Reducing feed-food competition in aquaculture and livestock is a way to decrease the environmental impacts of the food system and to free up large areas of arable lands to potentially produce more food
. Previous studies showed that almost 50% of the feedstuff used in aquafeeds are causing feed-food competition
. Indeed, f ed aquaculture utilizes fish resources that could have been eaten directly by humans, but are used to grow more desirable species due to market demands. Furthermore, the quality of soybeans, maize, wheat, and other agricultural crops used in aquafeed , may or may not live up to food-grade qualities, but they are indirectly competing for land that could be used to produce food-grade crops. In general, food-competing feedstuffs have lower environmental footprints than farmed aquatic or terrestrial animals fed these resources
, hence the interest to feed farm animals mainly with by-products that humans cannot or do not want to eat .
Tilapia is an aquaculture species of global importance, with a high contribution to food supply, especially in Asia and Africa. It can be cultured in various production systems (pond, cages, tank, raceway, RAS), with a var ying need for external feed inputs and feed conversion efficiencies . Depending on the systems, and locations, the feed used may contain high-quality ingredients potentially competing with human food and/or non-food competing by-products . The total human-edible yield of tilapia can also be variable, as this fish can be consumed in various ways from the use of the fillet only, to the consumption of the whole fish, depending on fish size , processing technologies, and culture . All these factors may influence the food in / food out ratio of the tilapia farming systems leaving unclear which are net consumers of human edible nutrients, and which are net producers .
This study aims to quantify and compare the net contribution to human food production of contrasted tilapia farming systems from various world regions. To do so, we calculated the human-edible protein conversion ratio (HePCR) i.e., the quantity of human-edible protein in the feed divided by the quantity of human-edible proteins in the animal products, for different tilapia farming systems . These tilapia case studies were taken from peer-reviewed Life Cycle Assessment studies and covers the broad range of rearing systems that can be used in tilapia farming . Overall, t his study discusses how the feed, the farming system and the valorization of fish by-products can influence feed-food competition in tilapia farming systems.
1. Van Zanten HHE, Herrero M, Van Hal O, et al. Defining a land boundary for sustainable livestock consumption. Glob Chang Biol. 2018;24(9):4185-4194. doi:10.1111/GCB.14321
2. Sandström V, Chrysafi A, Lamminen M, et al. Food system by-products upcycled in livestock and aquaculture feeds can increase global food supply. Nat Food. 2022;3(9):729-740. doi:10.1038/s43016-022-00589-6
3. Poore J, Nemecek T. Reducing food’s environmental impacts through producers and consumers. Science (80- ). 2018;360(6392):987-992. doi:10.1126/science.aaq0216