also to consumer preferences and attitudes (Domingues et al., 2020).
Insects can represent a valuable and cost-effective source of animal feed in Africa. However, many factors, including food neophobia and the social and cultural context, can affect consumer perceptions of food products derived from insect technologies.
Consumer perception of the use of insects in aquaculture feeds is conducted in developed countries, particularly in the European Union (EU) (Maulu et al., 2022, Roccatello e al., 2024). In addition, different cultures and beliefs are likely to affect perception, although further studies are needed to confirm this. The results of the study conducted in Mali, DRC and Niger (Nguezet et al., 2024) and in Mali, Niger and Ghana (Traore et al., 2024) show that consumers in all these countries agree on the use of insects (Black Soldier Fly: BSF) as animal feed and on the consumption of eggs, fish and meat from animals fed with BSF.
Therefore, further studies are needed in different countries, at least the main producers, and among consumers in different cultures to determine the future of the use of insects in aquaculture feeds. Wider adoption of the use of insects in aquaculture feeds is likely to depend, to a greater extent, on aquaculture producers and consumer acceptance (Maulu et al., 2022).
Conclusion
The introduction of insect meal as a raw material in nutritional formulations for animal feed and aquaculture in Africa is a reality and opens up new prospects for the production sector, encouraging debate on the sustainability of aquaculture combined with the quality of alternative food products as possible substitutes for high conventional raw materials with greater economic value and environmental impact. Among the insects of interest, the black soldier fly has characteristics that make it viable for application in aquaculture due to its short life cycle, ease of management and ability to transform organic waste into quality protein and lipid biomass, which can positively promote the sustainability of the aquaculture production sector in Africa, where the use of insect meal is still low and far from being used as the main protein ingredient in the formulation of nutritional compounds for the commercial cultivation of aquatic organisms. The African insect production sector needs more research and investment at industrial level, but it is emerging as a promising alternative sector for aquaculture nutrition.
