World Aquaculture - June 2024

48 JUNE 2024 • WORLD AQUACULTURE • WWW.WAS.ORG al. 2007). The well-being of farmed fish species is greatly impacted by feed quality, and feed manufacturers need to pay close attention to this because feed quality is largely determined by how effectively essential nutrients are balanced in the feed (Jahan et al. 2021). To ensure the production of highquality, cost-effective feed, the integration of certain micronutrients such as minerals may improve feed efficiency and utilization, lowering feed costs. Mineral requirements for many fishes are still poorly understood, mainly due to the difficulties involved in their study (Lall 2002). Fish require macro- and micro-minerals, as they help in several functions such as transmission of nerve impulses, acid-base balance, normal functioning of muscles, osmoregulation, serving as enzyme cofactors and activators, and in the formation of skeletal muscles (NRC 2011). Fish may obtain some minerals such as calcium, sodium and potassium readily from the surrounding water environment (FAO 2017, NRC 2011), but they typically cannot get adequate amounts of phosphorus, zinc, iron and copper from water (Oliva-Teles 2012, NRC 2011). Thus, these must be supplied by the diet through nutritious feeds (Tang et al. 2012) as indicated in Figure 3. The Need for Mineral Fortification While BSFL meal offers a sustainable and protein-rich alternative, using raw BSFL in aquafeed can be limited by several factors. Continued in-depth analysis of the BSFL nutritional profile reveals some gaps, especially in essential minerals such as phosphorus, and some trace elements such as zinc and selenium, which may lead to mineral deficiencies such as impaired growth and development, weakened immune function and reduced stress tolerance. These essential minerals are vital as they play a pivotal role in health, growth, and overall well-being of aquatic species. One of the key limiting factors associated with BSFL-based diets is achieving a balanced mineral profile. This is because while BSF larvae are good at converting organic waste into high-quality protein, their natural mineral profile varies depending on the substrate they are reared Aquaculture has been a vital part of global food production and has now evolved into an economically and environmentally sustainable industry producing a wide variety of products. Because of expected population growth, the world will require an additional 23 million tonnes of aquaculture production by 2030 to maintain current per capita fish consumption (FAO 2017). Therefore, continuous improvement in this sector is crucial. Most farmed fish are produced using aquafeeds which employ high quality fishmeal (FM) and fish oil as primary ingredients because of their balanced essential amino acids, easy digestibility, and palatability, all of which are crucial attributes to enhance nutrient digestion and absorption (Oliva-Teles et al. 2015). However, increasing demand for fishmeal (FM) and other plant-based proteins such as Soybean in feed production has led to a global concern for the need to search for alternative sustainable protein sources. The gradual decline in wild fish catches and the growing demand for aquaculture feed has resulted in a dramatically reduced supply of FM and increased feed prices (Tippayadara et al. 2021). To overcome these challenges, significant research efforts are being made to reduce the dependence on traditional protein sources and seek sustainable proteins for aquafeed production. Over the last few years, researchers and feed manufacturers have focused their efforts on reducing FM inclusion levels in commercial fish diets while, at the same time, maintaining fish health and the nutritional quality of the final products. Several types of feed including animal and insect proteins, plant proteins, and aquatic plant-based diets have been investigated in an attempt to seek alternative solutions. Among these, insect protein has been acknowledged to be a promising solution in aquaculture feed production (De Souza-Vilela et al. 2019). Black soldier fly larvae (Figure 1) is gaining increasing popularity in the aquaculture industry relating to their exceptional nutritional profile and minimal environmental impact. Substitution of expensive conventional protein diets with low-cost high-quality protein such as black soldier fly larvae meal (BSFL, Figure 2) has been suggested in several studies. However, studies have revealed that it is crucial to pay more attention to addressing dietary mineral requirements in the composition of aquatic animal diets (Gatlin et Solving the Mineral Puzzle to Enhance Black Soldier Fly Nutrition in Aquafeeds Evalyne W. Ndotono, Menaga Meenakshisundaram, Chrysantus M. Tanga, Shaphan Yong Chia and Fathiya M. Khamis FIGURE 1. Analyses of Black Soldier Fly larvae have revealed some occasional nutritional gaps, especially in essential minerals.

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