Animal nutrition has undergone a significant transformation in light of the growing awareness regarding the environmental impact of the food industry. With the rapid increase in demand for fish for human consumption and aquaculture providing a significant portion of such supply, there arose a need for sustainable alternatives in feed production.
The traditional use of fishmeal, obtained from small wild marine fish, as a fundamental component in animal feeds such as for pigs, poultry, and farmed fish, has created unsustainable pressure on marine fish resources. The continual depletion of wild fish stocks has rendered fishmeal increasingly scarce and expensive, prompting the industry to seek alternative sources.
Over the years, aquaculture has significantly grown as a source of fish for human consumption. Starting from 1974, this practice provided only 7% of fish destined for human consumption, whereas by 2014, this share increased to 44% (FAO 2016b).
A substantial portion of the total fish production in 2014, approximately 10%, was used to produce fishmeal and fish oil. Fishmeal, derived from small wild marine fish containing a high percentage of bones and oil, is commonly deemed unsuitable for direct human consumption but represents a high-quality component in the feed for pigs, poultry, and aquaculture.
However, the growing scarcity and escalating costs of fishmeal result from the excessive exploitation of wild fish reserves, with over 30% of fish stocks in 2013 (FAO 2016b). This situation has prompted the poultry sector to decrease fishmeal usage from 60% to 12% between 1988 and 2010, while the aquaculture sector increased its usage from 10% to 56% during the same period (Olsen and Hasan 2012; Msangi et al. 2013).
The quest for sustainable alternatives has led to the exploration of alternative protein sources without the drawbacks of plant sources, such as the presence of anti-nutritional factors and lower protein content. Particularly, some insect species, like the black soldier fly (Hermetia illucens), seem to offer interesting prospects. Tests conducted with Atlantic salmon have shown that the complete replacement of fishmeal with insects had no adverse effects on the fish's growth, organoleptic characteristics, and flesh consistency (Lock et al. 2015).
Similarly, meal derived from the black soldier fly represents a suitable protein source for various farmed fish species such as the African catfish Clarias gariepinus and the blue tilapia Oreochromis aureus (Adeniyi and Folorunsho 2015; Anvo et al. 2016; Bondari and Sheppard 1987).
This transition to using insects as an alternative protein source is not without challenges. The decrease in long-chain omega-3 fatty acid concentration in insect-based feeds might require their supplementation in fish diets to ensure a complete nutritional profile.
Nevertheless, the inclusion of insects in fish diets signifies a significant step toward more sustainable and resource-respectful feed production. This could alleviate the pressure on the depletion of wild fish resources while maintaining a thriving and sustainable fish industry.
The increasing use of insects as an alternative to fishmeal could revolutionize aquaculture, offering a more sustainable solution adaptable to future animal feeding needs.
In conclusion, the introduction of insects into fish diets represents a promising innovation in animal nutrition, pointing towards a more sustainable and environmentally respectful sector.